A urinalysis test can help detect several conditions and diseases that your cat or dog may have. Today, our San Diego vets discuss the importance of regular urinalysis testing for pets.
Urinalysis for Pets
A urinalysis is a simple diagnostic test that determines the physical and chemical properties of urine. 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 senior pets eight years of age and older should have a yearly urinalysis. A urinalysis may also be recommended if your pet has increased water intake, increased frequency of urination, or visible blood in the urine.
Collecting a Urine Sample
There are three main ways to collect urine from cats and dogs:
Cystocentesis: Using a sterile needle and syringe, urine is drawn from the bladder. The advantage of cystocentesis is that it prevents lower urinary tract debris from contaminating the urine. This sample is perfect for diagnosing bacterial infection as well as evaluating the bladder and kidneys. The procedure is only beneficial if the pet's bladder is full and is a little more invasive than others.
Catheterization: Catheterization 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. A very narrow sterile catheter is inserted into the bladder through the lower urinary passage (called the urethra).
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 a 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.
Samples of urine should be read within 30 minutes of collection because other elements (like crystals, bacteria, and cells) can change the composition (dissolve or multiply). If you take a urine sample at home, send it back to the veterinary clinic as soon as you can. The precise timing of urine collection is typically unimportant unless we are testing for Cushing's disease or assessing your pet's capacity to concentrate urine. However, we need a urine sample taken as soon as the sun rises if we're checking for Cushing's disease or assessing your pet's capacity to concentrate urine.
Color & Turbidity
Urine that is clear to slightly cloudy, and ranges in color from light amber to pale yellow. The pet either needs to drink more water or is dehydrated, according to the typical signs of dark yellow urine. Not yellow urine (orange, red, brown, or black, for example) may contain substances that are not typically found in healthy urine and may be a sign of a more serious health problem.
Increased turbidity or cloudiness in the urine indicates the presence of cells or other solid materials. Turbidity increases when there is blood, inflammatory cells, crystals, mucus, or debris present. The sediment will be examined to determine what is present and whether it is significant.
Consider concentration to be the density of the urine. A healthy kidney produces dense (concentrated) urine, whereas watery (dilute) urine in dogs and cats may indicate underlying disease.
If the body has too much water, the kidneys allow it to pass out in the urine, making the urine more watery or dilute. When there is a lack of water, the kidneys reduce the amount of water lost in urine, making it more concentrated.
If a dog or cat passes dilute urine from time to time, it is not necessarily a cause for concern. If a pet continuously passes dilute urine, there may be an underlying kidney or metabolic disease that requires further investigation.
pH & Chemical Composition
The pH level of the urine indicates its acidity. The pH of urine in healthy pets is usually between 6.5 and 7.0. If the pH is acidic (pH less than 6) or alkaline (pH greater than 7), bacteria can thrive and crystals or stones can form.
Normal variations in urine occur throughout the day, especially when certain foods and medications are consumed. If the rest of the urinalysis is normal, a single urine pH reading is not cause for concern. If it is consistently abnormal, your veterinarian may want to look into it further.
Cells & Solid Material (Urine Sediment)
Some of the cells present in your pet's urine can include:
Red Blood Cells: Red blood cells may indicate bladder wall or kidney trauma or irritation. In pets with bladder or kidney infections, bladder stones, or interstitial cystitis, the technician will find red blood cells in the urine. 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 that indicates that red blood cells in your pet's bloodstream are being destroyed at a faster than normal rate. 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.
Sediment: Urine sediment should also be examined when conducting a urinalysis. Urine sediment is the material that settles to the bottom of a centrifuge after spinning a urine sample. Red blood cells, white blood cells, and crystals are the most common things found in urine sediment. Small amounts of mucus and other debris are frequently found in free-catch samples.
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: 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 allows for a more in-depth examination of the tissue cells.