Pet owners can get expert guidance from veterinarians to care for their animals. Today, our Harlingen vets will discuss urinalysis for dogs and cats and how to understand your pet's urinalysis results.
What is an Urinalysis?
A urinalysis is a simple diagnostic test that determines urine's physical and chemical properties. It is primarily used to evaluate the health of the kidneys and urinary system, but it can also reveal issues with other organ systems. All pets eight years of age and older should have a yearly urinalysis. A urinalysis may also be recommended as a wellness examination if your pet has increased water intake, increased frequency of urination, or visible blood in the urine.
How is Urine Collected?
There are three ways to collect urine from cats and dogs:
Catheterization: This is a less invasive method of extracting urine from the bladder in dogs and is an excellent choice when a voluntary sample is unavailable, particularly in male dogs. It involves inserting a narrow sterile tube into the bladder through the lower urinary passage (called the urethra).
Cystocentesis: This method collects urine directly from the bladder using a sterile needle and syringe. It's great for clean samples without lower urinary tract debris, making it useful for evaluating the bladder and kidneys as well as detecting bacterial infections. The procedure is slightly more invasive than others and is only useful if the pet's bladder is full.
Mid-stream Free Flow: The pet urinates voluntarily, and a sample is collected into a sterile container as the pet urinates. This type of sample is frequently referred to as a "free flow" or "free catch" sample. The benefits of this method include the fact that it is completely non-invasive and that the pet owner can collect the urine sample at home.
Understanding the Results of a Urinalysis
There are four main parts to a urinalysis:
- Assess appearance: color and turbidity (cloudiness).
- Measure the concentration (also known as the density) of the urine.
- Measure pH (acidity) and analyze the chemical composition of the urine.
- Examine the cells and solid material (urine sediment) present in the urine using a microscope.
For accurate analysis, urine samples should be examined within 30 minutes of collection since various factors like crystals, bacteria, and cells can modify the composition by dissolving or multiplying. If you collect a urine sample at home, please promptly return it to your veterinary clinic.
In most cases, the exact timing of urine collection isn't crucial unless we're specifically checking your pet's urine concentration or screening for Cushing's disease. If we are conducting screenings for Cushing's disease or evaluating your pet's ability to concentrate urine, it is recommended to obtain a urine sample in the early morning.
Healthy urine should typically be light yellow and look clear or slightly cloudy. Dark yellow urine often indicates the need for increased water intake or dehydration in pets. If the urine is a different color, like orange, red, brown, or black, it might have unusual things in it, which could be a sign of a health problem.
Elevated turbidity or cloudiness in urine signifies the presence of cells or solid materials. This turbidity intensifies when there is blood, inflammatory cells, crystals, mucus, or debris in the urine. The sediment within the urine sample will be carefully analyzed to identify its constituents and determine its clinical significance.
The concentration of urine means how thick or thin it is. A healthy kidney makes thick urine, while dogs and cats with thin urine might have a health problem.
When there is an excess of water in the body, the kidneys allow it to be eliminated through urine, resulting in a more watery or dilute urine. Conversely, if there is a shortage of water, the kidneys conserve water and produce more concentrated urine.
Sometimes, pets can have thin urine now and then, and it's not a big worry. But if a pet often has thin urine, it might have a kidney or health issue that needs checking.
The acidity of urine depends on it's pH level. In healthy pets, the urine pH typically falls within the range of 6.5 to 7.0. When the pH is too acidic or too alkaline, it creates an environment where bacteria can flourish, and the risk of crystal or stone formation increases. It is important to note that normal variations in urine pH can occur throughout the day, especially after consuming certain foods or medications.
If one urine pH test shows a value outside the normal range, but the rest of the urine test looks fine, there's usually no need to worry right away. However, if the pH consistently remains abnormal, your vet may want to investigate further to find any underlying issues.
Some of the cells present in the urine can include:
Red Blood Cells: Red blood cells may indicate bladder wall or kidney trauma or irritation. The technician will find red blood cells in the urine in pets with bladder or kidney infections, bladder stones, or interstitial cystitis. It may also be an early sign of cancer of the urinary tract.
White Blood Cells: White blood cells could indicate an infection or an inflammatory process in the bladder or kidney.
Protein: Protein should not be found in urine on a dipstick test. A positive protein in urine test may indicate a bacterial infection, kidney disease, or blood in the urine.
Sugar: Urine should not contain any sugar. The presence of sugar in the urine may signal the presence of Diabetes mellitus.
Ketones: If your pet tests positive for ketones in its urine, a Diabetes Mellitus workup will be performed. Ketones are abnormal byproducts that your pet's cells produce when they lack an adequate energy source.
Bilirubin: Bilirubinuria is an abnormal finding indicating that red blood cells in your pet's bloodstream are being destroyed faster than normal. It has been found in pets suffering from liver disease and autoimmune diseases. Remember that pets with blood in their urine due to a bladder infection can falsely stain the bilirubin pad on the dipstick, raising the possibility of a more serious liver problem.
Urobilinogen: Urobilinogen in urine indicates that the bile duct is open and bile can flow from the gallbladder into the intestine.
Blood: Blood in a dog's or cat's urine can indicate an infection, an inflammatory problem, or stones in the bladder or kidney. The dipstick can detect red blood cells or other blood components, such as hemoglobin or myoglobin, in your pet's urine.
Crystals: Numerous types of crystals vary in size, shape, and color. Some crystals are one-of-a-kind and can aid in the diagnosis of a specific condition. In more common conditions, such as bladder infections, the crystals provide data that can influence how the disease is treated. Because crystals can form in urine after it has been collected, your veterinarian may want to examine a fresh sample right away.
Bacteria: The presence of bacteria, as well as inflammatory cells in the sediment, suggests that there is a bacterial infection somewhere in the urinary system. The urine should ideally be sent to a laboratory for culture and sensitivity testing to determine what types of bacteria are present and which antibiotic should be used to treat the infection.
Tissue Cells: While not necessarily a sign of disease, increased cellularity has been linked to several conditions, including urinary tract inflammation, bladder stones, prostate issues, and cancer. Catheterization samples frequently contain an increased number of tissue cells. If the cells appear abnormal, your veterinarian may advise you to have the sediment cytologically prepared. This enables a more in-depth examination of the tissue cells.