We at Lafayette Companion Animal Hospital strongly believe in educating our clients to help them be the best pet owners they can be. In order to help you make the best choices for your pet's medical care, our Boulder County veterinarians will talk to you today about urinalysis for dogs and cats as well as how to interpret your pet's urinalysis results.
Why Would My Vet Recommend a Urinalysis?
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 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.
How is Urine Collected?
There are three main ways to collect urine from cats and dogs:
Cystocentesis: Using a sterile needle and syringe, urine is drawn from the bladder. The advantage of cystocentesis is that it prevents lower urinary tract debris from contaminating the urine. This sample is perfect for diagnosing bacterial infection as well as evaluating the bladder and kidneys. The procedure is only beneficial if the pet's bladder is full and is a little more invasive than others.
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: The animal urinates voluntarily, and as it does so, a sample is taken and placed in a sterile container. The terms "free flow" and "free catch" are frequently used to describe this kind of sample. This approach has the advantages of being completely non-invasive and allowing the pet owner to collect the urine 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.
Since other factors (like crystals, bacteria, and cells) can change the composition of urine samples, they should be read within 30 minutes of collection (dissolve or multiply). Please send any urine samples you collect at home to your local veterinary clinic as soon as you can. The precise timing of urine collection is typically unimportant unless we are assessing your pet's capacity to concentrate urine or performing a Cushing's disease screening. However, we need a urine sample taken first thing in the morning if we are checking for Cushing's disease or assessing your pet's capacity to concentrate urine.
Color & Turbidity
Urine that is clear to slightly cloudy, and ranges in color from pale yellow to light amber. Dark yellow urine typically indicates that the animal is either dehydrated or needs to drink more water. A health problem may be present if the urine is orange, red, brown, or black in color rather than yellow. Such urine may contain substances that are not typically found in healthy urine.
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.
The kidneys permit extra water in the body to be expelled in the urine, which causes the urine to become more watery or diluted. When there is a lack of water, the kidneys increase the concentration of urine by reducing the amount of water lost in the urine.
If a dog or cat passes dilute urine from time to time, it is 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 urine's pH level reveals how acidic it is. Healthy pets typically have urine with a pH of 6.5 to 7.0. Bacteria can flourish and crystals or stones can form in an acidic (pH less than 6) or alkaline (pH greater than 7) environment. Throughout the day, urine typically varies, especially after taking certain foods and medications. A single urine pH reading is unimportant if the rest of the urinalysis is normal. Your veterinarian might want to look into it further if it consistently behaves abnormally.
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: An abnormal finding called bilirubinuria shows that the red blood cells in your pet's bloodstream are depleting more quickly than usual. It has been discovered in animals with autoimmune and liver diseases. It's important to keep in mind that pets with blood in their urine from a bladder infection may mistakenly stain the bilirubin pad on the dipstick, raising the possibility of a more severe liver condition.
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.
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: Crystals come in a wide variety of sizes, shapes, and colors. Unique crystals can help with the diagnosis of a particular condition. The crystals offer information that can affect how a disease is treated in more prevalent conditions like bladder infections. Your veterinarian may want to examine a fresh sample of urine right away because crystals can develop in urine after it has been collected.
Bacteria: It is possible that there is a bacterial infection somewhere in the urinary system given the presence of bacteria and inflammatory cells in the sediment. In order to identify the types of bacteria present and the appropriate antibiotic to treat the infection, the urine should ideally be sent to a laboratory for culture and sensitivity testing.
Tissue Cells: Increased cellularity has been connected to a number of diseases, including cancer, prostate problems, bladder stones, inflammation of the urinary tract, and stones in the bladder. Samples taken during catheterization frequently have more tissue cells than usual. Your veterinarian might suggest having the sediment cytologically prepared if the cells seem abnormal. This makes it possible to look at the tissue cells in greater detail.