Your veterinarian might conduct additional tests to assess your dog's health. One of these tests is urinalysis, which our vets at Grants Pass explain in detail. They discuss why urinalysis is recommended for your dog and provide insights on how this diagnostic method is performed.
What is a urinalysis?
A urinalysis is a diagnostic test used by your vet to examine the physical and chemical properties of your dog's urine. Its main purpose is to assess the health of their kidneys and urinary system, although it can also detect potential issues with other systems and organs in their body. Urinalysis plays a vital role in the ongoing preventive care for your dog.
How is Your Dog's Urine Collected for Urinalysis?
Your vet will utilize one of three main ways to collect your dog's urine.
Cystocentesis: In this process, a sterile needle and syringe are used to collect urine from your dog's bladder by puncturing the abdominal wall directly. This method ensures that the urine is collected without any contamination from debris in the lower urinary passage. Cystocentesis is commonly used to detect bacterial infections and other kidney and bladder issues. However, it can only be done when your dog has a full bladder and is cooperative, making it a more intrusive method of collecting urine.
Catheterization: This urine collection method involves inserting a catheter through the urethra into the bladder. A syringe is then attached to withdraw the urine. Compared to cystocentesis, this option is less invasive and more user-friendly. However, there are potential drawbacks, such as potential irritation in the urethra and the risk of bacteria moving from the urethra to the bladder.
Mid-stream free flow: The simplest way to collect urine from your dog is when they are willingly urinating. It is best to collect the urine midway through the process. This method is also known as free-flow or free-catch. It allows you to collect the urine at your convenience. However, there is a chance of contamination during the collection process.
How Will Your Vet Perform Your Dog's Urinalysis?
Urinalysis happens in four parts:
- Your vet will assess the cloudiness of the urine.
- They will measure the concentration of your dog's urine.
- Your vet will determine the acidity or PH of the urine.
- They will utilize a microscope to explore the cells and solid material present in the urine.
Your vet will mostly analyze the entire urine sample collected. However, they will need a concentrated urine sample if they want to examine the cells and solid materials under a microscope. To create a concentrated sample, your vet will place your dog's urine in a tube and spin it at high speeds in a centrifuge. This process separates the heavier materials, which settle at the bottom of the tube. The concentrated sample obtained will be further analyzed using a microscope.
How is the Chemical Analysis of Your Dog's Urine Performed?
In urine analysis, a dipstick is used. It's a small plastic strip containing several test pads. Each pad measures a different chemical in the urine and changes color accordingly. By dipping the dipstick into the urine and waiting briefly, the color of the test pads can be compared to a chart. This chart helps determine the exact measurement based on the color intensity.
What Substances Will be Detected by the Chemical Analysis of Your Dog's Urine?
- Protein: The presence of protein in urine is called proteinuria. Mild proteinuria in concentrated urine may not be a cause for concern, but proteinuria in dilute urine should be investigated since it may signal developing kidney disease. The significance of proteinuria is often determined by doing a second test called the protein: creatinine ratio.
- Glucose: Glucose should not be present in the urine of healthy cats and dogs. The presence of large amounts of glucose usually indicates the pet has diabetes mellitus. Small amounts of glucose in the urine may also be found in pets with kidney disease.
- Ketones: Ketones appear in urine whenever the body breaks down excessive amounts of stored fat to meet its energy needs. This occurs most frequently in diabetes mellitus, but can also be found in healthy animals during prolonged fasting or starvation.
- Blood: Blood in the urine usually indicates there is bleeding somewhere in the 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 further investigation is recommended if the blood in the urine does not appear to be due to the sampling method.
Sometimes, a positive result for blood on a blood test can be due to a condition called hemolytic anemia. In this condition, red blood cells are destroyed, and a protein called hemoglobin is released. The hemoglobin enters the urine and causes the blood test to show a positive result, even though there is no actual bleeding in the urinary system.
There are instances when the blood test may show a positive result for blood due to muscle inflammation or injury. This happens because damaged muscle fibers release a protein called myoglobin, which is similar to hemoglobin. Even though there is no actual bleeding in the urinary system, myoglobin can still cause the blood test to show a positive result. If there is suspicion of muscle injury, a specific test for myoglobin can be performed.
- Urobilinogen: The presence of urobilinogen in urine indicates that the bile duct is open, and that bile can flow from the gall bladder into the intestine. A negative urobilinogen result has no interpretation and does not mean the bile duct is obstructed.
- Bilirubin: Bilirubin is a substance that is 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.
What is the Benefit of Examining Your Dog's Urine Sediment?
Urine sediment refers to the substances that settle at the bottom of a tube when a urine sample is spun in a centrifuge. Common components of urine sediment include red blood cells, white blood cells, crystals, bacteria, and tissue cells from various parts of the urinary system.
Free-catch samples may also contain small amounts of mucus and miscellaneous debris. In rare cases, urine sediment may contain parasite eggs.
- Red Blood Cells. Small numbers of red blood cells are often found in urine collected by cystocentesis or catheterization, but large numbers of red blood cells usually indicate bleeding. This may be caused by conditions such as bladder stones, infection, coagulation problems, trauma, cancer, etc.
- White Blood Cells. Small numbers of white blood cells in a free-catch sample may not be significant, but in general, an increased number of white blood cells indicates inflammation somewhere in the urinary system. Inflammation is often secondary to bacterial infection.
- Bacteria. The presence of both bacteria and inflammatory cells in the sediment indicates there is likely bacterial infection somewhere in the urinary system. Ideally, the urine should be sent to the laboratory for culture and sensitivity testing to find out what types of bacteria are present and which antibiotic should be used to treat the infection.
- Crystals. There are many different types of crystals and they vary in size, shape, and color. The significance of crystals also varies. Some crystals are unique and help to pinpoint a specific diagnosis. In more common conditions such as bladder infection and bladder stones, the crystals provide information that can influence how the disease is managed.
Crystals in the urine do not always indicate disease. Some crystals form when a pet is given certain types of medications. Crystals can also form in urine after it has been collected, especially if there is a long delay before the urinalysis is done. If this happens, your veterinarian may wish to examine a fresh sample immediately after it has been collected to determine if the crystals are significant.
- Tissue Cells. Increased numbers of tissue cells are often seen in samples collected by catheterization. While this is not a sign of disease, increased cellularity can be seen with a variety of disorders, including urinary tract inflammation, bladder stones, prostate problems (in the male dog), cancer etc. If the cells look abnormal, your veterinarian may recommend a cytological preparation of the sediment, which allows for a more detailed examination of the tissue cells.
Is your dog due for a regular check-up? Reach out to our veterinary team at Lincoln Road Veterinary Clinic in Grants Pass to book an appointment for your furry friend today.
