So good evening everybody, and thank you very much for joining us for tonight's webinar. I'm really excited to introduce one of my friends and co-workers, Sophie McMurra. So, Sophie qualified as a registered veterinary nurse in 2011, and after working her butt off, she passed the Academy of Internal Medicine for Veterinary Technician exam in Washington, DC in 2016, and she became a veterinary technician specialist in small animal internal medicine.

Sophie is one of 3 head nurses at North West Veterinary Specialists in Frodium in England. And Sophie's areas of interest are endocrinology and emergency medicine. And this evening, Sophie is going to be discussing the how, what and why of lab for RVNs.

So over to you, Sophie. Thank you very much, Caroline, and thank you everybody for joining us this evening. OK, so tonight I'm gonna talk about laboratory analysis, and this is an essential part of our role as an RVN or whether you are a veterinary care assistant, a laboratory technician, there should be something in here for all of you.

And I'm going to discuss many different aspects of the laboratory tech role, whether it be from sample collection, sample handling, the storage, or the packaging of these samples, because all of those things are as essential as each other to ensure that we can get a prompt and accurate diagnosis for our patients. And it's also good that we have a good level of knowledge on the laboratory values that we're running every day. If our vet is busy in a consultation and we have a critical patient in front of us, I don't want to, we shouldn't be ideally just printing off those results and waiting for that vet, which should be interpreting those results and having a look to see actually what's going on with our patients.

And that will just allow us to be able to implement a quicker and more effective care level of care to our patients, particularly those who are sick. Now, there's a couple of different areas that we're going to talk about. So we've got sample collection.

Common in-house tests, renal and hepatic. We'll talk briefly on urinalysis and then a small section on blood smears as well. OK, so we're all RVNs.

I'm not gonna sit here and talk to you about how to take blood samples, but there are just a couple of hints and tips and a few take home messages that we can utilise and tailor for our individual patient needs. So a jugular sample is the preferred method. It is straight from a central vessel and it is great for our larger volumes.

I know that many people do still refer immediately to the leg or the peripheral vessel, but if you can, the jugular vessel is the preferred method, and it is quite easy once you get used to it. Now there are some contraindications, so I have coagulopathies written down here, that's if any patient seems to have a blood, a blood clotting disorder, or maybe you don't have a diagnosis of a clotting disorder, but the patient's in with something like epistaxis, a nosebleed. Maybe you've noticed some areas of or pinpoint bleeding maybe on the gums, the square of the eye or down the midline of the abdomen.

And if you do suspect a coagulopathy or a clotting disease, then we need to tread carefully when we're looking at the jugular vessel, and those cases we would go for a peripheral vessel in the leg. And also if we have any signs of head trauma, then we don't want to be raising that patient's head and occluding the vessel, which will increase that pressure above the vessel and increase that intracranial pressure. So for these patients, the peripheral vessels are great.

They're good on a daily basis for small volumes, and you can take samples from an IV catheter if you have to. It's not ideal, and I'll tell you why in a moment, but if you have a patient who's maybe doesn't like to be handled or is a little bit tricky, then you can always take blood from the IV catheter if you need to. Now, if you are going to do this, just don't do it too quickly.

So the amount of times I've seen people applying such negative pressure to that syringe that the blood is almost bubbling when it's coming into the syringe. So that's gonna destroy a lot of our blood cells, so we don't want to see that. And we just need to be careful that we are being cautious with this sample and we don't aspirate too quickly or we're not too rough with him.

And ideally it should only be when you plate the IV catheter. If it's already placed, we shouldn't be going back to that IV to try and get further samples. And then finally, I don't know how many of you place or nurse patients with central catheters into the jugular vessel, but if you do have any critical patients and you work in a maybe a hospital or a practise which has overnight care, then a central catheter can be ideal for the more intense patients and those that may need multiple blood samples taken, such as a diabetic patient, a DKA patient.

And if you need large volumes or frequent volumes, you can do it all without disturbing the patient. So it's, it's a great resource to use. Now this is just a little take home message, a reminder that we should always fill the blood to the offline because if we don't, particularly if we're doing a haematology, then it can cause the cells to shrink.

If we're sending that off to the lab to look under the microscope and analyse those cells, we don't want any alterations that could alter our patient's results falsely. And you can get abnormal haematological results as well if you're doing a haematology and it hasn't been filled through the line, you may, it may well throw out some abnormal results on the machine. And finally, just always remember to fill the EDTA tube last.

And the reason for that is because the anticoagulant within the EDTA tube is made up of potassium salt. So even if you don't touch the inside of the, the tube, but you hover close to it, I've seen the results be affected just by hovering close to the inside of these tubes, and the potassium will be falsely elevated, and it also collates the calcium, so the calcium will be low. So that's a hallmark sign of.

Someone has actually touched EDTA rather than our patient needs treatment for a hyperkalemia, a high potassium value. So always question that if you're not expecting a high potassium value, yes, you've seen one on the results. Always check with the person, have they filled the EDTA tube last before we act on that result.

OK, so we'll talk briefly about urine. So we have free catch is the most natural method. You can do many different tests from this, whether it be your specific gravity, your dipstick.

It should be collected in a sterile kidney dish, and we should always be going for a midstream sample. One thing to stress is this type of sample is unsuitable for culture. We should not be culturing a free catch sample.

There's bacteria on the precute or the vulva. It may be passing through fur on the way out, and even if it is a midstream sample in a sterile kidney dish, there's no way of guaranteeing that the sample is sterile. So ideally, if you do culture.

If you do culture one of these samples, you won't know whether that bacteria is from the pot you've collected it in, whether it's from the prep use or whether it's from the bladder itself. So it's just, it's inaccurate. We could also place a urinary catheter as another option.

It may be traumatic, although they do seem, they do seem to tolerate this quite well. It's contraindicated if we're suspecting a urinary tract infection, so we wouldn't want to place one in those guys. And it is it's the method of collection for a prosthetic wash sample.

Now, the gold standard method of collecting urine is a cystocentesis. It's still conscious, it's easily done by your vet, and this is perfect for all samples, including your culture because there's minimal risk of contamination. It may just be contraindicated in coagulopathic patients, so if you do have any patients with severe bleeding disorders, we want to avoid popping a needle into the bladder.

OK, so we'll talk briefly on some common in-house tests. So, when I was thinking about what tests to talk about. It made no sense to discuss pre-op blood work.

So, pretty much every practise will have their set pre-anesthetic blood panel that they do for the majority of their patients. But do we know why we're doing it? So there's a few different things that tend to make up the majority of practises pre-anesthetic blood panel, and that's a PCV in full protein, blood glucose, blood urea nitrogen and also creatinine.

So they are just the minimum things that we should be doing. And if you have patients who have cost issues and we tend to run a full biochemistry and they can't afford it, you can just pick out some of these things which will give you a lot more information on what you're dealing with. Now, if we run a packetel volume, that tells us we'll delve into all of these a little bit further on.

But if we look at a PCV for example, that tells us if it's low, there may be an anaemia present. If it's high, there may be a hydration problem. So in combination with your total protein, if you have a high PCV and a high total protein, that may tell us that we're looking at a dehydrated patient.

So maybe this patient needs fluids before we go putting it under anaesthetic. It's already dehydrated and then we anaesthetize it with our fluids. We need to be careful and be looking at those renal values.

We don't want to take these patients into renal problems. Blood glucose. So this is useful for hypo or hyperglycemia, particularly useful for your very young.

So hypoglycemia is can be common in puppies or very small patients. And a hyperglycemia, if you're maybe anaesthetizing an older patient, maybe for a dental or another procedure, we want to, if we see a hyperglycemia, we need to question could it be diabetic, and do we need to stabilise this patient before we go along with the procedure. And then we have BUN and creatinine.

So this tells us quite a lot about our renal disease. It can tell us about a few other things which we're going to talk about a little bit later on, but they are really useful if we have it and we know that it's normal, we know that we have a little bit more of a safety barrier before we go and anaesthetize our patients. OK, so The normal PCB for a dog, 34 to 55.

But the normal PCD for a cat is 27 to 45, so that's significantly lower than that of the dog. And I work in a referral hospital and occasionally we have had cats referred to us for anaemia, and when we've run the PCV it's 27 or 28. And that's because people tend to remember the canine values, we don't always remember the feline values.

That is totally normal for a cat. That was to be a dog, it wouldn't be, but it's important that we do remember the differences and the felines are naturally lower. And the total protein for both species is exactly the same, so 55 to 77.

So, when we run our PCV in total protein, it is vital that we do both together. We get a much more rounded picture if we do both together and do either of them individually. They're both quick and cheap and easy to run, so we might as well make the most of that easy sample.

So a low PCB and low total proteins could indicate blood loss. So if we have haemorrhage, that blood is just being lost, it's the fluid and it's also the red blood cells, so both of those lines will go down. We have a low PCV with a normal protein level that could indicate anaemia.

So either our body isn't producing the red blood cells, the protein's absolutely fine, nothing wrong with the proteins. Or maybe our body's destroying our red blood cells, something like immune-mediated hemolytic anaemia with the immune system starts to target and attack those red blood cells. So the blood cells are going down, and the proteins are totally normal.

So that tells us it's likely to be an anaemia. And then a high PCV and a high total protein, dehydration. Rehydrate these patients, run it again and it should have gone down.

Now, I need a quick message to point out is cats tend to cope a lot better with anaemia, and they often present present with much lower PCBs than the dogs do. And quite often they can come in with a PTV. The lowest I've seen is 6 in a cat, and they're still sat up, they're conscious, a little bit tackyne, but if a dog were to present with anything less than 10, it would be severely dyne and pretty collapsed.

The cats do tend to cope a little bit better, and that may just be because. For a cat to get from 27 to 7, that's a much smaller drop than to get a dog from 34 or 35 down to 7, so they'll have lost a lot more of those red blood cells, so it's just a bigger jump for the dog. And it's quite common that we see anemias in cats secondary to other diseases.

We know that they definitely can get it secondary to renal disease because of the lack of erythropoeating that's produced by the kidneys, which stimulates the bone marrow to produce those red blood cells. We have renal damage, or kidneys may not produce the erythropoeating, and then we start to see the effect in the anaemia. But also secondary to many other conditions.

Cats have very sensitive bone marrow, so if they do have other conditions, it can quite easily become overwhelmed and you might start to see a quite a low anaemia with these patients. And if you do see any abnormal blood results, so maybe we do have a low PCV then we should always be making a blood smear. Ideally, have a look at it in-house.

You won't get used to blood smears unless you start looking at the normal ones and then you can start to look at the abnormal and always send one externally. OK, so when we're looking at blood glucose, we will have all done this so many times, so I'm not going to teach you how to do it, but there's just a few things to point out. And one of the important parts is that these these blood glucose monitors are calibrated for capillary samples.

So ideally, we need to be taking the sample from a capillary, and you can see here on the right, there's a picture of the sweet spots just on the the pinna of the cat's ear. And if you don't always take it from a capillary, and the most important thing that we do is that we're consistent with our collection. So don't take a sample from the jugular vessel, then take it from the capillary, then take it from the peripheral vessel, because I've seen changes of up to 5 millimoles per litre just from changing the site.

So if you're gonna start taking it from a jugular sample, stay with the jugular sample, and each time, just repeat it from that same, from the same sample site. It doesn't have to be the same vein, you can go the other side, but it should always be from a central vein or a peripheral. If that's what you've started with.

And if you do change site, then it's important to just note that on the patient's record because if there is a big jump, then we know actually it could well be, because we've changed the site and now we're we're going to start taking it from the capillary. Now, if you use the lancets, that these Alpha Track 2 are ideal for diabetic patients. They can be bought on Amazon for about 90 pounds and they're the only ones that are actually calibrated for veterinary use.

So they're much more accurate. The lancets that come with these are really good. They're less traumatic to the patients, and they get a really good blob of blood.

And if you, if you can shave the ear at just a tiny amount, that would help a little bit, but you don't have to. If you just smear a little bit of Vaseline over the area before you do it, put some warm cotton wool underneath and then use the lancet on top. Then it's just the Vaseline just.

Causes a little bubble of blood rather than it absorbing into across the skin of the ear and into the fur, it just kind of brings up that blood so you'll get a little blob on top and then you can utilise your your alpha tract there as well. And it is ideal for the majority of diabetic patients, but just be cautious with if any patients are really nervous and really head shy, then you don't have to go on the ear, you can go on the gum, and you can also go on the paw pad as well, which seems to be tolerated quite easily and quite well. OK.

So albumin. So albumin is quite a useful thing to know about, but it's something that we often don't necessarily look for in our patients. So albumin is one of our, it's our biggest protein within the vascular system.

And it makes up 35 to 50% of our total plasma proteins. So if we have a decrease in our proteins, maybe in our total protein that we ran alongside our PCV, the chances are the albumin is probably affected because it makes up such a big proportion of our proteins. Now, if we have albumin loss or hypoprotemia, just meaning low protein, then there's a couple of areas where this could be coming from.

Now it's important to remember that the albumin is synthesised in the hepathocytes, which is the liver cells. And liver dysfunction can certainly be one of those conditions that can cause a decrease in the albumin level. We can also see it with renal disease, so we know that our kidneys shouldn't be losing protein.

We shouldn't be allowing that protein to escape. We should be keeping it within the vascular system and retaining it within the body. But if we have renal disease, we may well start to see some proteins slip through that net, and we may start to lose them.

So that's certainly another thing for the list. Burns, which luckily we don't see commonly in veterinary practise, but if you do, then the sebum that leaks out on the skin that contains a high level of protein. So quite often you will see a low protein level with burns.

And also increased gastrointestinal losses. So maybe we have a patient with IBD and we're starting to lose our proteins into that gastrointestinal lumen, and it's just being taken out with our faeces. So some of these GI conditions can cause quite a severe hypoalbuminemia.

And you might start to see patients with puffy legs or edematous face, and that's the typical hallmark sign of a patient who has a low albumin. And then finally, it's important to Points out that albumin being one of our large proteins, is the protein which maintains that colloidal osmotic pressure within the vascular system. So what that means is, It maintains that colloidal pull, so when your proteins are within your vascular system, which is where they should be, it draws all of the fluid into the vascular system.

So when they start to go low, then you may also start to see the fluids, leaking out as well because that automatic pull has decreased. And that could happen with an increased vascular permeability, so maybe we have FIP. Maybe we have systemic inflammatory response syndrome or SAS.

So this just all causes a vasculitis or an increase in our vascular permeability. So we almost get leaky vessels and then the proteins leak out, and it can take the fluid with him. So they're quite useful to know about, if you do have a patient who comes in with peripheral edoema or edoema around the face, check the albumin and see what's going on.

And also, if you're aware that it causes the colloidal osmotic pressure, check the blood pressure as well, because if we do, if we are leaking out our proteins into the, the peripheral spaces, then our, our, our blood pressure may also drop as well. So it's a good, it's a good practise to check the patient's blood pressure in these, in these conditions. OK, so we have lactate.

So lactate is relatively new. It's been around for maybe 1012 years. But do we know, do we use it actively in practise, and if we do, do we know what we're looking at?

So it can be quite complicated to explain why it's produced. So hypoxia, it can be produced from hypoxia. So when we have hypoxia, it could be either from a true hypoxia, so maybe the patient is, it does have some respiratory issues, or maybe it could be from a hypo perfusion.

So maybe our oxygen level is perfectly fine, but we're not perfusing those cells and we're not. We're not allowing that oxygen to reach those cells. That could be things like dehydration, or maybe the patient has a cardiac issue, so the, the oxygen level's fine, but the pump is not.

Achieving what it should so the heart is not pumping effectively and it's therefore not perfusing that oxygen around to those tissues. So when our body has a level of hypoxia. We start to go through a cascade of events.

So our body requires oxygen on a daily basis, so we're classed as anaerobic. So we have, we're classed as aerobic. So we have aerobic metabolism on a daily basis, but when that oxygen is depleted, we need to do something about it, because our cells could start to die if they don't have oxygen.

And the thing that we start to do is we start to convert some of those tissues in some of these areas to an anaerobic state just to allow it to survive that little bit longer, for if this oxygen doesn't return. And it just goes through a cascade of events, so one of those events is the production of lactic acid or lactate. If you do see a hypoxia occur, then you will quite often see an increase in your lactate.

So it could be from hypoxia or perfusion, they're the two most common things. And an elevated lactate is classed as anything above 2.5 milli per litre.

Now, as you can imagine, this is quite a strenuous task to convert your body and to do all of these things. So it requires a lot of energy and it has quite a high metabolic rate. So we start to use up our glucose.

So as your lactate increases. Blood glucose and just check it alongside because you may well start to see that the blood glucose is going down with the more severe cases, and that's just because we have that metabolic demand and we need that energy to convert our body to try and cope in this whatever state the patient is in and to try and convert our body into an anaerobic state, if that makes sense. I hope it does.

And because lactic acid is an acid, we may also start to see an acidosis form. So if we run an epoch or a an electrolyte panel that usually has your blood gases on there, then we may start to see a drop in our pH along with an increase in the lactate. So we used to say, if your lactate is above 10, it means pretty much game over for the patient, but it doesn't mean that anymore.

So what we tend to say is yes, the higher the number, the more severe the problem. But the important thing is, is it coming down with treatment. So if you put this patient on fluids or you start to treat whatever it is that's causing this, and the lactate then when you repeat the sample, maybe half an hour or 1 hour later, is not budging, that's when we start to ring alarm bells.

So if it is coming down and maybe we've increased our patient's perfusion. So our, our oxygen is being nicely perfused to those tissues now, and that lactate should start to decrease. And if it does, that's great and it's a great way to monitor the response to your treatment.

Is your fluid therapy high you know. It's not just that the patient is not responding, it may be something that actually we need to treat it more aggressively. So it's a great tool to have and particularly in our really sick patients.

It could also be, we quite commonly see this in the GDB. So if we have a an organ like the stomach which is twisted and cut off the blood supply, that's a hypoxia to the stomach, so you will quite often see a really high lactate above 10 with a GDV patient. OK, so I work in internal medicine and one of the most common electrolyte abnormalities that we see is potassium.

So we see many patients with vomiting and diarrhoea, and when you vomit or you have diarrhoea, you lose your electrolytes in that vomit and diarrhoea. So quite often they'll come in with a low potassium value. So one of the questions that I always used to ask is, if a vomiting and diarrhoea patient has been admitted, yeah, we run the sample and it's normal.

So normal is 3.5 to 5.5 and say the patient's potassium value is 3.5, why do we still put them on potassium?

So the reason for that is because potassium is renally excreted. As soon as we put our patients on fluids, it may be just about maintaining the normal level for now. As soon as we put our patient on fluids, we're gonna cause, we're gonna promote diaretes in the kidneys, and our patient's gonna start urinating more.

Just because it's on fluids. So therefore, our potassium value is suddenly about to drop. So that's why we tend to still put them on a maintenance potassium value, and that's just 20 milli per litre, even if our value is 3.5, if our patient has losses like vomiting and diarrhoea.

Now, a serum potassium value below 2 milli per litre can cause muscle weakness, and this can include the respiratory muscles and anorexia. And hypokalemia should be supplemented ideally by spiking the bag of fluids according to its potassium level. Now, if we do spike these fluids, then we should not ever flush these lines or bolus them.

So if we have a dehydrated patient, even if we're worried about potassium value, we should hydrate them first with fluid bolus. Then once we're happy that their dehydration or their shock is under control, then we can. Start introducing with the maintenance rates, we can start putting potassium spike fluids on them.

So if we boost potassium too quickly, it can cause cardiac arrhythmias, bradycardia and also cardiac arrest. So it's important that we, we have little stickers which we put next to the IV catheter line. I think we have a picture on the next slide, and they just go down the line and it can go next to the port, and it just says do not flush.

And that's just a really important message to just make somebody stop and second guess what they're about to put down that line and why they shouldn't be flushing in, is whether it's flush, whether they're given some paracetamol, whether they're given an antibiotic, it should not go down that line. So ideally have a T connector with a second port on the IV catheter and you can use that second port for any fluid bolus or drug bolus. Now if you do spike the patient's bag, then we should ideally be checking our potassium value again, reassessing it at least ideally every 24 hours.

And if the supplementation is above 60 milli per litre, which is relatively high, then we should be rechecking that twice a day. And when you do bowl us these bags, when you put the drug in, just make sure that you're you're mixing that bag thoroughly. So we invert it 4 times as a set protocol before we will link it up.

So the last thing we want is a little bubble of potassium sat next to that port as we're about to start the fluids running through. OK, so yeah, you can see here that's the, the label I was talking about doing our flush, just next to the port, which is really useful. And you can just buy these labels quite easily from some of the veterinary suppliers, and you can write on it what you like, you can get all different drugs and many different things, so this do not flush is a really great, great tip.

So we may also see the opposite of a hypokalemia, so we may see a high potassium volume. So potassium is one of the main electrolytes managed by fluid therapy, and therefore, if we have a hypokalemia or a high value, then fluid therapy is usually our first protocol to bring that down. Now it depends on the level of the the hyperkalemia as to whether we just put them on fluids or whether we treat.

With drugs as well. So. There could be many different things that can cause a hypokalemia.

Your blocked cat is one of the common ones that we see because that urinary obstruction is not allowing the body to excrete that potassium, so it's building up. And usually even though it is quite high, once we empty that bladder and get rid of that obstruction, it's likely to start coming down. However, depending on how high it is, we may still need to give therapy for it.

And hyperkalemia can be acute in onset. We can see normal kalemic patients, or we can also see hypokalemic patients who tend to be chronic renal diseases if we're talking about kidney disease. And if the potassium value is above 7 or 7.5, then we tend to give insulin.

And we need to give this a long glucose as a long type glucose. Because we know that when we give glucose, when we give insulin, our glucose is lowered. That's why we give them to our diabetic patients.

Glucose is also a co-transporter of potassium, so it sends both of those electrolytes into the cells. So if we give this to decrease our potassium value, it will also decrease our glucose. So we need to make sure we're monitoring and supplementing the glucose alongside.

And we can also see cardiac arrhythmias or bradycardia. So if you have a cat in with a bradycardia, say maybe 100, which is quite low for a cat. 100 beats per minute heart rate, then we need to start to think, right, this potassium is affecting the heart, and we we can see bradycardia, arrhythmias, and tall spiked T waves on your ECG is the hallmark sign, and usually they're about 2 to 3 times the size of the QRS complex.

So if it's just mildly increased, it's unlikely to be relevant. But it should be at least 2 or 3 times the size of that QRS. It's really tall and that's likely to be from your hyperkalemia, quite commonly seen in your blocked cats.

Now, if it is causing cardiac issues, we can give calcium gluconate. Now calcium gluconate can be given IV, has to be given slow over 2 minutes, and the dose is 0.5 to 1 mg to 1 mL per kilo.

And this just blocked the cardiogenic effects of the hyperkalemia, but it does not decrease the serum potassium value. We will protect the heart, but you'll still have a hyperkalemia and that's why you need your insulin alongside and your fluid therapy. OK, so samples which require a media processing.

These are the samples that you take and you run. You have to run straight down the corridor to the lab and get them run as soon as possible. So arterial blood gas, I don't know if many of you take many arterial samples, but if you ever do, or if you're working with somebody who does.

Then that needs to be run straight away. The longer that sample is out in the environment, the longer the environmental oxygen will alter the 02 results, and then it defeats the point of doing an arterial sample. You could have just got a vascular sample.

If you want an accurate result, you need to run to the lab. Also, potassium and lactate, these gradually increase in samples if they're left over 2 hours in the lab. And ionised calcium, ammonia, glucose and insulin assays, these are all things that need to be run pretty quickly.

Now ammonia, this is something that we might test for in our, maybe we have a liver patient, liver disease, or maybe we have a portosystemic shunt with neurological signs. So if we test our ammonia, as that warms up to room temperature, that value will start to decrease. So with these, we tend to keep a few different blood tubes in the freezer.

And then as you take them out, it's already cold, it's ideal for these samples, and then you can just sit them on a block of ice while you're running, while you're getting the sample. And running it to the lab and it just prevents any warmth getting into that that sample, warming it up and potentially giving our patients a false, accurate, a false result which is within the normal limit. And then that would delay treatment and it will be detrimental for our patients.

So all of these little things that we do, can really help how our patient receives the care. And also glucose, if you're Taking a sample for glucose, those red blood cells are alive within that within that blood tube. So we know that we metabolise glucose as an energy source, and that's what glucose is in our vascular system for.

If that's sat in the lab for hours on end, those live blood blood cells are metabolised in that glucose. And if you're running something like a glucose with an insulin assay, maybe you're checking for an insulinoma, then we need to make sure that this is as accurate as possible. So just spin it down as soon as you can and get that dealt with straight away.

OK, so we'll we'll talk a little bit about renal and hepatic values. So, we'll talk a little bit about azotemia, and the definition of this is just abnormal levels of nitrogenous waste products in the bloodstream, i.e.

Your urea and your creatinine. So if you have elevations in urea and creatinine, that means your patient is asymic. So when we're thinking about aoemia, we need to think of the origin.

Is it pre-renal, meaning before the kidney? Is it renal in origin? So is it actually coming from the kidney itself?

Or is it post renal? And we'll talk about what those three mean. So a pre-renal aemia is likely to be from hypoperfusion.

So maybe the kidneys aren't being perfused like they should. So that could be things like dehydration. Shock, congestive heart failure, or maybe haemorrhage.

So if we have dehydration, our renal values are likely to increase, they're not not usually really, really high, but they can increase enough to flag it on our our renal values on our blood test. And if this is maybe a young patient, you know, it's not a patient that we're suspecting kidney disease, there are other things that we can do to just check is this pre-renal. Maybe something quick, easy, cheap, run your in specific gravity.

If they're dehydrated, it should be concentrated. If it's not, and it's . It's dilute, then maybe with dehydration, maybe we do have some renal issues there and that does correlate with some renal disease.

So there's a few different things that we can use to check this, and we can also run our PCD and protein. Are they both elevated? Is this looking like a dehydration?

Or next, is it renal in origin? So is it within the kidney itself? So maybe we have an acute kidney injury.

Maybe we have chronic kidney disease or any other renal disease itself. And then finally we can have post renal, so this just means anything that's after the kidney. So this can commonly be things like urinary tract obstruction, maybe a blocked cat, you blocked dog, or urinary tract leakage, maybe we have a ruptured bladder.

Maybe the patient's been involved in a road traffic accident. And this is where we tend to see in a lot of those post-renal cases, we tend to see a high potassium value alongside those, alongside the increase in our renal values, and that can be one of the signs that we can test alongside just to see what else is going on. OK, so BUN or blood urine and nitrogen, what does it mean?

So this is an end waste product. And when we have the metabolism of amino acids, breaks down ammonia. Ammonia is a toxin.

It's a waste product that we do not want in our body. The ammonia is taken to the liver where it's converted into urea. So urea flows then to the kidneys, and then that's where half of the urea is excreted.

So our renal function is assessed based on the kidney's ability to remove this waste products from the circulation. So if we have renal damage or something else going on that's affecting the kidneys. We may start to see an increase in that urea because they're not able to excrete it properly.

And if the renal function is impaired, or maybe if it is something like dehydration, maybe that waste product just isn't being taken to the kidneys in order for it to be excreted. And that's why you might start to see it mildly elevated with dehydration. OK, so creatinine is found in skeletal muscles and it's formed as part of muscle metabolism.

So, once our muscles are being metabolised, then this just enters the different bodily fluids via diffusion. And that's just as the, as we have muscle metabolism going on maybe from exercise from those muscle cells. And therefore, the total volume of creatinine within the bloodstream reflects the amount of muscle mass that we have.

So you can see here in the background, I have a picture of a greyhound. So they have a really high muscle mass, and they have a high metabolic muscle rate as well. So they have a naturally elevated creatinine level because it has to reflect the amount of muscle that they have in their body because that's where creatinine comes from.

It comes from the muscles. But then if you think of it the other way, so if we have a, a really underweight cat, maybe we have a kidney disease, chronic kidney disease patient. If they have a really low muscle mass, then the creatinine will also reflect that.

So in these patients, we need to interpret these results carefully because we could have a an underweight emaciated cat with really low muscle mass, who has chronic kidney disease, but the muscle mass is that low that it actually appears that the creatinine is normal on the blood volume. Now if we have an underweight cat who has barely any muscle, it shouldn't have a normal creatinine and it should be low. And if it isn't, then we need to start thinking actually this cat might have kidney disease.

And in those cases we tend to see it back after treatment and once it's gained a lot of the muscle mass, maybe it's on a renal diet and it's a much better bodily condition, then repeat those blood tests and see where that creatinine is sat, because it will then reflect a healthy body weight and a healthy muscle mass, and that's when you may then start to see. An increase in that creatinine value and a true chronic kidney disease starting to show. OK, so liver cells or liver enzymes?

So when we look at liver cells or liver enzymes, we look at the liver can work in compartments. So the whole organ doesn't have to be damaged, it can be functioning perfectly fine, but we may just have some areas or compartments which are damaged. And the liver cells can regenerate from damage, which is a really important message to remember.

And we have a few different liver enzymes. So one of them, which we'll go into a little bit more depth on the next slide is ALT. And this is an enzyme that's released with hepatocellular damage, so liver cell damage.

Maybe we have a tumour, some form of neoplasia. Maybe we've had a toxin that damages the kidney, or maybe the patient, sorry, the the liver, or maybe the patient has been hit by a car and we've had a blunt force trauma. So if we have destruction or damage to those liver cells, your ALT will increase.

But the blood level of the ALT does not correlate with the severity of the disease. So say this patient was a trauma patient, it may have a really sky high ALT because it's been hit by a car and it's caused loads of liver damage. That doesn't mean that actually in a few days' time or in a week, that liver that ALT could be back to normal.

So even though it's sky high, it doesn't mean that it's non-repairable and it doesn't mean that it's really severe disease. It just means that it's had damage and it's repaired itself. Don't let that put you off, when you see that, it doesn't mean that it can't be fixed.

And ALP this tends to be elevated with things like cholestatis. So cholestasis just means anything that causes the blockage or the slowing down of the flow of bile through the liver. So pancreatitis can slow that down because of the inflammation around the liver and the pancreas, and also a cholelith, so a gallstone, if there's a gallstone there, then it will block the the bile duct and you might start to see an increase in your ALP along with other enzymes as well, like your bilirubin.

And ALP is also an isoenzyme in dogs due to excess glucocorticoids. So if you have a patient who is cochingoid, who naturally secretes an increased level of glucocorticoid, or maybe you have a skin patient who's on prednisolone, they're on steroids long term. Then the machine will read the steroids as ALP because it's made up of the same isoenzyme.

So if you have a patient on steroids, always interpret the ALP cautiously because it's likely to be caused by the steroids rather than the liver itself. Now, neither of these tests tell us anything about liver function, so it could be functioning perfectly fine. These are just different enzymes that tell you about maybe point to different areas.

And in cats, even mild liver enzyme elevations are important, and that's because, this says it on the next slide, that's it's in a moment. So liver enzymes for cats have a really short half life, so it's about 3.5 hours, whereas the half life of liver enzymes in a dog can be about 70 hours.

So what that means is If a cat has an increase in the liver enzymes, they will, if the problem's not going on, it wouldn't have had it, it won't still have it on the bloods, it will have gone because the liver disease is gone and the body's metabolised it. So if those liver enzymes are increased, it means there is a problem going on right now, whereas a dog, it could have been 4 days ago. So we do need to act a little bit quicker when we're looking at liver enzymes in cats.

And that's just one thing to just bear in mind, but if you do see it on a cats . Biochemistry results versus a dog. And then we'll talk a little bit about bilirubin.

So this is a molecule that's derived from the breakdown of your blood cells, mainly the haemoglobin that's contained within the blood cells. It's metabolised in the liver, and then it becomes part of the bile. So we know that once bilirubin or bile is in the gallbladder.

When the patient eats, the gallbladder contracts and it sends that bile out and into the duvein and via the common bile duct. So that just coats the food, it then starts to metabolise and break down the food, and it's excreted in the faeces. So We may start to see high levels of bilirubin in our bloodstream, which can cause jaundice, and this can be caused from conditions such as a block bile duct.

But if we have a black bile duct, it's not able to escape and therefore it builds up and we become jaundiced. Maybe we have hepatocellular dysfunction so our liver cells aren't working properly and aren't able to metabolise that bilirubin. So we start to see a buildup.

Or it could be an excess in our red blood cell destruction. So we've just said that that bilirubin is increased as a result of red blood cells breaking down in the spleen and releasing that haemoglobin into the bloodstream. So this happens on a daily basis, but it's a nice normal level that we can.

Keep on top of and that we can maintain. But if we have an excess in our red blood cell destruction, we're releasing a lot of haemoglobin into the bloodstream and then we will start to see jaundice. And it's important to remember that jaundice stains the blood.

So even if we do have a patient, say, it does have IMHA and we start to treat the patient, even though the patient is being treated perfectly well and it's responding well, this jaundice is likely to stay for a couple of weeks or months because it stains the blood cells, it stains the tissues. So it's important to make the owners aware not to use. Jaundice as a response to therapy to don't think it's not being, it's not being treated well because there's still jaundice, because it's just stained, then it will go.

OK, so ALT we have touched on this briefly, but this is a marker of hepatocellular damage. And there are a few causes that could cause an increase in ALT. That could be endocrine disease or diabetes, it could be inflammation like pancreatitis, it could be a trauma, or it could be things like your, maybe different drugs, so, xylitol toxicity or blue-green algae.

Then we'll talk briefly on your analysis, there's not much to this bit. So urine specific gravity is something that we do in-house every day. So the one thing I want to point out about specific gravity is that it should always be assessed alongside hydration status.

So we know that if we have a dehydrated patient, our specific gravity should be high because it should be concentrated. I've really concentrated urine when we're dehydrated. So if we run a USG and it's within the normal limits and it's not concentrated.

Then that's why it's so important to look at the hydration status, because actually, yes, it may be within the values, but that's not normal, that's abnormal. So that tells us that our kidneys aren't concentrating like it should be because that should be a high value in correlation with the hydration status. And always remember to get the specific gravity sample ideally before we put our patients on fluid therapy, because this will automatically promote diuresis and it will start to dilute our urine because of the fluid therapy, so it won't be as accurate.

And there are inappropriate concentrations that come along with different conditions. So if we have a patient on prednisolone, steroid therapy with PUPD, we may see alterations in those, those results. It may be low.

Cushing's disease causes really severe PUPD, so we may well see a low value with that and the same with pyometritis or hyperthyroidism. Now, when we're looking at sending off urine to the lab, when you spin down the Eppendorf tube, so when you've taken off your sediment, you've looked at it under the microscope, you will have a really concentrated small sample left in the bottom of that tube. Use your culture swab and just mop up the rest of what's in that Eppendorf tube.

It's the most concentrated, it's full of bacteria, if there is any, and that's gonna give you the most accurate culture result. And also if you have a pH monitor like this red one that we have on the side here, try and utilise it as much as you can in practise, because if we're looking at urine in particular, this tells us a lot about what could be causing the condition. So certain.

Udinary crystals, for example, will only be present with an acidic urine, whereas others may only be present with an alkaline urine. So it actually gives us a fair bit of information and it allows us to rule out certain diseases as well. So it's a really useful thing that we can use in-house.

And then if we are sending off any urine, maybe we've made up a few slides and we're gonna send them to the lab or maybe we're looking at blood smears. Just one message to say about when we're packaging them and we're sending them off is they should not be stored anywhere near formalin. So even if you've just put a few drops into a sample just to fix it into your urine or into any other sample, we shouldn't be storing that next to any slides or any smears because it can start to affect the cells.

And when you send them to the lab, they may not be as accurate. So even if you put one in cotton wool and the other in cotton wool, but yet it's still in the same pack, that will still go through the layers of cotton wool. So they should ideally be one's in one box and one's in another box in another area.

So bear that in mind if you do have some important smears there and then you sat it, you've sat it next to formalin. OK, so just a short few slides on blood smears. So blood smears are really important in-house and also for sending off.

So these are something that we do in our huskies, and it's variable as to whether people continue to do them in practise. If you see, if there's any haematology samples going off to the lab, you should never send them without a fresh blood smear, ideally straight from the syringe without even being in the blood tube. But even if it's been in your EDTA still perfect, do a blood smear.

And that just allows the lab to get the most accurate fresh results before. Sending it off before it's been stored in a blood tube where it can change. And also if you see any abnormalities with the likes of your PCV or any other cell counts in-house, do a blood smear and have a little look.

The more you look, the better you'll get. And practise makes perfect. So we might look at a blood smear for white blood cells, we might look at a platelet count, or we might be looking at our red blood cells.

So with anaemic patients, their blood is a little bit more watery. So if you have a wider angle between the slides, then you tend to get a nice smear because it's quite watery, it will often run off the edge of the smear and you won't get your feathered edge. So just increase your angle and you'll get a nice feathered edge there.

And then the opposite with your hemo concentrated patients. So if a patient's really dehydrated or has a really high PCV their blood's likely to be a little bit thicker. So just narrow that angle and then you'll get a longer smear when you're doing your when you're running the slide across.

These are vital for any forms of anaemia, especially IMHA because you need to examine a blood smear under the microscope in order to diagnose IMHA and practise makes perfect, even if you go through loads of different slides, you've emptied the box completely, at least you're practising, and then the next time you look at it under the microscope, you will be that step better. Because no one will improve if they don't keep repeating what they're doing and keep on trying. Now this might seem really, really simple, so apologies if it is, but just a few things that, I wanted to put in here here because they rarely bug me when I see somebody do it in practise.

So just to explain the areas of the blood smear, so you have your thick area at the bottom and if you can see my mouse, no, I don't think you can. So thick area down here, so we don't tend to look at that area. It's this area that we tend to, we'll look at and also the feathered edge.

So you should have a good area on your slides which is just one cell layer thick. And this is where we'll do a lot of counts if we're looking at red blood cells, and then you should have a nice curved feathered edge here. And this is where some of the white blood cells or your platelets might go to, so it's important that we have this one cell layer thick, and then the feathered edge at the end, because otherwise we can't really interpret what we're looking at.

And always write in pencil. So the amount of time to see people writing in Sharpie. And, or even in pen.

So when you send these off to the lab, they receive hundreds of samples, hundreds of slides every day. They have to just submerge the entire slide into the the stain. And it goes away and it, it will stain in the slide.

So one, you will then pull the slide out and the sharpie has spread across into the stain, probably ruined it, but you'll also then have a blank slide. So that's quite dangerous. You may not get results back for that patient.

But also it will leak out and it is likely to just damage the stain rather than giving you any producive results, and it may also go on to stain your cells as well. So always write in pencil, it doesn't come off in the stain, and just keep one in lab, which you can use for all of your smears. And if you see anybody doing it, tell them off.

And then down at the bottom, I've written the name and then always label the slides with what it actually is. So the amount of times you might see somebody doing a liver FNA which is just, Blood. So they'll do a load of smears, send it to the lab, and it just looks like a load of blood smears.

They don't know it's actually from the liver. So always label the slides with what it actually is, where has that blood come from? So they can look very similar, so it's important to identify so that the lab know exactly what they're looking at.

And then I've just put in a quick reference guide. So these are just some of the normal laboratory values for our patients. So PCV total protein.

The one that's on there that I haven't discussed is PH. So your blood pH should be anything between 7.35 and 7.45.

If it's any less than that, it's acidic, if it's any more than that, it's alkaline. And it is useful to look at that alongside some other results. We don't have time, unfortunately, to talk about it in this slide.

Blood gas analysis is a whole different lecture of its own, but it is quite useful if you can start getting used to the normal values and start looking at your blood results, because, yes, as RVNs we're not allowed to diagnose. But we can certainly understand what's going on with our patients. And if we look at those samples as they're coming out, those results, then we can act on them quickly and really make a difference to our patient care within the hospital, especially if those patients are sick.

So start looking at them, start interpreting them, and even if you take a picture of one of The, results if you're not sure of it, and your vet's busy, and then ask them about it at the end of clinic when it's a quieter time, they might have time to go through the results. You don't have to tell them what you thought, just ask them what, what the diagnosis was or what they thought of those bloods and test yourself until your confidence starts to build that actually, you do know what's going on. And then you can start having open discussions about these things because we're not just lab technicians to just run the samples.

We play an important part in the whole picture for our patients, and it's our job to try and improve our interpretation skills so that we can, be there for our patients when they need us. OK, so that's it from me. If you do like internal medicine, I do have a Facebook and Instagram page.

It's called Veterinary Nurse Medicine Geek. So please follow me if you do have social media. And otherwise, I hope you've enjoyed the talk.

OK, thank you very very much Sophie, for that really, really informative talk on lab. I've really, really enjoyed that, and yeah, lots of lots of little snippets to try and get, get your, gets your brain thinking all over again. So if anyone has any questions, .

An answer box or the Q and A box at the bottom of the screen. So if you want to type in there and then send them on over to Sophie, we can ask her, we can put a few questions to her. So we'll just give you a couple of little minutes just to see if anyone does have any questions.

The thunder's just the thunder's just started just in the nick of time just for me doesn't go too early. See, it was, it was holding off for you, just waiting, waiting till we got to this slide. Well there's nothing come through as yet, Sophie, so I think you, you may be off the hook there a little bit and you can go and yeah, go and get yourself all all settled down with a cup of tea this evening.

So thank, thank you again for a really, really interesting talk. And yeah, I've, I really, really enjoyed that. And I hope everyone else did, and I hope it's something that everyone can take back to practise and, yeah, get stuck into your lab samples and ask questions, ask your vets questions.

I, well, I know what I, myself, I still pester for question, answers on lab samples, and, it's really important to actually to do that as well. So I just want to thank Lukey in the background at the webinar vet for sorting everything all out for us, and thank Sophie again for a wonderful talk and thank everyone else for attending this evening. So I hope everyone has a lovely rest of the evening.

Good night.