Regular urinalysis testing for pets is crucial in detecting various conditions and diseases they may have. Our vets at O’Fallon explain the significance of this diagnostic test.
Urinalysis for Pets
A urinalysis is a basic medical test that examines the physical and chemical characteristics of urine. Its primary purpose is to assess the health of the urinary and kidney systems, although it can also identify potential problems with other organs.
For senior pets aged eight years and above, it's advisable to conduct a urinalysis annually. It may also be necessary to perform a urinalysis if your pet consumes more water than usual, urinates more frequently or if there is visible blood in their urine.
Collecting a Urine Sample
There are three primary methods for collecting urine from cats and dogs:
Cystocentesis: To collect urine from the bladder, a sterile needle and syringe are used through a process called cystocentesis. This method has the advantage of ensuring that the urine sample is not contaminated by debris from the lower urinary tract. It is a highly effective means of evaluating the bladder and kidneys, as well as detecting bacterial infection. However, it should be noted that this procedure is slightly more invasive than other methods and is only recommended if the pet's bladder is full.
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: To collect a urine sample from a pet, it is important to let them urinate voluntarily. The sample should be collected in a sterile container during the process, which is commonly known as a "free flow" or "free catch" sample. This method is non-invasive and can be done easily by pet owners within the comfort of their homes.
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's important to read urine samples within 30 minutes of collection to prevent external factors like crystals, bacteria, and cells from changing the composition. When collecting a urine sample at home, it's best to return it to your veterinary clinic as soon as possible. The urine collection timing is generally insignificant unless we're screening for Cushing's disease or evaluating your pet's ability to concentrate urine, in which case, a morning urine sample is preferred.
Color & Turbidity
It's normal for your pet's urine to be pale yellow to light amber in color and clear to slightly cloudy. However, if the urine is dark yellow, it could mean that your pet is dehydrated and needs to drink more water. Additionally, if the urine has an unusual color like orange, red, brown, or black, it may be a sign of an underlying health issue.
If the urine appears more cloudy or opaque than usual, it could be an indication of the presence of cells or other solid materials. Blood, inflammatory cells, crystals, mucus, or debris can cause this. It's important to have the sediment examined to determine what's causing the increased turbidity and whether it's significant.
Think of concentration as the density of your urine. When a kidney is healthy, it produces dense and concentrated urine. However, if your urine is watery and dilute, it may be an indication of an underlying disease in dogs and cats. If there is an excess of water in your body, the kidneys allow it to pass out in the urine, resulting in a more watery or dilute urine.
On the other hand, if there is a deficiency of water, the kidneys reduce the amount of water lost in the urine, making it more concentrated. If your pet passes dilute urine occasionally, there is no need for concern. However, if your pet continuously passes dilute urine, it may be an indication of an underlying kidney or metabolic disease that requires further investigation.
pH & Chemical Composition
The acidity of urine can be determined by its pH level, which should typically fall between 6.5 and 7.0 for healthy pets. If the pH is too acidic (less than 6) or too alkaline (greater than 7), it can create an environment where bacteria can thrive and crystals or stones may form. It's important to note that urine pH can vary throughout the day due to factors such as food and medication intake. If there are no other abnormalities in the urinalysis, a single pH reading should not cause alarm. However, if there is consistent abnormality, further investigation by a veterinarian may be necessary.
Cells & Solid Material (Urine Sediment)
Your pet's urine may contain various types of cells, such as:
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: 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.
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: 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.