Why would your veterinarian recommend a urinalysis?
A urinalysis is a simple diagnostic test that determines urine's physical and chemical properties. 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.
How to collect a pet's urine?
There are three main ways to collect urine from cats and dogs:
Cystocentesis: To collect a urine sample that is not contaminated by debris from the lower urinary tract, a sterile needle and syringe are used to extract urine from the bladder. This method, known as cystocentesis, is particularly useful for evaluating the bladder and kidneys and detecting bacterial infection. It should be noted that this procedure is more invasive than other methods and can only be performed when the pet's bladder is full.
Catheterization: Catheterization is a minimally invasive technique for extracting urine from a dog's bladder. This method is especially useful when a voluntary urine sample cannot be obtained, particularly in male dogs. A sterile, narrow catheter is inserted through the urethra, the lower urinary passage, into the bladder to collect the urine.
Mid-stream Free Flow: When collecting a urine sample from a pet, a "free flow" or "free catch" sample can be taken. This method involves the pet urinating voluntarily into a sterile container. It is a completely non-invasive method and can be done by the pet owner at home.
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 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 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
The color of urine can vary from pale yellow to light amber. It should normally be clear to slightly cloudy. If the urine appears dark yellow, it could indicate that your pet needs to drink more water or is dehydrated. However, if the urine has an unusual color like orange, red, brown, or black, it may contain substances that are not usually found in healthy urine. This could indicate that there is an underlying health issue that needs to be addressed.
An increase in turbidity or cloudiness in the urine signals the presence of cells or other solid materials. Turbidity can increase if there is blood, inflammatory cells, crystals, mucus, or debris in the urine. The sediment in the urine will be examined to determine what is present and whether it is significant.
Concentration
The concentration of urine refers to its density. When a kidney functions normally, it produces dense or concentrated urine. On the other hand, if a pet's urine is watery or dilute, it may indicate an underlying disease.
If the body has excess water, the kidneys allow it to pass out in the urine, making the urine more watery or dilute. If the body is water-deficient, the kidneys reduce the amount of water lost in the urine, making it more concentrated.
If a pet passes dilute urine occasionally, it may not be a cause for concern. However, if a pet continuously passes dilute urine, it may indicate an underlying kidney or metabolic disease that requires further medical 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 your pet's urine can include:
Red Blood Cells: Red blood cells may indicate bladder wall or kidney trauma or irritation. The technician will find red blood cells in pets' urine with bladder or kidney infections, bladder stones, or interstitial cystitis. 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 indicating that red blood cells in your pet's bloodstream are being destroyed faster than normal. 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 unique and can aid in diagnosing 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 being collected, your veterinarian may want to examine a fresh sample immediately.
Bacteria: The presence of bacteria and 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 people or pets. If you are concerned about your pet's health, contact your veterinarian right away for diagnosis and treatment.