Regular urinalysis testing for pets is crucial in detecting various conditions and diseases they may have. Our Concord veterinarians will emphasize the significance of such testing.
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: To collect urine from the bladder, a sterile needle and syringe are used in a technique called cystocentesis. This method ensures that the sample is not contaminated by debris from the lower urinary tract, making it perfect for evaluating the bladder and kidneys, as well as detecting bacterial infections. However, please note that this procedure is slightly more invasive than others and only useful when the pet's bladder is full.
Catheterization: When obtaining a urine sample from a male dog is difficult, catheterization can be a good option. This method involves using a sterile, thin catheter to extract urine from the bladder via the urethra. It's a less invasive approach that can be very effective.
Mid-stream Free Flow: When collecting a urine sample from a pet, it is done voluntarily while they urinate. The sample is then collected in a sterile container. This type of sample is commonly known as a "free flow" or "free catch" sample. This method is advantageous because it doesn't involve any invasive procedures, and pet owners can collect the 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.
It is important to read urine samples within 30 minutes of collection as crystals, bacteria, and cells can affect its composition by dissolving or multiplying. If you collect a urine sample at home, it is recommended that you return it to your veterinary clinic as soon as possible. In most cases, the timing of urine collection is not significant unless we are screening for Cushing's disease or evaluating your pet's ability to concentrate urine. For these specific cases, it is best to take a urine sample 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
Think of concentration as the density of urine. When a kidney is healthy, it produces dense (concentrated) urine. In contrast, watery (dilute) urine in dogs and cats may indicate an underlying disease. If there is an excess of water in the body, the kidneys allow it to pass out in the urine, resulting in more watery or dilute urine.
Conversely, if there is a lack of water, the kidneys reduce the amount of water lost in the urine, leading to more concentrated urine. While the occasional passing of dilute urine by a pet is not necessarily concerning, if it happens consistently, 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. 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: If bilirubinuria is found in your pet's urine test, it may indicate that their red blood cells are being destroyed at a faster than normal rate. This can be caused by liver disease or autoimmune disorders. However, if your pet has blood in their urine due to a bladder infection, it may falsely stain the bilirubin pad on the test, making it seem like there is a more serious liver issue. It's important to consult with a veterinarian to determine the underlying cause and receive appropriate treatment.
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.
When performing a urinalysis, it is important to examine the urine sediment. This refers to the material that settles at the bottom of a centrifuge after spinning a urine sample. The most commonly found elements in urine sediment are red blood cells, white blood cells, and crystals. Additionally, free-catch samples may contain small amounts of mucus and other debris.
Crystals: Numerous types of crystals vary in size, shape, and color. Some crystals are unique and can aid in diagnosing 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 being collected, your veterinarian may want to examine a fresh sample immediately.
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: Although not always indicative of an illness, heightened cellularity is associated with various conditions such as urinary tract inflammation, bladder stones, prostate problems, and cancer. Catheterization samples often contain an increased quantity of tissue cells. If these cells appear unusual, your veterinarian may suggest getting the sediment cytologically prepared to conduct a more detailed analysis of the tissue cells.