After bloodwork, a urine sample test is the most important test for evaluating health. NMK-Studio / Shutterstock.com
A cat urinalysis test describes the collective tests routinely performed by veterinarians on a cat’s urine sample. A urinalysis may be performed along with wellness bloodwork as a part of regular preventive health screening, or may be performed for sick cats to help determine the cause of illness and how to treat it. In this article you’ll learn why a urinalysis is important, how samples are collected and tested, and what they tell us about a cat’s state of health.
Understanding the Importance of a Cat Urinalysis Test
A urinalysis is the third most important test of body function, second only to the blood tests looking at complete blood count (CBC) and a serum chemistry profile. As a waste product the body expels, urine can be checked both as an assessment of the body’s normal function but also screened for things we would not expect to find in a healthy cat.
A urinalysis greatly compliments the findings on blood work tests. Without both, there can be crucial details about internal health that will be missed.
When and Why Your Cat Might Need a Urinalysis
Blood and urine samples are the most common samples collected and tested in both human and veterinary medicine. Here are some reasons why a veterinarian may want to check your cat’s urine and why it will be collected.
Routine Health Screening: Urine samples are part of general health screening. Just like in blood samples, we may find early changes in the urine before a cat shows any obvious signs of changes at home. It’s common for veterinarians to include a urinalysis with annual or biannual lab work screening in healthy cats.
Changes in Water Consumption: If you have observed your cat spending more time around the water bowl, this can be a potential signal of medically significant health changes. But in some cases, changes in water consumption may be behavioral or not be a significant change at all. A urine sample can shed light on whether a concern may be present or not.
Changes in Litter Box Use: If you see your cat spending either more time in the box or shorter but more frequent periods, there may be something going on that a urinalysis can tell us more about. Inappropriate urination in other places around the house may be behavioral in nature but can be seen with several medical conditions that a urinalysis can help detect.
Other Health Changes: Changes in drinking or litter box use may not be apparent in all cases, especially for multi-cat homes, for indoor-outdoor cats or cats that spend most of their time in the basement or other sequestered part of the home. There may be other signs of concern recognized instead, such as appetite changes, lethargy or weight loss.
The Urinalysis Procedure: How Vets Collect and Analyze Samples
Urinary bladder shown on ultrasound scan. Ultrasound is a very important part of assessing the urinary tract and collecting a sterile urine sample safely. Chris Vanderhoof and his cat Bart
There are three ways that urine is collected from patients in veterinary medicine. However in cats, there is only one method – cystocentesis – which is a reliable collection method.
1. Cystocentesis
Cystocentesis involves inserting a needle into the urinary bladder and removing a volume of urine into an attached syringe. This method is the most reliable and most frequently used collection method. This is also the only method in cats that allows for a sterile, uncontaminated urine sample, which is important when checking for a urinary tract infection.
The procedure may seem scary and invasive, but it is actually very similar to how a blood sample is taken. With the proper medical training, it is very safely performed and most cats who tolerate blood collection tolerate cystocentesis as well.
Using the ultrasound scanner to help take the sample can make this method even easier. An ultrasound view of the bladder can also help to look for some causes of urinary issues including bladder stones, the presence of sediment or debris, urinary bladder wall inflammation or thickening or a bladder mass or tumor.
2. Free-Catch
Catching a urine sample in real-time as your cat toilets can be very tricky! This method is used often in dogs, but presents a challenge in cats. To have the most reliable sample, you must collect one in mid-stream to reduce the risk of bacterial contamination. Even then, bacterial contamination is very possible.
Once in vet school, when we were learning about urinalysis and needed to provide urine samples from our pets to use in our clinical pathology lab, I managed to collect a midstream free catch sample from my cat Bart. I removed the box lid, hid around the corner, waited until he entered the box and started to pee, then lifted him up by the tail, stuck the urine cup under him and collected a small sample while he looked up at me confused and then ran off.
While I managed to bring the only cat pee sample to the lab and it was an entertaining story to tell my classmates, this is not how collecting a free catch sample would work in most homes with most cats.
Many cats prefer privacy while using the litter box and any affront to that will have them make a quick departure. An attempt like this may also affect a cat’s future desire to use the litter box. Many cats also squat so low to urinate that collecting urine in a cup or tray is impractical.
Another issue with free-catch sample collection in cats is that they use litter, which absorbs urine. We will sometimes send home a product called Nosorb which are tiny plastic granules that don’t absorb urine which can be placed in a litter box to simulate cat litter. However, as most cats are very picky about the type of litter they prefer, the success rate with using Nosorb at home (or in the clinic setting) is low.
3. Catheterization
Catheterization involves inserting a urinary catheter in a sterile fashion through the urinary tract and into the bladder. In cats, this method is virtually impossible – and extremely stressful – without sedation or anesthesia.
The only time this method may be used is when a male cat with a urinary obstruction is already sedated or anesthetized to relieve the blockage and the catheter used to relieve the blockage is used to collect a sample at that time.
Urinalysis Costs
The costs of a urinalysis can vary depending on where you live and the average veterinary costs of your region. Urinalysis is also often included with blood work panels, allowing the cost of the urinalysis itself to be reduced.
According to Care Credit which reviews average costs as of 2023, the cost of a urinalysis can be $40-70.
Embrace Pet Insurance assesses a full urinalysis to be $100-200.
In my own experience, in the Washington D.C Metro area, a lone urinalysis costs between these estimates or just within the low range of the Embrace estimate.
A urine culture, which may be recommended if a bacterial infection is suspected but can’t be confirmed with a basic urinalysis or if antibiotic resistance is a concern, is more expensive and separate from the basic urinalysis. These typically cost closer to $200-$300 in my own experience, but may be lower in other areas. Embrace assesses these to be within $120 – $250.
Interpreting Urinalysis Results: What They Reveal About Your Cat’s Health
The chemical strip urine dipstick is one part of a routine urinalysis. NMK-Studio / Shutterstock.com
A urinalysis includes four essential parts:
General color/appearance
Urine concentration
Checking a dipstick (which assesses several characteristics of the urine)
Examining cells and other solid material present in the urine through a microscope
1. General Color/Appearance
The color of urine can help assess concentration. In cats, we expect to see darker urine, which is a sign of the kidneys doing their job to conserve water. Color assessment may also mean looking for the presence of blood (hematuria), myoglobin or hemoglobin. Bilirubinuria, where the pigment bilirubin is abnormally present in the urine, can have a very abnormal brown appearance. The fluid being clear or cloudy indicates if there are a lot of inflammatory cells present or the urine has a lot of mineral sediment.
Any general appearances are confirmed with the dipstick or under the microscope.
2. Urine Concentration
While the general color of urine can provide clues about concentration, we also measure it using a device called a refractometer. A refractometer helps to measure urine concentration compared to the concentration of distilled water, which reads at 1.000. We expect the concentration for a cat to normally be much higher – greater than 1.035.
Urine concentration in cats is a very direct assessment of the kidneys concentrating ability. It is rare for a cat’s urine concentration to drop below the normal concentration without there being concern for reduced kidney function or conditions such as diabetes.
Urine concentration is especially important to compare to bloodwork results looking at kidney function like blood urea nitrogen (BUN), creatinine, and SDMA.
3. Dipstick/Chemical Analysis
The dipstick refers to a strip of plastic that contains several colored testing pads. When they come in contact with urine, the testing pads will change color. The degree of color change can then be compared to a chart that translates the color change to a more objective measurement.
Here are some parameters that a dipstick assesses and what they mean.
Protein
Protein in the urine, called proteinuria, may be seen normally in small amounts in concentrated urine. But seeing protein in higher amounts in more dilute urine can be a concern for underlying kidney disease. Higher protein levels may also be seen with urinary tract infections. A follow up test called a urine protein : creatinine ratio can help determine if the presence of proteinuria is significant or not.
Glucose (Sugar)
Glucose in the urine (called glucosuria) is never a normal finding in a healthy cat’s urine sample and almost always indicates that a cat is diabetic. Some cats with kidney disease may also have trace amounts of glucosuria. I have very rarely seen a cat that was severely stressed during a veterinary visit have a mildly high blood sugar and a trace of glucosuria. Doing a follow-up blood test called a fructosamine can help determine if this was a one-off spike in blood sugar or if diabetes may be truly present.
Ketones
Ketones are a break-down product of fat that occurs when a cat cannot utilize blood sugar. This most often happens with untreated diabetes mellitus and suggests a serious complication called diabetic ketosis is present. Cats of very thin body condition or experiencing starvation may sometimes also have elevated ketones from body fat breakdown.
Blood
The dipstick can tell if blood is present, but not always the significance. Microscopic assessment of the urine is best to get a better picture.
Urobilinogen
Urobilinogen is a product of bilirubin breakdown in the small intestine. Small amounts may be detected in normal urine with high levels being a potential concern for underlying liver or bile duct disease.
Bilirubin
Bilirubin is a yellow pigment that results from the breakdown of red blood cells. This is a normal process in the body, but the liver typically removes it from the body. High bilirubin can be an indicator of either excessive red blood cell breakdown as seen in some immune-mediated anemias or can be a sign of liver dysfunction.
Leukocytes
Leukocytes are white blood cells. Their presence on a urine dipstick is not always accurate, especially in cats, as they are modeled on detecting human white blood cells. Checking for white blood cells under the microscope is always more accurate.
Nitrite
Nitrite is an indicator of a UTI in human urine samples but in urine samples for pets is associated with a very poor correlation and is not considered useful. One reason is because ascorbic acid (vitamin C) that is normally present in pet urine interferes with it.
Ascorbic Acid
Ascorbic acid (vitamin C) is included in urine strips for people because a higher level of ascorbic acid may interfere with some test strip results like nitrite, giving a false negative result if screening for a UTI. In pets, ascorbic acid in urine is a normal finding because dogs and cats’ bodies produce vitamin C. This makes the ascorbic acid pad on a urine strip of no value in pets.
Urine Specific Gravity
The urine specific gravity pad on a test strip has a low degree of accuracy, which is why we always check the USG using the refractometer.
4. Microscope Exam
The final part of a cat urinalysis test is to put part of the urine sample into a centrifuge which spins the urine at a high speed for several minutes. This forces all solid components floating around down to the bottom of the tube. A small sample of this sediment is then collected from the tube, put on a microscope slide, and examined. Here are some things we can see in a urine sediment:
Bacteria
The presence of bacteria in a sterile-collected urine sample is considered abnormal and evidence for a urinary tract infection to be present. We can see a higher proportion of senior cats that have bacteria in their urine without obvious signs of illness, raising the importance of checking a urinalysis at least 1-2 times per year in senior cats.
White Blood Cells/Inflammatory Cells
A small amount of white blood cells in the urine can be normal. But an abnormal amount can be seen with urinary tract infections as well as inflammatory conditions of the urinary tract. Conditions like idiopathic cystitis can have a lot of inflammatory cells present.
Red Blood Cells
Like white blood cells, a small number of red blood cells in a urinary sample may be normal. A veterinarian will have to determine if the presence of blood is significant depending on signs of illness a cat is showing and any concerns with urine collection. Cats with chronic kidney disease may also have at least an intermittent presence of microscopic blood in their urine.
pH
pH is a measure of the acidity or alkalinity of a sample. In dogs and cats, urine pH should be between 6-7.5 on the pH scale. Cats should normally be more on the acidic side owing to a diet higher in protein. A higher urine pH can be seen with some UTIs and a diet lower in protein. Different health conditions may also contribute to a higher or lower pH.
Crystals
Crystals in the urine (called crystalluria) can be significant, especially if a kitty is showing signs of urinary discomfort, straining to urinate, etc. Seeing a layer of sediment in the bladder with an ultrasound also helps to support that crystal presence is abnormal.
But crystals may also be seen in a urine sample that has sat in the fridge overnight, or if a cat is on certain types of medications. Their significance will always be best determined with a fresh urine sample and a veterinarian’s interpretation.
Tissue Cells
Bladder cells may normally be found in small numbers in a urine sample. The bladder is lined with tissue cells and some may dislodge and be viewed in the sample. However, large numbers of cells are considered abnormal. Seeing a thickened bladder wall or tumor with the ultrasound can help determine the significance of tissue cell presence.
Casts are also something that may be seen. Casts are collections of protein surrounding tissue cells and other particles. They develop from the kidney tubules. They can appear more in concentrated urine and acidic urine, so may be seen occasionally in normal cat urine samples. Higher numbers of them can be a concern for kidney disease.
Common Conditions Diagnosed Through Cat Urinalysis
Many conditions involving change in litter box use can be diagnosed through a cat urinalysis test. Axel Bueckert / Shutterstock.com
Urinalysis is usually accompanied by a veterinary examination and often bloodwork as well. However, there are some conditions where a urinalysis can be the cornerstone of diagnosis. These conditions that may be either partially or fully diagnosed through a urinalysis:
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