Why does my pet need a urinalysis?

At Everhart Animal Hospital, we believe strongly in educating our clients so they can be the best possible pet owners. In this article, our Corpus Christi vets will explain what a urinalysis is for dogs and cats. They will also review how to understand your pet's urinalysis results so you can be confident when reading them.

What is a pet Urinalysis?

A urinalysis is a diagnostic test that determines the physical and chemical properties of urine. Primarily employed to assess kidney and urinary system health, a urinalysis can also detect problems in other organ systems. All pets aged eight and above should undergo an annual urinalysis. A urinalysis may be recommended if your pet exhibits increased urination or blood in the urine.

How is Urine Collected?

There are three main ways to collect urine from cats and dogs:

Cystocentesis: Urine is collected from the bladder using a sterile needle and syringe. The advantage of cystocentesis is that it provides a urine sample uncontaminated by debris from the lower urinary tract. This type of sample is optimal for assessing the bladder and kidneys, as well as identifying bacterial infections. While the procedure is somewhat more invasive compared to others, it's beneficial only when the pet's bladder is adequately 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: The pet urinates voluntarily, and a sample is collected into a sterile container as the pet urinates. 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.

Understanding the Results of a Urinalysis

There are four main parts to a urinalysis:

Urine samples should be read within 30 minutes of the collection because other factors (such as crystals, bacteria, and cells) can alter the composition (dissolve or multiply). If you collect a urine sample at home, please return it as soon as possible to your veterinary clinic. Unless we're assessing your pet's urine concentration or screening for Cushing's disease, the specific timing of urine collection typically doesn't matter. However, if we are screening for Cushing's disease it's preferable to collect the urine sample first thing in the morning.

Urine Color & Turbidity

Urine that ranges from pale yellow to light amber 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.

Elevated turbidity or cloudiness in urine suggests the presence of cells or solid materials. This turbidity intensifies with the presence of blood, inflammatory cells, crystals, mucus, or debris. The sediment will be analyzed to identify its components and assess its significance.

Urine 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.

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.

Urine 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, 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 cause for concern. If it is consistently abnormal, your veterinarian may wish to investigate further.

Cells & Solid Material in Urine

Some of the cells present in the urine can include:

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.

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. 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.

Crystals: Numerous types of crystals vary in size, shape, and color. Some crystals 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.

Bacteria: The presence of bacteria as well as inflammatory cells in the sediment suggests 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.

Does your pet need a urinalysis? Contact our Corpus Christi vets today to book the procedure or if you need more help understanding the results.