A dog urinalysis tests for signs of urinary tract infections, kidney disease, diabetes, liver problems, bladder stones, and dehydration. It’s one of the most common veterinary diagnostics because a single urine sample reveals information about multiple organ systems at once. The test has four main parts: a visual inspection, a concentration measurement, a chemical dipstick analysis, and a microscopic examination of sediment.
Urine Concentration and Hydration
One of the first things your vet measures is urine specific gravity, which tells how concentrated your dog’s urine is. This is a direct reflection of how well the kidneys are doing their job of filtering and concentrating waste. A healthy, well-hydrated dog with normal kidney function typically produces urine with a specific gravity of 1.030 or higher when the body needs to conserve water. Values consistently below that range can signal kidney disease, hormonal disorders like Cushing’s disease, or simply that your dog is drinking excessive amounts of water.
The color of urine loosely tracks with concentration. In a study comparing urine color to specific gravity, 80% of samples with the darkest color score had a specific gravity at or above 1.030, while the palest samples were almost always dilute. But color alone isn’t reliable enough for diagnosis, which is why the refractometer reading matters.
The Chemical Dipstick Panel
A small paper strip dipped into the urine sample reacts to several chemical markers at once. Each one points to a different area of your dog’s health.
pH measures how acidic or alkaline the urine is. The normal range for dogs falls between 5.0 and 8.0, and diet is the biggest everyday influence. pH matters because it affects the types of crystals and stones that can form. Dogs fed diets designed to acidify urine may be nearly three times as likely to develop calcium oxalate stones compared to dogs on neutral or alkaline diets, though this relationship is complex and varies by breed. Miniature Schnauzers, for example, tend to have higher urine pH than Labrador Retrievers.
Glucose should not be present in normal dog urine. It appears when blood sugar exceeds the kidneys’ ability to reabsorb it, which happens at blood glucose levels between 160 and 220 mg/dL in most dogs. The most common cause is diabetes mellitus, though kidney dysfunction can also let glucose slip through at lower blood sugar levels.
Ketones show up when the body shifts from burning carbohydrates to burning fat for energy. In dogs, this is most often linked to uncontrolled diabetes, though prolonged fasting or starvation can also produce ketones. Finding both glucose and ketones together in a urine sample is a red flag for diabetic ketoacidosis, a serious complication.
Bilirubin is a byproduct of red blood cell breakdown, processed by the liver. Dogs are unique among domestic animals in that small amounts of bilirubin can appear in concentrated urine and still be normal. Elevated levels, however, suggest liver disease, bile duct obstruction, or excessive red blood cell destruction.
Blood on the dipstick can mean intact red blood cells in the urine, free hemoglobin from destroyed red blood cells, or myoglobin from damaged muscle tissue. Causes range from bladder infections and stones to clotting disorders, trauma, and cancer. The dipstick flags the presence of blood, but figuring out the source requires looking at the sediment under a microscope.
Protein in small amounts can be normal, but persistent or significant protein loss through urine often points to kidney damage. When protein shows up on the dipstick, your vet may order a urine protein-to-creatinine ratio to quantify exactly how much protein is leaking. In dogs, a ratio below 0.5 is normal, between 0.5 and 1.0 is borderline, and anything above 1.0 is abnormal and warrants further investigation.
What the Microscope Reveals
After the chemical tests, a small amount of urine is spun in a centrifuge and the sediment is examined under a microscope. This is where your vet looks for cells, crystals, bacteria, and casts that the dipstick can’t identify on its own.
White blood cells in elevated numbers indicate inflammation somewhere in the urinary tract, most often from a bacterial infection. Red blood cells in large numbers point to active bleeding, which could originate from the kidneys, ureters, bladder, or urethra. Small numbers of both cell types can be normal depending on how the sample was collected.
Bacteria visible under the microscope, especially alongside white blood cells, strongly suggest a urinary tract infection. Your vet may recommend a urine culture to identify the specific bacteria and determine which treatment will be most effective.
Tissue cells from the lining of the urinary tract sometimes appear in sediment. A few are normal, particularly if urine was collected using a catheter. Higher numbers can indicate inflammation, bladder stones, prostate issues in male dogs, or in some cases, cancer.
Crystals and Stone Risk
Crystals in urine sediment are one of the most actionable findings because they signal a risk for bladder or kidney stones. The two most common types in dogs are struvite and calcium oxalate, and they form under very different conditions.
Struvite crystals most often develop alongside urinary tract infections caused by specific bacteria (particularly Staphylococcus and Proteus species) that produce an enzyme making the urine more alkaline. Because the underlying infection drives stone formation, treating the infection can sometimes dissolve struvite stones without surgery. Less commonly, struvite stones form without infection due to changes in how the kidneys handle acid.
Calcium oxalate crystals tend to form in more acidic urine and are linked to conditions that increase calcium excretion, along with genetic and dietary factors. Unlike struvite stones, calcium oxalate stones cannot be dissolved with diet changes or medication once formed. Dogs with these stones are typically evaluated for underlying metabolic disorders such as high blood calcium or overactive parathyroid glands.
Less common crystal types include urate (associated with liver shunts or a genetic defect in certain breeds like Dalmatians), cystine (caused by an inherited defect in how the kidneys reabsorb amino acids), and silica. Identifying cystine crystals in a dog’s urine is particularly significant because it confirms the dog is at risk of forming cystine stones.
Urinary Casts and Kidney Health
Casts are tiny tube-shaped structures that form inside the kidney’s filtering tubes and get flushed into the urine. A few hyaline casts (the simplest type, made of protein) can be normal and may appear after dehydration or heavy exercise. Other types carry more clinical weight. Granular casts suggest various forms of kidney disease. White blood cell casts point to kidney infection or inflammation within the kidney itself, rather than lower in the urinary tract. Red blood cell casts indicate microscopic bleeding originating in the kidney. Waxy casts are associated with advanced or chronic kidney disease.
The type and number of casts help your vet distinguish between a problem in the bladder (like an infection) and a problem in the kidneys themselves, which is a critical distinction for treatment.
How Sample Collection Affects Results
The way urine is collected matters more than most pet owners realize, because it directly affects how the results are interpreted. There are three main methods.
A free-catch sample is urine caught midstream during normal urination. It’s the easiest method but the most prone to contamination. Bacteria, cells, and debris from the skin, genitals, and urethra can end up in the sample. Research comparing collection methods found that voided samples had significantly higher bacterial counts and greater microbial diversity than samples taken directly from the bladder, with several bacterial groups overrepresented in voided urine that weren’t truly from the urinary tract.
Cystocentesis involves inserting a needle directly through the abdominal wall into the bladder, usually guided by ultrasound. It sounds invasive, but it’s quick, generally well-tolerated, and produces the cleanest sample. This is the gold standard for urine culture because it bypasses all potential sources of contamination. Catheterization, where a tube is passed through the urethra into the bladder, falls between the two in terms of sterility and may cause small numbers of tissue cells and red blood cells to appear in the sample simply from the collection process.
Your vet chooses the collection method based on what they’re testing for. A free-catch sample works fine for routine screening, but if infection is suspected, cystocentesis gives the most reliable answer.