Your vet may conduct additional tests to assess your dog's health. One diagnostic method they might use is urinalysis. In this article, our Fort Pierce vets explain why they may recommend urinalysis for your dog and detail how they perform this diagnostic testing in the veterinary laboratory.
What is a urinalysis?
The vet lab at the clinic will conduct a urinalysis, a diagnostic test that assesses urine's physical and chemical properties. Your vet will use this test to evaluate the health of your dog's kidneys and urinary system. Additionally, it can reveal potential concerns with other systems and organs in your dog's body. Urinalysis is a crucial diagnostic tool for ensuring the ongoing preventive care of your dog.
How is Your Dog's Urine Collected for Urinalysis?
Your vet will utilize one of three ways to collect your dog's urine.
Cystocentesis: This process involves using a sterile needle and syringe to collect urine directly from your dog's bladder by puncturing the abdominal wall. This method ensures urine is collected without potential contamination from debris in the lower urinary passage. Veterinarians commonly employ cystocentesis to detect bacterial infections and other kidney and bladder issues. However, it can only be performed when your dog has a full bladder and is cooperative, making it challenging due to its more intrusive nature.
Catheterization: This method of urine collection uses a catheter passed through the urethra and up into the bladder, which then has a syringe attached to extract the urine from the bladder. This option may be easier than cystocentesis as it is less invasive and more accessible to utilize. The downside is the possible irritation within the urethra and the chance of bacteria moving from the urethra and into the bladder during the process.
Mid-stream free flow: Collecting urine from your dog is simplest when they willingly empty their bladder. It's advisable to gather the urine midway through their voiding. This method is also known as free-flow or free-catch. Opting for this approach allows you to collect the sample at your convenience. However, be aware that there is a risk of sample 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 generally analyze the entire urine sample collected. However, if a microscopic examination of cells and solid material is required, your vet will need the urine sample to be concentrated or sedimented. To create a concentrated urine sample, your vet will place your dog's urine in a tube and then use a centrifuge at high speeds. This process causes heavier materials to move to the bottom of the sample, and the resulting concentrated sample will be examined under a microscope.
How did the chemical analysis of your dog's urine Perform?
We analyze urine chemically using a dipstick—a small plastic strip with individual test pads. Each pad measures a specific chemical component, changing color to show the substance amount in the urine. Dip the strip into the urine, wait briefly, and then compare the test pad colors to a chart that translates color intensity into measurements.
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 the development of 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. Large amounts of glucose usually indicate 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 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.
A positive reading for blood can also be seen with a disease called hemolytic anemia, in which 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 bleeding in the urinary system.
Occasionally, the blood test pad will show positive for blood when there is muscle inflammation or injury. This is because damaged muscle fibers release a protein called myoglobin, which is similar to hemoglobin. Myoglobin will also cause the blood test pad to show positive, even though there is no 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 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 is the material that settles at the bottom of the tube when a centrifuge spins a urine sample. This sediment commonly contains red blood cells, white blood cells, crystals, bacteria, and tissue cells from various urinary system parts.
Free-catch samples often contain small amounts of mucus and miscellaneous debris; on rare occasions, urine 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. Still, 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 determine 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 develop 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.
Veterinary Pet Pharmacy
The in-house pet laboratory clinic at Sunrise City Animal Hospital offers various diagnostic testing options. Additionally, some clinics provide veterinary pharmacies onsite, enhancing their ability to serve their patients better.