Hi everyone, my name's Sophie McMurra. I'm a registered veterinary nurse and a veterinary technician specialist or VTS in small animal internal medicine. I work at a referral hospital called North West Veterinary Specialists, where I make up one of 4 head nurses and I'm the head nurse of the internal medicine department.

And today I'm gonna talk to you about your analysis for RVNs. So laboratory analysis is a really important part of our role as an RVN and all of the different aspects are as important as each other, whether that comes from the sample collection, the sample handling, or the storage or running of the sample. And all of these things, if done correctly, will help us gain an accurate and quick diagnosis for our patients.

And also having a good knowledge of the laboratory values can help improve patient care. If we come across something in the lab that we know is really important and needs acting on quickly, we can go and alert the vein surgeon to these results. So before we delve into your analysis specifically, I'm gonna give you a brief.

Recap on the ordinary system so that we know what we're looking for, what we're looking to achieve by performing your analysis and what things your analysis can tell us. And also we're going to discuss the other the other tests that we can perform to give us more overall reviews such as blood tests as well to go along with the your analysis. So, on a daily basis, the body's cells generate many different chemical byproducts, some of which may be useful and they can be recycled and reused in the body, but others can be harmful, and these need to be excreted.

Now the urinary system is the main route for filtering waste products from the bloodstream, and then it's therefore excreted. Via the ordinary tract. So the urinary system is made up of 2 kidneys, 2 ureters, which lead to the urinary bladder and then the outside well through the urethra.

The kidneys have many different roles within the body. They retain and eliminate water and electrolytes, including hydrogen ions, which help us maintain our blood pH. They conserve nutrients such as glucose and proteins, and they excrete a lot of our nitrogenous waste products.

It also plays a very important role in maintaining blood pressure, and it does this via the production of wrenin. We look at red blood cell production because of the hormone that's that's secreted called erythropoietin. It activates vitamin D, and around 99% of all water entering the kidneys is reabsorbed back into the body.

And 30% of all blood volume is sent to the kidneys, so they are really, really important. And the kidneys, once they're damaged, they have very little regenerative capacity, unlike some other organs. Now when we look at the renal system, we have, I'm not sure if you can see my mouse, but if you can, we have this indent here in the the centre of the kidney which is called the hylus.

And this is where the blood vessels, the nerves, and the ureter enters and leaves the kidney. And then just further on from that, this pale pink area in the centre of the kidney itself is called the renal pelvis, and this is where the ureter begins. And then we have the nephrons, which is the functional, they're the functional units of the kidney.

And there are several 100,000 several million nephrons in each kidney depending on the size of the patient, the species, or the breed. And urine production is under the influence of two different hormones, and that's anti-diuretic hormone and aldosterone. So when we look at the nephrons, so the functional area of the of the kidney, it contains the renal corpuscule.

The proximal convoluted tubule, the loop of Henley, the distal convoluted tubule, and then the collecting tubule. And then within each renal corpuscule, we have the glomerulus, which is a bundle of capillaries. Wrapped around the bowman's capsule.

Now, when we look at the formation of urine, there are a few different things that happen within that nephron before urine is produced. So blood, mainly plasma is filtered through the glomerulus and into the proximal convoluted tubule. Large proteins and cells should not enter the tubules unless there is glomerullar damage.

So we look at the glomerulus as being almost like a sieve. So only only the small particles will fit through the sieve. And the larger particles will remain within the glomerulus and go back into the bloodstream, so it won't be filtered through and we shouldn't see any of those larger proteins within the bloodstream.

And if there is some damage to the glomerulus, then we may start to see things leaking out which shouldn't necessarily be there. So if we do see protein in our urine, it can be an indication of glomerular damage, and we'll talk about that in more depth later on. And the fluid passes through the nephron for modification.

So this is where the fine tuning happens. So we excrete and retain different electrolytes depending on what we want to keep and and get rid of. And water and glucose is also reabsorbed heat back into the circulation.

And every different thing that the kidneys excrete and retain, we have something called a renal threshold. And this is the kidney's maximum absorptive capacity. Of each nephron for specific substances, so it only has a certain level which it will reabsorb and anything over that level will be excreted in the urine.

And then the fluid is taken to the collecting tubules where it drains into the renal pelvis and then opens up into the ureters. So when we look at collecting urine sample, there are a few different methods. So the most natural methods that we have is a free catch urine sample.

And this is good for things like urine specific gravity, dipstick, UPCR. It should be collected, ideally in a sterile kidney dish. But because of the way this is collected, so as it comes out of the patient, it passes the prep use or the vulva.

It may pass through some fur, and it can also contain mucus and bacteria. So this method re catch is unsuitable for culture. And when you are collecting the sample, remember to allow some urine to flow out first before obtaining your sample so that it can be a midstream sample.

And this just prevents any large pieces of mucus or bacteria from the the penis or the vulva being in your, your sample. But even if it is a midstream sample, it's still suitable for culture. And then we have urinary catheterization, again good for dipstick and urine specific gravity.

But again, this is also unsuitable for culture. And that's even though it is placed in an aseptic manner, there is an increased risk of external contamination. This method may be traumatic to the patient, it's easy in the dog, but the bitch or cat, it can be traumatic and difficult to place.

And we can use this technique if we need to do a prosthetic wash. And then finally we have cystocentesis. So this is the gold standard methods for collection, and this is suitable for all urine tests, including culture.

It can be performed in a conscious patient. Usually they tolerate it really well. And the only downside may be if you have a particularly nervous or aggressive patient, it may be difficult to collect that sample.

And if you do have any patients with coagulopathy, so clotting or bleeding disorders, it may well be contraindicated, so you need to assess those cases individually, depending on their blood results. OK, and we'll look at urine specific gravity, and this measures the concentration of a patient's urine, and it tells us about the quality of that renal function. So if we have good renal function, the the kidneys should be able to concentrate the urine.

Now, every day it's important that we calibrate the refractometer so that it goes back down to 0, and we just do this with distilled water. Now when we're looking at your in specific gravity, it should always be assessed with the patient's hydration status. So if the patient has a normal hydration status, you can expect the urine to be within the normal range.

Whereas if the patient is dehydrated, they should have a concentrated urine. So the the value of the USG should be increased. So we know that if we have a dehydrated patient, With a USG within the reference range, that may well indicate a reduction in our kidneys concentrating ability.

So we could have some renal disease there. So it's important that we don't just look at the reference ranges and say, yes, it's within the reference range or not. We need to look at the hydration status and what should that urine be doing in relation to the patient's hydration status.

And there are some conditions that may affect the concentration of the urine, such as particularly cases that cause PUPD or diseases that cause PUPD. And some of these can be Cushing's disease or hyperadrenal corticism, pyelonephritis, pyometra, hyperthyroidism, which increases your glomerafiltration rate, hypercalcemia, or if a patient's on prednisolone therapy, which causes an increase in your urine output and causes PUPD. Now if you are going to obtain a urine sample and you're looking at USG, remember to get these before you put the patient on fluid therapy, ideally, because this will just give you the most accurate result before it's.

Diluted with the fluids. Now we've talked about looking at hydration status and There are a few different ways that we can assess a patient's hydration status. So the first of all, we need to look at the patient.

How does the patient seem? Does it have a decreased demeanour? Often with dehydration, we can see an increase in our heart rate, maybe tacky mucus membranes.

Weak pulses, a skin tint. There are many different things that we can look at to try and grade the patients and give them a hydration, grade. But we can also look at certain blood tests.

And one of the most common ones that we perform in-house is a PCB or packed cell volume and total protein. And it's important to always assess these two alongside each other because both of them together give you much more of an idea of what's going on with the patient. For example, if you have a low PCV and a low total protein, that may indicate blood loss because both of those elements can be lost at the same time with haemorrhage.

If you have a low PCV and normal proteins, it may indicate anaemia. For example, if you have a patient with IMHA immune mediated hemolytic anaemia, and you have your red blood cells are being broken down. That's the reason for the low PCV the plate, the proteins are absolutely normal, so that's why I can indicate anaemia.

A high PCV with a high total protein may indicate dehydration. And this doesn't mean that you have an increase in your red blood cells, it just means that the fluids, which they're sat in, is reduced because it's dehydrated. So often the concentration will just be that bit higher.

And that's why it's so important to look at your total protein alongside your PCV each time. And the normal values for a PCV in a dog are about 34 to 55, depending on which textbook you're looking, and a cat is much lower, so around 27 to 45. And then your total protein is 55 to 77 in both species.

And when you're looking at anemias, often cats will cope a lot better with a lower PCV. And they will be able to maintain. Normal bodily function quite well, even with a lower PCV so often I've seen cats with PCVs as low as 6%, whereas dogs tend to look like they're on death's door, anything below about 12.

And cats can often, well, any patients can get anaemia secondary to other diseases. And that can be from bone marrow suppression or if it's Chronic kidney disease that we're looking at, we can have a reduction in our erythropoietin production. And we know that erythropoietin is produced by the kidneys when it detects a low oxygen level, and our red blood cells contain oxygen.

So if there is a reduction in red blood cells, the kidneys will produce erythropoietin, which will stimulate the bone marrow to produce more red blood cells. So if the kidneys are damaged, we may see a reduction in this and we may see an anaemia of chronic kidney disease. And then other ways of assessing dehydration are things such as lactate.

So lactate is produced as a result of anaerobic metabolism. So if you have dehydration, your body may not be able to perfuse all of your cells and all of your tissues as effectively as it would like to. So for that reason, we may start to see hypo perfusion, and the oxygen may not be able to reach those tissues and therefore lactate is produced.

So it can increase mildly with dehydration, and this is one of the handy things that we can use to assess hydration status in a patient. So an increase in your lactate, anything above 2.5 millimoles per litre, can indicate hypo perfusion, hypoxia, or acidosis.

And if we Look at your analysis and we start to think maybe this patient does have kidney disease. There are certain blood tests that we can look at alongside to give us a better picture of what's going on. And one of the first ones that we would look at is creatinine.

Now, creatinine is found in skeletal muscles, and it's formed from creatine as part of muscle metabolism. And then this enters the body's fluids via diffusion from the muscle cells. So the volume of creatinine within the body reflects the patient's muscle mass.

So you can see here we have a greyhound which has a really increased muscle mass. It's using a lot of those muscles on a day to day basis, so it may be normal to see a slightly increased creatinine in a greyhound. Whereas if you think of your old crispy cats that come in, which may have chronic kidney disease or other diseases.

Their muscle mass has been lost and they're quite underweight. The bodily condition score has gone down. So if you see a patient who is quite underweight with a low muscle mass and their creatinine is within the normal.

Reference range or well towards the high end of the reference range or if it's even increased, then that should ring alarm bells that the creatinine is actually much more increased or it would be much more increased if this patient had a normal bodily condition score and muscle mass. So if you do see that often as the patient is treated for the condition that's causing the the muscle mass, the muscle wastage. The creatinine will start to creep up.

So it's very important if you notice that in any of your patients that you start to monitor it and You may well see that your creatinine is increased as the patient starts to get better. And then the next one we'd look at is bludgerya nitrogen or BUN, and this is a waste product caused by amino acid metabolism, which produces ammonia. Ammonia is a waste product which goes to the liver.

It's converted into urea, and then that goes through the glomerulus and enters the renal tubules for excretion. Around half the urea is excreted in the urine, whereas the other half is reabsorbed into the body. And this is a great way to assess renal function.

By assessing the kidney's ability to remove this waste product from the circulation. And if the kidney function is impaired, a sufficient volume will fail to be eliminated from the blood and it will start to back up and it will start to increase on your blood results. When we see an increase in our urea, we call this uremia, and if we see an increase in creatinine, we call this azotemia.

And it just means that they are increased within the bloodstream. And when we see this, we need to look at where it's coming from. And there's 3 different areas that we would look at.

So is it pre-renal, meaning it's coming from something before the kidneys? Is it coming from the kidneys itself, so it's renal, or is it something after the kidneys, such as the urinary tract? Now preenal, so anything before the kidneys, may be caused by hypo perfusion.

So this dehydration fits into this category, but it can also be caused by things like haemorrhage, shock, hypovolemic shock, or congestive heart failure. Whereas if it's from the kidneys themselves, it could be a kidney disease such as acute kidney injury, chronic kidney disease, or any other renal disease. And then post renal, a urinary tract obstruction, so maybe you have a blocked cat or a dog or a urinary tract leakage, so maybe the patient's been involved in a road traffic accident and they've ruptured their bladder.

So it's important when we see An increase in these These parameters on your blood results, we don't instantly just jump to renal disease because there are some extra renal. Areas where it can be coming from. So always think of these three areas and try to pinpoint where about the aotemia is coming from.

So one of the other urine tests that we can do in-house, which is performed quite commonly, is the urine dipstick. Now I'm not gonna tell you how to do this because you will have done a million of them, but I will just tell you little bits about the individual panels. So the first one is a leukocyte panel, and this is inaccurate in both dogs and cats.

So ideally we should be looking at a sediment under the microscope looking for white blood cells on there instead because this gives you an accurate idea of what type of white blood cells, what are we looking at, how many, rather than just looking at a leukocyte panel, which doesn't tend to be accurate. You're in specific gravity again, the same, we should be looking at this under a refractometer. Then we have the protein panel.

So this is useful for looking at proteinuria. So do we have protein in our urine? And we may see protein in the urine from renal loss, or there could be protein from inflammation from the ordinary tract or your blocked cat or hematuria.

And if you do see protein on the dipstick, then it should be assessed relative to your urine specific gravity. So if you have, if you are positive for protein, And you have a decreased urine specific gravity, so urine is very dilute, then that may, those together may indicate renal issues. And then we have urine protein creatinine ratio this isn't on the dipstick, but this is just a more accurate method of assessing proteinuria.

But we can't run this if we have hematuria, because we know the blood contains proteins, so it will be a falsely elevated UPCR or a protein panel on your dipstick. So if you do think the patient has protein in the urine, we would go for a UPCR and we'll talk about this in more depth. More about that in a moment.

If we have blood on our dipstick, this can indicate renal blood loss, maybe inflammation, maybe the patient has a urinary tract infection. Bilirrubin can be normal in dogs from 1 to 2+ can be normal in a canine, whereas it's abnormal in cats. So it's commonly seen with hemolysis, and that's because with hemolysis, that's the breakdown of red blood cells.

Bilirubin is within our blood cells, so we will see an increase in the bilirubin. And it can also indicate liver disease as well. If we see ketones, that can indicate diuretic ketoacidosis.

Glucose may be increased due to diabetes, diabetes mellitus. And remember the cats can get glucosuria from stress hyperglycemia. So if a cat is really stressed, they can have a stress hyperglycemia.

We typically see it around 12, but it can be increased, and some cats can even go up to anything around 18, although we don't commonly see a stress hyperglycemia of 18, tends to be a little bit lower. And then we talked earlier about the kidney's renal threshold of different components and the renal threshold of glucose in cats is 18 millimo per litre. Whereas dogs is 10 millimoles per litre, and dogs don't get stress hyperglycemia.

So anything over 10 will start to be excreted in the urine. So we know that if we see glucose in a dog's urine, it may certainly indicate diabetes. So we need to do some more tests.

A cat, we will sometimes see it because of their stress hyperglycemia, but again, we should follow up with some diabetes, some tests to rule out diabetes, particularly if they have the clinical signs to go alongside. PH can be reasonably accurate, but it's not as accurate as the pH probe that you can have. So if you do have a pH probe, definitely go off that result rather than the dipstick.

So the tick certainly has its place in the lab, but it certainly also has its limitations as well. So just be aware of those things when you're using a dipstick and That will just help you know which results to act on and which ones to ignore. Now if you do see protein in your urine, the more specific test that we can run is urine protein creatinine ratio.

And this should be used for all chronic kidney disease patients. It's semi-quantitative, so it's more specific. And it will give you a figure rather than just a plus plus to say there's some protein there, it will give you an actual figure to work off.

So it's also good for monitoring. But before we perform a UPCR, we need to firstly rule out inflammation of the ordinary tract. Haemorrhage or any protein abnormalities in the blood, because if you have a really high protein count, then you might be more likely to see it pass over into the urine.

Whereas if you have haemorrhage or inflammation in the urinary tract, there will be some blood in there, which contains proteins, so it may give you a false result. For an inaccurate result. Protein urea simply just means protein in the urine and albumin is our largest protein present within the bloodstream.

So this can be present in very small quantities within the urine. And our glomerulus has a selective permeability. So as we mentioned earlier, it's like a sieve.

So only certain things should fit through those holes, and proteins and cells should not be one of those. Anything that does go through the permeable membrane, certain things can then be reabsorbed. And some of those smaller proteins are almost completely reabsorbed by the tubular epithelial cells.

So if we still see protein in our urine, it can indicate an increased glomerular loss. So if there's damage to the glomerulus itself, it's causing there's something wrong with the sieve, and it's causing the loss of some proteins. Or maybe we have a decreased reabsorption.

So if we have issues with any of our the cells involved with the reabsorption, we can then see proteins in our urine. Now, when we look at UPCR, we need to look at it. Is it persistent?

So we don't just take one sample. We need to look at ideally 2 or 3 samples to see if we can say yes, this is a persistent proteinuria and it can then go on to be a sign of chronic kidney disease. It can be used for monitoring for progression of chronic kidney disease because it gives you a value.

So if it's increasing, you know, that the the disease itself may be progressing as well. And the protein urea level does correspond with the severity of the disease. And there have also been studies to show that.

That the treatment of proteinuria can slow down the progression of chronic kidney disease and even increase the survival time. So now that we know that it's really important to Perform a UPCR to see whether there is any protein in the urine because if there is, we can treat it and potentially improve the patient's survival time. So any alterations in the glomerral permeability.

Can be due to glomerular hypertension, so maybe if there's an increase in the blood pressure in the in the glomerulus itself that can force through some of the proteins that wouldn't normally go through. So diseases that cause hypertension can have an impact on the glomerulus and the the level of hypertension within the kidney itself. Endothelial cell dysfunction, so any of those cells that are responsible for any reabsorption, if they're damaged, you may see protein in your urine because they're failing to reabsorb.

Primary glomerular disease and glomerulonephritis has been shown to be the most common disease of the glomerulus. Now there are some other causes that we may see. Primary kidney disease being one of them, so things like chronic kidney disease or an acute kidney injury.

Remember, there are some breeds which are predisposed to protein losing nephropathy just means that we lose proteins through our kidneys with kidney disease. So bear in mind some of those, take note of what breed the patient is. It can be infectious disease such as Lyme's disease or leptospirosis.

Systemic hypertension can affect the glomerulus and how much of those proteins are excreted. Neoplasia, inflammatory disease, certain endocrine diseases such as Cushing's or diabetes, immune-mediated diseases, but also some drugs as well, and particularly certain drugs that can cause PUPD such as prednisolone. So it could be a functional.

Physiological, issue that we're seeing, and this can be mild. We can see things like pyrexia, stress, seizures or extremes of temperatures can sometimes cause a proteinuria. Or maybe it's pathological.

So we do have disease to the medalist, the tubules or disease within the interstitial cells themselves. And renal proteinuria is most often caused by an increasing glomeral filtration of plasma proteins due to hypertension within the kidneys themselves or the presence of immune complexes with immune mediated diseases such as IMHA. Now there are some pre and post renal or some extra renal factors that can cause Proteinuria.

The most common ones can be your post renal issues such as inflammation or haemorrhage of the lower urinary tract. Maybe the patient has uralists. Neoplasia, feline iopathic cystitis.

And anything that causes inflammation or haemorrhage within that urinary tract can cause proteinuria. So we, we need to bear that in mind and rule those out. And we should always perform it with a sediment to look for things like crystals or blood cells within the the urine.

And a normal UPC is less than 2. If you have a UPC of between 0.2 to 0.5 in dogs and 0.2 to 0.4 in cats, that's considered borderline.

Whereas over 4 in cats and over 5 in dogs is classed as proteinuria. So remember that it's important that we have a persistent level of proteinuria and not just a one-off result. So if we do see a value above the normal range or so above 0.4 in cats and above 0.5 in dogs, then we should be monitoring because it could be an early sign of kidney disease.

And typically, we tend to see a value between 0.5 and 2 can indicate renal tubular disease, whereas anything above 2 can indicate that it's coming from the glomerulus itself. And we can just get.

The owner to collect 2 samples at home, bring them in, and we can send off 2 pooled yawn and samples. Now if we're monitoring Protein creatinine ratio, we need to look at Monitoring every 3 to 6 months in stable patients or every 2 to 4 weeks after changes in therapy. So when we say we will monitor, we should repeat the UPCR.

We should look at albumin levels alongside renal markers, your urea and creatinine. Maybe check the patient's blood pressure because we've just mentioned that blood pressure or hypertension can be one of the most common causes of proteinuria. And also perform a physical examination.

Look out for things like weight loss or muscle deterioration. Now, when you're preparing a urine sample to send off to the lab or to look at in-house. There are a few different things that we can do to improve the accuracy of the results.

So we don't just place some in a boric acid tube and send it off. There are a few different things that we can do. And one of them includes putting some urine in an EDTA tube.

And we can also pop in two drops of formalin. Now EDTA preserves cell morphology. And the formalin prevents any deterioration.

So if we're sending urine sample to the lab, it's really important that we do both of these things to preserve the true urine sample. And then we can do a dry prep for sediment examination that we send off. And for this you just spin down in an Eppendorf tube, remove the supernatant, add one drop to a microscope slide.

Drag the spreader across the slide and then lift it up before you reach the end. So this will just create a small pool of urine. And once, once you've waited for that to dry, you can package it up and send it off.

And that's really good for looking at red blood cells, white blood cells or bacteria. If you want to look at one in-house, we should do a wet prep, which is just the normal . The normal examination with your cover slip and if you do send this off to the lab, make sure you send an unstained sample.

Because they are likely to have a a wide range of different stains that they will use, and often the stain can affect the sample itself. And this is good for looking at crystals, so it's great for us to look at in how. And then if you're doing ayan culture.

Which makes up part of the full urine analysis package. We shouldn't just put it in the the actual y in itself. We can use the remainder of what's in that Eppendorf tube and just mop it up with the end of your charcoal swab because everything will be, you'll get direct contact with the most concentrated cells that are in the base of that Eppendorf tube.

If you have a pH monitor in-house, perform your pH test and then just write that on the the laboratory form when you're sending it to the lab. And it's really important to look at urine pH because it can rule in and out certain conditions, urinary crystals, for example. If the urine is alkaline.

Strevite can be on your list, but your rate may not. So there's certain things that you may be able to rule out from a a pH or rule in. So it is, it does have its part and it is really important.

And then when we look at the ordinary crystals, there's 4 of the most common ones. Calcium oxalate being the one that looks like an envelope. We can see this in both acidic and alkaline urine.

And you can also see this with ethylene ethylene glycol toxicity. And then you have urate crystals, which is like your spiky apple, the second image here. You can typically see this with portosystemic shunts or liver disease because of the buildup of ammonia in the bloodstream, which causes the urinary crystals.

And You can see this in acidic or alkaline urine as well. And there's also something to bear in mind is something crystals can form from allopurinol. So if you have a patient with maybe skin disease or something which means that they take allopurinol treatment, they can mimic urate crystals.

So if you see them on urinalysis, always check what drugs the patient is taking so that we can rule out . The formation of these crystals from any drugs. And then we have uric acid being the 3rd 1, which we typically see in Dalmatians.

If a Dalmatian comes in blocked, it's uric acid that we tend to see. And they're diamond shaped and yellowy brown in colour. And then probably the most common one that we see is struvite, and this can be naturally occurring in urine analysis.

So if you take a urine sample and it sits for too long, it can naturally occur. And they have this typical coffin lid appearance, as you can see on the 4th image there. So when we take a urine sample, it's really important that we.

So when we look at your analysis, there's some really important things to be aware of when we're looking at the sample and how we store the sample. So ideally we should be analysing your in from 30 minutes to an hour from the collection. And this just avoids any artefacts or degradation of any of the cells that might be within the urine.

If it's not possible to do this, then ideally we should store it in a fridge for between 6 to 12 hours. And if we do this, there are some things that we need to be aware of. So while you're in specific gravity is affected by refrigeration.

So if you need to do a USG, do it before it goes in the fridge. If the owner brings a sample in and it's been in their fridge, we're unable to test USG on that sample. If you're gonna store it in the fridge for a long time, make sure it has a tight fitting lid, and this just prevents any evaporation and any contamination.

And as the urine cools, it can increase the turbidity of the urine, and crystals can also form as the urine cools as well with the change in temperature. The refrigeration degrades glucose and also bilirubin. It increases the pH from bacterial breakdown and ammonia.

And it can also break down red blood cells and casts in the urine. We can see bacterial growth in samples which are kept at room temperature. And if we're gonna look at if we're going to analyse a sample which has been in the fridge, we should warm the sample to room temperature first.

Although this may not dissolve any crystals once they've been formed. But it just helps to . It may just help to get rid of some.

And before you do any urine sample, always just gently invert the sample and give it a very gentle mix. And this just redistributes any of the elements that may have formed. And when we're looking at culture and the storage of culture.

The culture sample should be stored at room temperature, and this just allows the specimen to grow. Because if you put a culture sample in the fridge, it can slow down the growth of the culture and therefore affect the results. So what we tend to do.

We use the storage boxes in the bottom of the fridge for any samples. But if we're sending off for your analysis, we'll put a separate bag in, we have two boxes outside of the fridge for external samples. And we'll put the culture in there.

And we'll have one box for things like culture or things that need to be kept at room temperature. Just photocopy the form and then you've got a form in each. And we also have a separate box for anything that may contain formalin, which we'll talk about in a moment.

And if you look at your under the microscope, just remember that struvi crystals can commonly form in urine, which is being stored. So remember not to overinterpret them. And that's why it's really important to analyse the sample before it goes in the fridge or ideally within half an hour to 1 hour of it being collected, because it's that's the time when That's the window when you have the most accurate results and you're not gonna see anything that's formed during the storage process.

Now I mention that we have a separate box for anything that contains formalin, and the reason for that is because if you have any blood smears or cytology, they shouldn't be stored anywhere near any formalin or any samples that contain formalin. And the reason for that is because the presence of formalin can alter the cytological samples, even if they're in separate parts. So we can go through the the packaging itself and can affect the blood smears or the cytology on your slides.

So always keep a formalin in a separate container or a completely separate storage area. OK, so that's all from me. I hope you've enjoyed it, and thank you very much for listening.