Urinalysis for Dogs
A urinalysis is a simple diagnostic test that assesses urine's physical and chemical properties. It is mainly used to evaluate the health of the kidneys and urinary system, but it can also detect issues with other organ systems. All senior pets aged eight years or older should undergo a yearly urinalysis. Moreover, a urinalysis may be recommended if your dog drinks more water, urates more frequently, or has visible blood in their urine.
How Samples Are Collected for Urinalysis
There are three main ways to collect urine from dogs when we are performing urinalysis:
Cystocentesis: A sterile needle and syringe collect urine from your dog's bladder. This method's advantage is that it ensures the urine sample remains unadulterated by debris from the lower urinary tract. This sample type is best suited for assessing the bladder and kidneys and detecting bacterial infections. However, this procedure is slightly more invasive than other methods and can only be performed when the dog's bladder is full.
Catheterization: Catheterization is a minimally invasive technique for extracting urine from dogs' bladders. It is particularly useful when a voluntary sample is unavailable, especially in male dogs. The process involves inserting a narrow, sterile catheter into the bladder through the urethra, the lower urinary passage.
Mid-stream Free Flow: To collect a urine sample from a pet, a sterile container is held in place while the pet urinates voluntarily. This sample type is often called a 'free flow' or 'free catch' sample. This non-invasive method allows pet owners to collect urine samples at home.
What We Learn From Urinalysis for Dogs
There are four main components to a urinalysis for dogs:
- 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) in the urine using a microscope.
Your vet will need to examine the urine sample within 30 minutes of collection. Various factors, such as crystals, bacteria, and cells, can alter the sample's composition. If you collect a urine sample at home, it should be done immediately before heading over to the clinic. The timing of urine collection is usually insignificant unless we are testing your dog's urine concentration or screening for Cushing's disease. Collecting the urine sample first thing in the morning is best for these specific cases.
Color & Turbidity of the Urine
The color of their urine can preliminarily indicate your dog's health status. Normally, urine should be pale yellow to light amber, clear to slightly cloudy. However, if their urine is dark yellow, they may need to drink more water or might be dehydrated. On the other hand, if the urine is not yellow but appears orange, red, brown, or black, it could mean that there are substances in the urine that are not typically found in healthy urine, which may hint at an underlying medical condition.
Increased turbidity or cloudiness in the urine indicates the presence of cells or other solid materials. Turbidity increases when blood, inflammatory cells, crystals, mucus, or debris are present. Your vet will examine the urine sediment to better understand what is happening to your dog internally.
Concentration of Urine
When we talk about urine concentration, we refer to its density. A healthy kidney produces dense or concentrated urine. On the other hand, watery or dilute urine in dogs may indicate an underlying disease.
When excess water is in the body, the kidneys allow it to pass out in the urine, making it more watery or dilute. Conversely, when water is deficient, the kidneys reduce the water lost in the urine, resulting in more concentrated urine.
If a dog occasionally passes dilute urine, it may not necessarily be a cause for concern. However, if they consistently pass dilute urine, it could indicate an underlying kidney or metabolic disease. Therefore, it's best to consult a veterinarian for further investigation.
pH & Chemical Composition of the Urine
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.
What we Learn from Cells & Solid Material (Urine Sediment)
When conducting a urinalysis, it is important to examine the urine sediment. Urine sediment is the material that settles at the bottom of a centrifuged urine sample. The most common things in urine sediment are red blood cells, white blood cells, and crystals. Free-catch urine samples often contain small amounts of mucus and other debris.
Some of the cells present in your dog's urine can include:
Red Blood Cells: Your veterinarian may find red blood cells in dogs' 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: Your vet should not note protein when performing a dipstick test. A positive protein in urine test may indicate a bacterial infection, kidney disease, or blood in the urine.
Sugar: Like protein, sugar is another material that should not be found when urine testing. The presence of sugar in the urine may signal the presence of diabetes mellitus.
Ketones: If your dog tests positive for ketones in its urine, a diabetes mellitus workup will be performed. Ketones are abnormal byproducts your dog's cells produce when they lack adequate energy.
Bilirubin: Bilirubinuria indicates that the red blood cells in your dog'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: The dipstick can detect red blood cells or other components, such as hemoglobin or myoglobin, in your dog's urine. Blood in a dog's urine can indicate an infection, an inflammatory problem, or stones in the bladder or kidney.
Crystals: Crystals can vary in shape and size. 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.
Tissue Cells: The presence of bacteria and inflammatory cells in the urine sediment indicates a possible bacterial infection in the urinary system. It is best to send the urine sample to a laboratory for culture and sensitivity testing to determine the specific type of bacteria present and the most effective antibiotic treatment.
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.