A urinalysis test can help detect several conditions and diseases that your cat or dog may have. Today, our Clackamas vets discuss the importance of regular urinalysis testing for pets.
Urinalysis for Pets
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 senior 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.
Collecting a Urine Sample
There are three primary methods for collecting urine from cats and dogs:
Cystocentesis: This involves using a sterile needle and syringe to collect urine directly from the bladder. The advantage of cystocentesis is that the urine is not contaminated by debris from the lower urinary tract. It is an ideal method for evaluating the bladder and kidneys and detecting bacterial infections. However, it is a slightly more invasive procedure and requires a full bladder for effectiveness.
Catheterization: Catheterization is a less invasive technique for retrieving urine from the bladder, particularly in male dogs. It involves inserting a narrow sterile catheter into the bladder through the urethra, which is the lower urinary passage.
Mid-stream Free Flow: This method involves allowing the pet to urinate voluntarily, while collecting a sample into a sterile container. It is often referred to as a "free flow" or "free catch" sample. The benefits of this method include its non-invasive nature and the convenience of collecting the sample at home by the pet owner.
Each method has its advantages and suitability depending on the specific circumstances and requirements for urine collection.
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.
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 are evaluating your pet's ability to concentrate urine, or screening for Cushing's disease, the actual timing of urine collection is usually insignificant. But if we are screening for Cushing's disease or evaluating your pet's ability to concentrate urine, we want a urine sample taken first thing in the morning.
Color & Turbidity
Urine that ranges 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 (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.
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
Urine concentration refers to the density of the urine and can be an indicator of kidney health. Normally, a healthy kidney produces concentrated urine, while watery or dilute urine in dogs and cats might suggest an underlying medical condition.
When there is an excess of water in the body, the kidneys allow it to be eliminated through the urine, resulting in more diluted urine. Conversely, when there is a shortage of water, the kidneys reduce the amount of water lost in the urine, leading to more concentrated urine.
Occasional episodes of dilute urine in a dog or cat may not be a cause for concern. However, if a pet consistently passes dilute urine, it could indicate an underlying kidney or metabolic disease that should be further investigated.
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 your pet's 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.