Your vet will use diagnostic tests to monitor and diagnose many different conditions and diseases as well as your dog or cat's general health. Here, our vets in Oceanside vets talk about how urinalysis using our veterinary diagnostic laboratory can help to diagnose conditions affecting the urinary system and monitor the function of your pet's internal systems.
What is Urinalysis?
Urinalysis is a veterinary diagnostic test where the urine is collected and examined to gain insight into the health of your pet and developing conditions. It can be used as part of regular preventive care and for diagnosing the cause of specific symptoms.
Why is urinalysis needed for veterinary care?
Your vet will use a urinalysis to detect the overall health of the kidneys and urinary system. This method of diagnostic testing can also be used to diagnose conditions affecting other vital organs like the liver.
What is the method for collecting your pet's urine?
The three ways that your pet's urine may be collected are:
Cystocentesis: This process uses a sterile needle and syringe to puncture the abdominal wall and collect the urine directly from the bladder. This method allows the urine to be collected without possible contamination from debris within the lower urinary passage. Cystocentesis is most commonly used when detecting bacterial infections and other issues with the kidneys and bladder. Unfortunately, this method can only be used when your dog has a full bladder and is cooperative.
Catheterization: This method of urine collection uses a catheter passed through the urethra and up into the bladder to extract urine. This option may be easier than cystocentesis as it is less invasive and easier to use. The downside is the possible irritation that may occur in the urethra and the chance of bacteria moving from the urethra and into the bladder during the process.
Mid-stream free flow: Collecting your dog or cat's urine as they relieve themselves is the easiest method of collection. It is called mid-stream free flow because it is recommended that the urine is collected halfway through their voiding. You can even collect the urine in your own time. There is the possibility, however, that the sample could become contaminated during collection.
What happens during the urinalysis?
When your vet performs a urinalysis on your pet using the equipment and tools in our veterinary diagnostic lab, there will be four main parts to the assessment. They are:
- The assessment of the urine for cloudiness.
- Measuring the concentration of the urine.
- Gauging the acidity or PH of the urine.
- Microscopic examination of the cells and solid material present in the urine.
Most commonly, the vet will take a look at the urine as a whole for the diagnostic evaluation. However, if your vet decides to complete a microscopic examination of the cells and solid material, they will need the urine sample to be concentrated or sedimented. To create a concentrated urine sample, your vet will place the sample of your pet's urine in a tube and run it through the centrifuge at very high speeds. This will cause the heavier materials to move to the bottom of the sample for analysis using a microscope.
How is a urinalysis performed?
A chemical analysis is completed using a dipstick. A dipstick is a small strip of plastic that holds a series of individual test pads. The pads used in the dipstick are designed to change color depending on the concentration of different elements in the urine. The dipstick is dipped into the urine, and after a short waiting period, the color of the test pads is compared to a chart that translates the intensity of the color to an actual measurement.
What will urinalysis show your vet?
- Protein: The presence of protein in urine is called proteinuria. While trace amounts of proteinuria found in concentrated urine may not cause your vet to worry, proteinuria in dilute urine should be considered dangerous since it may indicate kidney disease. The significance of proteinuria is often determined by doing a second test called the protein creatinine ratio test.
- Glucose: Your vet should not find any glucose in your pet's urine. The presence of large amounts of glucose usually indicates your pet has diabetes. Small amounts of glucose in the urine may also be found in pets with kidney disease.
- Ketones: When your pet's body begins to break down stored fats as an energy source, it can result in the presence of ketones. This occurs most frequently in diabetes, but can also be found in healthy animals during prolonged fasting or starvation.
- Blood: If blood is found in the sample, it means that your dog or cat is experiencing bleeding somewhere within their urinary system. Sometimes this is due to how the sample was collected. For example, small amounts of blood are often found in samples collected by cystocentesis or catheterization. Blood in the urine is associated with diseases such as bacterial infection, bladder stones, trauma, or cancer. So if the blood in the urine does not appear to be due to the sampling method, further investigation is recommended.
- Hemoglobin: If your pet has hemolytic anemia, it can result in blood in the urine. Hemolytic anemia is when red blood cells are destroyed and a protein called hemoglobin is released. Hemoglobin passes into the urine and causes the blood test pad to show positive, even though there is no actual bleeding in the urinary system.
- Myoglobin: There is also the chance that blood may be present if your pet is experiencing trauma such as a torn muscle or ligament. This is because damaged muscle fibers release a protein called myoglobin, which is very similar to hemoglobin. Myoglobin will also cause the blood test pad to show positive, even though there is no actual bleeding in the urinary system. A specific test for myoglobin can be done if muscle injury is suspected.
- Urobilinogen: The presence of urobilinogen in urine indicates that the bile duct is open, and that bile can flow from the gallbladder into the intestine.
- Bilirubin: Bilirubin is a substance produced in the liver and normally excreted in the bile. Bilirubin is not found in the urine of healthy cats but may be found in small quantities in the urine of healthy dogs. Abnormal amounts of bilirubin in the urine are associated with liver disease or red blood cell destruction (called hemolysis), and should always be investigated.
Using Urinalysis to Exam Your Pet's Urine Sediment
While using a dipstick can provide a lot of information about your pet's health, it does not reveal the whole picture. Your vet may also perform a microscopic examination of the urine sediment to gain even more insight. In order to examine the urine sediment, your vet will use a centrifuge in our veterinary diagnostic laboratory in Oceanside to separate the different parts of the urine sample.
What We May Find in Abnormal Urine Sediment
White Blood Cells: These can indicate that there may be an issue in the bladder or kidneys of your pets.
Red Blood Cells: If red blood cells are found then your pet may be experiencing trauma or irritation to the bladder or kidneys. Some of the conditions that red blood cells may be a sign of include:
- Bladder or kidney infections
- Bladder or kidney stones
- Interstitial cystitis (inflammation within the lining of the bladder)
- Cancer within the urinary tract system
Bacteria: Bacteria is the most obvious sign that your dog or cat is experiencing an infection within the urinary system. In cases where bacteria are not present yet there are clinical signs of a urinary tract infection then your vet may request a urine culture be performed.
Casts: If a pet is experiencing damage to one of their kidneys then their body may 'shed' the lining within the tiny tubes that make up the tissue within the kidneys. If these casts are found then your vet will request further diagnostic testing using the pet laboratory.
Crystals: While the pH of your pet's urine will likely stay within the normal range most of the time, there may the situations that result in the pH going into abnormal ranges allowing for the development of crystals. At times these crystals can be resolved naturally without causing further issues. If your vet notices an abnormally large number of crystals they may recommend a radiograph (X-ray) or ultrasound of your pet’s abdomen to look for bladder or kidney stones.
Other Cells: Vets may witness abnormal cells in pets that have developed tumors. If your pet is experiencing irritated bladder walls they may shed cells into the urine which are called transitional epithelial cells.
Urine samples performed in our veterinary diagnostic laboratory in Oceanside, are a crucial part of diagnosis for both determining the cause of particular symptoms and monitoring your cat or dog's ongoing health and bodily function.
Note: The advice provided in this post is intended for informational purposes and does not constitute medical advice regarding pets. For an accurate diagnosis of your pet's condition, please make an appointment with your vet.