At Bruceville Pet Hospital, we strongly believe in educating so their pets can stay healthy and happy for as long as possible. Here, our Elk Grove vets discuss urinalysis for dogs and cats, along with how to understand your pet's urinalysis results so you can make the best choices regarding their medical care.
What is a Urinalysis for Pets?
This simple diagnostic test determines a urine sample's physical and chemical properties. Primarily used to evaluate the health of your pet's urinary system and kidneys, a urinalysis can be completed for dogs or cats. It may also reveal issues with other organ systems.
All pets eight years of age or older should have an annual urinalysis. Your vet may also recommend the test if your pet has increased frequency of urination, increased water intake, or visible blood in their urine.
How is Urine Collected?
Here are three common ways to collect urine from cats and dogs:
Mid-Stream Free Flow: The sample is collected into a sterile container as your pet urinates voluntarily. Frequently referred to as a "free catch" or "free flow" sample, this method is completely non-invasive and the pet owner will be able to collect the urine sample at home.
Cystocentesis: A sterile needle and syringe are used to collect urine from the bladder. The benefit of cystocentesis that debris from the lower urinary tract will not contaminate the urine. This type of sample is ideal for evaluating the kidneys and bladder, along with detecting a bacterial infection. Note that this procedure is slightly more invasive than others and is only useful if your pet's bladder is full.
Catheterization: As a less invasive method of extracting urine from the bladder in dogs, catheterization is a good 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 (the urethra).
Understanding the Results of a Urinalysis
There are four main components to a urinalysis?
- Check appearance: Color and turbidity (cloudiness).
- Measure the concentration (also referred to as density) of the urine.
- Measure pH (acidity) and analyze the urine's chemical composition.
- Examine cells and solid material (urine sediment) in the urine using a microscope.
Urine samples should be analyzed within 30 minutes of collection since other factors (such as bacteria, cells and crystals) can change the composition (multiply or dissolve). If you collect a urine sample at home, please bring it to your veterinary clinic as soon as possible.
Unless we are assessing a pet's ability to concentrate urine or screening for Cushing's disease, the actual timing of urine collection is typically insignificant. However, if we are screening for Cushing's disease or evaluating your pet's ability to concentrate urine, a urine sample should be taken first thing in the morning.
Color & Turbidity
Urine that ranges from pale yellow to light amber in color and is clear to slightly cloudy. Dark yellow urine usually indicates that the pet needs to drink more water or is dehydrated. Urine that is not yellow (for example, orange, red, brown, or black) may contain substances that are not normally found in healthy urine and could indicate an underlying health issue.
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.
Concentration
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 there is an excess of water in the body, the kidneys allow it to pass out in the urine, making the urine more watery or dilute. If water is deficient, the kidneys reduce the amount of water lost in the urine, making it more concentrated.
If your pet passes dilute urine from time to time, it is not necessarily a cause for concern. If dilute urine is continuously found in a dog's or cat's urinalysis, 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 caused for concern. If it is consistently abnormal, your veterinarian may wish to investigate further.
Cells & Solid Material (Urine Sediment)
Some of the cells present in the urine can include:
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: If a urinalysis of your dog's or cat's urine reveals blood, this may 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.
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.
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.
Crystals: There are numerous types of crystals that 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.
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.