Diagnostic testing is crucial to the health of pets. Tests such as urinalysis can help to ensure that their internal systems are functioning as they should be. Here, our Crystal Lake vets share some information about what to expect when you bring your dog in for a urinalysis and what we learn from this test.
What is urinalysis used for with dogs?
A urinalysis is a form of testing completed using equipment in a vet diagnostic lab to test the physical and chemical properties of urine. This can be used as part of regular preventive care and in the case of diagnosing the cause of specific symptoms.
Why is urinalysis a crucial part of veterinary care?
Your vet will use urinalysis to determine the overall health of the kidneys and urinary system. It may also be used to determine issues in other organs and systems such as metabolic diseases like diabetes mellitus.
How does a vet collect the urine for urinalysis?
There are three different ways that your vet may collect your pet's urine sample:
Cystocentesis: This process utilizes a sterile needle and syringe as the method of collecting urine from your dog's bladder by puncturing the abdominal wall and collecting 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 which can be difficult as it is a more intrusive method of collecting urine.
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 easier to utilize. The downside is the possible irritation that may occur within 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 likely 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. Other terms for this method of collection are free-flow or free-catch. This way of collecting the urine sample is easiest as you can do the collecting in your own time. There is the possibility however that the sample could become contaminated during collection.
What are the different parts of urinalysis?
There are four distinct parts of urinalysis, 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.
Generally, the urine will be examined as a whole specimen just as it was collected. 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. In order to create a concentrated urine sample, your vet will place the sample of your dog's urine in a tube and then run it through the centrifuge at very high speeds which will cause the heavier materials to move to the bottom of the sample and this sample will then be analyzed using a microscope.
What is a chemical analysis and how is it performed?
A chemical analysis is used to show the chemical components of your dog's urinalysis. This test is completed using a tool known as a dipstick which 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.
Substances That May be Found in Your Dog's Urine
- 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 since it may indicate kidney disease. The significance of proteinuria is often determined by doing a second test called the protein: creatinine ratio.
- Glucose: Your vet should not find any glucose in the urine of your pet. 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: 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 mellitus, 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 a condition known as 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 companion 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 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 makes up the urine sediment?
The urine sediment is separated using a centrifuge. The urine sample will be placed in the centrifuge where it will then be soun at a high speed. During this process, any solid particles will be forced to the bottom of the sample. These particles are commonly referred to as sediment.
Urine sediment is commonly made up of red blood cells, white blood cells, crystals, bacteria, and tissue cells from different parts of the urinary system. There may be small amounts of other particles including mucus, present in this sediment. Your vet may even discover parasitic 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.
Urinalysis at our Clinic in Crystal Lake
Your vet will use urinalysis to monitor the health of your dog and provide insight into the function of their organs. If you would like to learn more about urinalysis and other tests performed in our veterinary diagnostic laboratory, please feel free to reach out to our team.
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.