Many conditions and diseases that our pets may have can be diagnosed with a urinalysis test. Here, our Zeeland vets describe the process of annual urinalysis testing, what your vet is looking for, and why your cat or dog should have an annual urinalysis done.
What is a Urinalysis?
This simple diagnostic test determines the chemical and physical properties of urine. Primarily used to evaluate the health of the kidneys and urinary system, a urinalysis can also reveal issues with other organ systems.
All pets eight years of age and older should have an annual urinalysis. Your veterinarian may also recommend this test if your pet has been drinking more water, urinating more or if blood is visible in the urine.
How is Urine Collected?
There are three methods of collecting urine from cats and dogs:
Cystocentesis: A syringe and sterile needle are used to collect urine from the bladder. The benefit of this method is that the urine is not contaminated by debris from the lower urinary tract. This sample is ideal for detecting bacterial infection as well as evaluating the kidneys and bladder. This procedure is slightly more invasive than other methods and is only useful if your pet has a full bladder.
Catheterization: A less invasive method of extracting urine from the bladder in pets, this method is an excellent option when a voluntary sample is unavailable, particularly in male dogs. A very narrow sterile catheter is inserted into the bladder through the urethra (lower urinary passage).
Mid-Stream Free Flow: This type of sample is collected in a sterile container when a pet urinates voluntarily. Often referred to as "free flow" or a "free catch" sample, this method is completely non-invasive and the pet owner can collect the urine sample at home.
Understanding the Results of a Urinalysis for Dogs & Cats
A urinalysis has four main components:
- Assess appearance: color and turbidity (cloudiness)
- Measure concentration (also referred to as density) of the urine
- Measure pH (acidity) and analyze the urine's chemical composition
- Examine the urine's cells and solid material (sediment) in the urine using a microscope
Urine samples should be read within 30 minutes of being collected, since other factors (such as bacteria, cells and crystals) can change the composition (dissolve or multiply).
If you collect a urine sample at home, please bring it to your veterinary clinic as soon as possible. Unless we are evaluating your pet's ability to concentrate urine or screening for Cushing's disease, the actual timing of urine collection is insignificant. However, if we are screening for Cushing's disease or evaluating ability to concentrate urine, a urine sample should be taken first thing in the morning.
Color & Turbidity
Urine typically ranges from pale yellow to light amber in color and is clear to slightly cloudy. If your pet's urine is dark yellow, this usually indicates they are dehydrated or need to drink more water.
Orange, red, brown or black urine may contain substances not normally found in healthy urine and may point to an underlying health condition.
Increased turbidity or cloudiness in urine indicates the presence of cells or other solid materials. If there are crystals, mucus, debris, inflammatory cells or blood present, turbidity will increased. The sediment will be examined to to identify what is present 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 and cats may indicate underlying disease.
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 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 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 the urine can include:
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.
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.
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.