A urine test (urinalysis) is one of the oldest and most versatile diagnostic tools in medicine. A small sample can reveal information about your kidneys, urinary tract, metabolic health and hydration status — often within minutes. The report lists a dozen or more parameters, and understanding each one helps you make sense of what your doctor is looking for.
Physical and chemical properties
- Colour — pale yellow is normal; dark amber suggests dehydration; red or brown may indicate blood or muscle breakdown
- Clarity — cloudy urine can indicate infection or high protein content
- pH — normal is 4.5–8.0; extremes can reflect diet, kidney disease or infection
- Specific gravity — measures concentration; low values suggest dilute urine (over-hydration or diabetes insipidus); high values suggest dehydration or kidney concentration issues
Biochemical markers
- Glucose — should be absent; presence suggests diabetes or a low renal threshold
- Protein — small amounts can follow exercise or fever; persistent protein (proteinuria) may indicate kidney damage
- Ketones — detected in fasting, low-carb diets or uncontrolled type 1 diabetes
- Nitrites — a marker for bacterial infection; produced by many urinary pathogens
- Leukocyte esterase — indicates white blood cells in the urine, suggesting infection or inflammation
- Blood (haematuria) — microscopic blood has many causes from strenuous exercise to kidney stones; should always be evaluated
- Bilirubin and urobilinogen — elevated in liver disease or haemolysis
Microscopy findings
When a urinalysis is abnormal, the lab may also perform microscopic examination of the centrifuged sample. This can reveal red blood cell casts (which point to glomerulonephritis), white blood cell casts (kidney infection), bacteria and crystals. Crystal types — uric acid, calcium oxalate, struvite — help identify the composition of kidney stones if you have them.
Most single abnormal urinalysis results need context. A positive nitrite test in a person with no symptoms may not need treatment. Persistent protein across multiple tests almost always does. The pattern over time matters far more than a single reading.