Why Does My Pet Need a Urinalysis?

Our vets in Douglasville strongly believe in educating our clients so they can be the best possible pet owners. Today, we'll discuss urinalysis for dogs and cats, along with how to understand your pet's urinalysis results so you can make the best decisions regarding their medical care. 

What is a Urinalysis?

This simple diagnostic test determines the physical and chemical properties of urine. Typically used to assess the health of an animal's kidneys and urinary system, a urinalysis can also help your vet identify issues in other organ systems. 

All cats and dogs eight years of age and older should have an annual urinalysis. Your veterinarian may also recommend a urinalysis if your pet has blood in their urine, increased frequency of urination or increased water intake. 

How is Urine Collected?

There are three main methods of collecting urine from cats and dogs:

Catheterization: This method is an excellent choice if a voluntary sample is unavailable, particularly in male dogs. It is also a less invasive method of collecting urine than cystocentesis. The vet will insert a very narrow sterile catheter into the bladder through the lower urinary passage (called the urethra). 

Mid-Stream Free Flow: When your pet urinates voluntarily, a sample is collected in a sterile container during urination. This type of sample is known as a "free flow" or "free catch" sample. Benefits of this method include the fact that is is completely non-invasive and can be collected at home by the pet owner. 

Cystocentesis: A sterile needle and syringe are used to collect urine from the bladder. This type of sample is ideal for evaluating the bladder and kidneys, along with detecting bacterial infection. The benefit of cystocentesis is that debris from the lower urinary tract will not contaminate the urine. That said, this procedure is slightly more invasive than others and is only useful if your pet has a full bladder. 

Understanding the Results of a Urinalysis 

Here are the four main steps your vet will take to conduct a urinalysis:

1. Assess appearance: Color and turbidity (cloudiness).
2. Measure the concentration (density) of the urine.
3. Measure pH (acidity) and assess the urine's chemical composition. 
4. Examine the solid material (urine sediment) and cells contained in the urine using a microscope. 

Because crystals, bacteria nd cells can alter the composition (dissolve or multiply) of urine, samples should be read within 30 minutes of being collected. If you collect a urine at home, please return it as soon possible to our veterinary hospital. 

Unless we are assessing your pet's ability to concentrate urine or testing for Cushing's disease, we recommend taking the urine sample first thing in the morning. 

Color & Turbidity

Healthy urine typically ranges from pale yellow to light amber in color, and is clear or only slightly cloudy. Dark yellow urine usually points to your pet being dehydrated or needing to drink more water. 

Urine that's not yellow (for example, brown, red, orange or black) may contain substances that are not normally found in health urine. This can also indicate an underlying health condition. 

Increased turbidity or cloudiness in urine indicates the presence of solid materials or cells. When there are inflammatory cells, crystals, debris, mucus or blood present, turbidity will increase. The sediment will be examined to determine what is present and its significance. 

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.

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 caused 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:

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.

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: There are numerous types of crystals that 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.