Testing your cat or dog's urine can help your vet diagnose health conditions and monitor various aspects of their body's function. In this article, our veterinarian in Meadow Vista discusses the purpose of urinalysis for dogs and cats, how urine samples are collected, and what veterinarians look for in each sample.
Why would your veterinarian recommend a urinalysis?
Urinalysis is a diagnostic test that examines urine's physical and chemical properties. Veterinarians primarily perform it to assess the health of the kidneys and urinary system, though it can also detect issues with other organ systems.
We recommend that all senior pets aged eight years or older undergo a yearly urinalysis. We may suggest a urinalysis if your pet exhibits signs such as increased water intake, frequent urination, or visible blood in its urine.
How to collect a pet's urine?
There are three main ways to collect urine from cats and dogs:
Cystocentesis: A sterile needle and syringe are used to collect a urine sample from a pet's bladder. This process, known as cystocentesis, ensures that the urine sample remains unadulterated by debris from the lower urinary tract. It is particularly useful for assessing the bladder and kidneys and detecting bacterial infections. However, veterinarians should note that this procedure, slightly more invasive than other methods, can only be performed when the pet's bladder is full.
Catheterization: Catheterization is a minimally invasive technique for extracting urine from dogs' bladders. It is especially useful when a voluntary sample is not available, particularly in male dogs. The process involves inserting a narrow, sterile catheter into the bladder through the urethra, the lower urinary passage.
Mid-stream Free Flow: A sterile container is held in place while the pet voluntarily urinates, facilitating the collection of a urine sample. This sample type is often called a 'free flow' or 'free catch' sample. This non-invasive method allows pet owners to collect urine samples at home.
What happens during the urinalysis?
There are four main components to a urinalysis for pets:
- 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) in the urine using a microscope.
Your vet will need to examine the sample within 30 minutes of collection. Various factors, such as crystals, bacteria, and cells, can alter the sample's composition. If you collect a urine sample at home, it should be done immediately before heading over to the clinic.
The timing of urine collection is usually insignificant unless we are testing your pet's urine concentration or screening for Cushing's disease. For these specific cases, it is best to collect the urine sample first thing in the morning.
Color & Turbidity
The color of your pet's urine can provide a preliminary indication of its health status. Normally, urine should be pale yellow to light amber and clear to slightly cloudy. Dark yellow urine may indicate dehydration, while orange, red, brown, or black urine could indicate underlying medical conditions.
Increased turbidity or cloudiness in the urine indicates the presence of cells or other solid materials, possibly indicating internal issues.
Concentration of Urine
The concentration of urine refers to its density. In healthy dogs and cats, the kidneys produce dense or concentrated urine. Conversely, dilute or watery pet urine may indicate an underlying medical condition.
When excess water is in the body, the kidneys allow it to pass out in the urine, making it more watery. Alternatively, if insufficient water intake, the kidneys reduce the amount of water lost in the urine, leading to more concentrated urine.
If your pet occasionally passes dilute urine, it may not be a cause for concern. However, if your pet consistently passes watery urine, it may indicate an underlying metabolic or kidney disease. Therefore, it's best to consult a veterinarian for further investigation.
pH & Chemical Composition
The urine pH level, typically between 6.5 and 7.0 in healthy pets, affects its acidity. Abnormal pH levels can facilitate bacterial growth, forming crystals or stones. Consistent abnormal pH levels may require further investigation.
What we Learn from Cells & Solid Material (Urine Sediment)
It is important to examine the urine sediment when conducting a urinalysis. The urine sediment is the material that settles at the bottom of a centrifuged urine sample. Red blood cells, white blood cells, and crystals are the most common in urine sediment.
Free-catch urine samples often contain small amounts of mucus and other debris. Some of the cells that may be present in your pet's urine include:
Red Blood Cells: Your veterinarian may find red blood cells in pets' urine 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: Your vet should not note protein when performing a dipstick test. A positive protein in urine test may indicate a bacterial infection, kidney disease, or blood in the urine.
Sugar: In urine testing, like protein, sugar is another material that should not be present. The presence of sugar in the urine may signal the presence of diabetes mellitus.
Ketones: If your pet's urine tests positive for ketones, the veterinarian will conduct a diabetes mellitus workup. Ketones are abnormal byproducts that your pet's cells produce when they lack an adequate energy source.
Bilirubin: Bilirubinuria indicates that the red blood cells in your pet's bloodstream are being destroyed faster than normal. Pets suffering from liver disease and autoimmune diseases commonly exhibit this finding. 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: The dipstick can detect red blood cells or other blood components, such as hemoglobin or myoglobin, in your pet's urine. Blood in a dog's or cat's urine can indicate an infection, an inflammatory problem, or stones in the bladder or kidney.
Crystals: Crystals can vary in shape and size. Some crystals are unique and can aid in diagnosing a specific condition. In more common conditions like bladder infections, the presence of crystals provides valuable data that can influence treatment decisions for the disease.
Tissue Cells: The presence of bacteria and inflammatory cells in the urine sediment indicates a possible bacterial infection in the urinary system. It is best to send the urine sample to a laboratory for culture and sensitivity testing to determine the specific type of bacteria present and the most effective antibiotic treatment.
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.