Urinalysis for Pets
A urinalysis determines the chemical and physical properties of urine. This simple diagnostic test is used to evaluate the health of the kidneys and urinary system. However, it can also reveal issues with other organs.
All senior pets eight years of age and older should have an annual urinalysis. Your veterinarian may also recommend this test if your pet has increased frequency of urination, increased water intake, or visible blood in the urine.
Collecting a Urine Sample
There are three ways to collect a urine sample from cats and dogs:
Cystocentesis - A sterile needle and syringe are used to collect urine from the bladder. One advantage of cystocentesis is that the urine is not contaminated by debris from the lower urinary tract. This sample is ideal for evaluating the kidneys and bladder, along with detecting bacterial infection. This procedure is slightly more invasive than others and is only useful if your pet's bladder is full.
Catheterization - A less invasive method of extracting urine from the bladder, catheterization is an excellent option when a voluntary sample is unavailable, particularly in male dogs. A very narrow sterile catheter is inserted into the bladder through the urethra (the lower urinary passage).
Mid-Stream Free Flow - The sample is collected when your pet urinates voluntarily into a steel container. Frequently referred to as a "free flow" or "free catch" sample, this method is completely non-invasive and can be collected at home.
Understanding the Results of Your Pet's Urinalysis
There are four main parts to a urinalysis:
- Assess appearance, including color and turbidity (cloudiness).
- Measure the concentration (also referred to as the density) of the urine.
- Measure pH (acidity) and analyze the urine's chemical composition.
- Examine the cells and solid material 9urine sediment) present in the urine using a microscope.
Because other factors (including bacteria, cells, and crystals) can alter the composition (dissolve or multiply) of urine, samples should be read within 30 minutes of collection. If you collect a urine sample at home, please bring it to your veterinary clinic as soon as possible.
Unless we are evaluating your pet's ability to concentrate urine or screening for Cushing's disease, the actual timing of urine collection is usually insignificant. However, if we are screening for Cushing's disease or evaluating your pet's ability to concentrate urine, the sample should be taken first thing in the morning.
Color & Turbidity
A healthy cat's or dog's urine should range from pale yellow to light amber in color. It may be clear or slightly cloudy. Dark urine usually points to dehydration and indicates your pet needs to drink more water. Urine that is any color other than yellow may contain substances not normally found in healthy urine, and may indicate an underlying health condition.
Increased cloudiness or turbidity in the urine indicates the presence of cells or other solid material. If blood, crystals, debris, inflammatory cells, or mucus are present, turbidity will increase. Your pet's sample will be examined in a lab to determine its composition and whether it is significant.
Think of concentration as the density of the urine. While a healthy kidney produces dense or concentrated urine, an underlying disease can cause the kidney to produce watery (dilute) urine in cats and dogs.
If your pet has an excessive amount of water in their body, the kidneys allow it to pass out in the urine, making the urine watery or more dilute. If water is deficient, the kidneys reduce the amount of water being lost in the urine, resulting in more concentrated urine.
If a dog or cat occasionally produces dilute urine, it's 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 a cause 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 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 cats or dogs 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 cat or dog'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.
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 from your pet 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. Your pet's 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 people or pets. If you are concerned about your pet's health, contact your veterinarian right away for diagnosis and treatment.