In the post, our Tracy vets will discuss urinalysis for dogs, as well as how to understand your pet's urinalysis results so you can make the best decisions regarding their health care.
What is a Urinalysis?
A urinalysis is a diagnostic test that determines the physical and chemical properties of urine. It is 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 dog 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:
Mid-stream Free Flow
The pet urinates voluntarily, and a sample is collected into a sterile container as the pet urinates. This type of sample is frequently referred to as a "free flow" or "free catch" sample. The benefits of this method include the fact that it is completely non-invasive and that the pet owner can collect the urine sample at home.
Urine is collected from the bladder using a sterile needle and syringe. The benefit of cystocentesis is that the urine is not contaminated by debris from the lower urinary tract. This sample is ideal for evaluating the bladder and kidneys as well as detecting bacterial infection.
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. A very narrow sterile catheter is inserted into the bladder through the lower urinary passage (called the urethra).
Understanding the Results of a Urinalysis
There are four main parts to a urinalysis
- Assess appearance: color and turbidity (cloudiness).
- Measure the concentration of the urine.
- Measure pH (acidity) and analyze the chemical composition of the urine.
- Examine the cells and solid material present in the urine using a microscope.
Urine samples should be read within 30 minutes of the collection. If you collect a urine sample at home, please return it as soon as possible to your veterinary clinic. If your dog is being 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
Urine should range 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 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 sample will be examined to determine the composition and whether it is significant.
Consider concentration to be the density of the urine. A healthy kidney produces dense (concentrated) urine, whereas watery (dilute) urine in dogs may indicate underlying health problems.
If there is an excess of water in the body, the kidneys allow it to pass out in the urine, making the urine more watery or dilute. If water is deficient, the kidneys reduce the amount of water lost in the urine, making it more concentrated.
If a dog 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.
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.
Cells & Solid Material (Urine Sediment)
Some of the cells present in the urine can include:
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.
Urine should not contain any sugar. The presence of sugar in the urine may signal the presence of diabetes mellitus.
Ketones are abnormal byproducts that your pet's cells produce when they lack an adequate energy source. If your pet tests positive for ketones in its urine, a Diabetes Mellitus workup will be performed.
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 is often found in pets suffering from liver disease and autoimmune diseases.
Urobilinogen in urine indicates that the bile duct is open and bile can flow from the gallbladder into the intestine.
Blood in a dog's urine can indicate an infection, an inflammatory problem, or stones in the bladder or kidney.
Red blood cells may indicate bladder wall or kidney trauma or irritation. It may also be an early sign of cancer of the urinary tract.
White blood cells could indicate an infection or an inflammatory process in the bladder or kidney.
There are numerous types of crystals that vary in size, shape, and color which can aid in the diagnosis of a specific condition.
The presence of bacteria as well as inflammatory cells in the sediment suggests that there is a bacterial infection somewhere in the urinary system.
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 more in-depth examination.
Note: The advice provided in this post is intended for informational purposes and does not constitute medical advice regarding pets. For an accurate diagnosis of your pet's condition, please make an appointment with your vet.