A urine test can detect a surprisingly wide range of health information, from infections and kidney disease to pregnancy, diabetes, liver problems, and drug use. The specific findings depend on the type of test ordered. A standard urinalysis checks your urine’s physical and chemical properties using a dipstick and sometimes a microscope, while specialized tests look for hormones, drugs, or cancer markers.
What a Standard Urinalysis Measures
A routine urinalysis is one of the most commonly ordered lab tests. It evaluates your urine in three ways: a visual check of color and clarity, a chemical dipstick analysis, and sometimes a microscopic examination. The dipstick alone tests for about ten different markers in under two minutes.
The chemical analysis checks for glucose (sugar), protein, blood, ketones, bilirubin, urobilinogen, nitrites, leukocyte esterase (a sign of white blood cells), and pH. It also measures specific gravity, which reflects how concentrated your urine is. The normal range for specific gravity in adults is 1.005 to 1.030, with most samples falling between 1.01 and 1.025. A very dilute sample can suggest overhydration or reduced kidney function, while a very concentrated one may indicate dehydration.
Signs of Urinary Tract Infections
Two dipstick markers are particularly useful for spotting bacterial infections. Leukocyte esterase indicates that white blood cells are present, which means your immune system is fighting something in the urinary tract. Nitrites appear when certain bacteria convert naturally occurring nitrates in your urine into nitrites. If both markers are positive, a UTI is very likely.
A negative nitrite result doesn’t rule out infection, though. Some bacteria don’t produce nitrites, so your provider will weigh both markers together and may order a urine culture to confirm which organism is involved and what will treat it.
Kidney Health and Protein in Urine
Healthy kidneys filter waste while keeping useful molecules like protein in your blood. When the kidneys are damaged, protein (especially albumin) leaks into the urine. A standard dipstick can pick up moderate amounts of protein, but a more sensitive test called the urine albumin-to-creatinine ratio, or uACR, can catch much smaller leaks.
A normal uACR is less than 30 mg/g. Anything above that threshold may indicate kidney disease, even if other kidney function numbers still look normal. This test is routinely recommended for people with diabetes or high blood pressure, since both conditions damage the kidneys gradually and early detection changes treatment decisions.
Glucose, Ketones, and Diabetes
Glucose doesn’t normally appear in urine. When it does, it typically means blood sugar levels have been high enough that the kidneys can’t reabsorb all the sugar being filtered. This is one of the classic early signs of undiagnosed or poorly controlled diabetes.
Ketones show up when your body burns fat for energy instead of glucose. This can happen during fasting, very low-carb diets, or prolonged vomiting. In someone with diabetes, ketones in urine can signal a dangerous condition called diabetic ketoacidosis, where acid builds up in the blood.
Liver and Blood Disorders
Two markers on the dipstick reflect how well your liver is functioning: bilirubin and urobilinogen. Your body produces bilirubin when it breaks down old red blood cells. The liver processes bilirubin into bile, which travels to the intestines to help with digestion. Bacteria in the gut then convert some of that bilirubin into urobilinogen, a portion of which re-enters the bloodstream and gets filtered into urine.
High urobilinogen levels can signal that the liver is struggling to recycle it back into bile, as happens with hepatitis or cirrhosis. It can also mean the body is breaking down red blood cells faster than normal, a condition called hemolytic anemia. Very low or absent urobilinogen suggests something is blocking bile flow, which may point to gallbladder or bile duct problems. Bilirubin itself should not appear in urine at all. When it does, it often indicates liver disease or a blockage in the bile ducts.
What Microscopic Examination Reveals
If the dipstick flags anything unusual, the lab may examine a sample under a microscope. This step identifies cells, crystals, and casts that provide more specific diagnostic clues.
Red blood cells in urine (hematuria) can point to anything from a kidney stone to a bladder infection to glomerular disease. When red blood cells are bundled into tube-shaped structures called casts, it typically indicates a problem originating in the kidneys rather than the bladder or urethra. White blood cell casts similarly suggest kidney inflammation rather than a lower urinary tract infection.
Crystals are common and often harmless. Calcium oxalate and triple phosphate crystals appear in many healthy people. Rarer crystal types, like cystine or tyrosine, can indicate inherited metabolic conditions or severe liver disease. Urine pH helps distinguish between types of kidney stones: uric acid and cystine stones form in acidic urine, while calcium-based and staghorn stones are associated with alkaline urine.
Pregnancy and Hormone Detection
Home pregnancy tests and clinical urine pregnancy tests both detect human chorionic gonadotropin (hCG), a hormone produced after a fertilized egg implants in the uterus. Clinical urine tests typically have a sensitivity threshold of 25 IU/L, meaning they can detect hCG at that concentration or higher. Most home tests have similar sensitivity, though this varies by brand.
hCG rises rapidly in early pregnancy, roughly doubling every two to three days. This is why testing too early can produce a false negative. Waiting until the first day of a missed period gives the hormone enough time to reach detectable levels in most cases.
Drug Screening and Detection Windows
Urine drug tests are widely used for employment screening, legal proceedings, and medical monitoring. A standard panel screens for five drug classes: amphetamines, cocaine, opioids, THC (marijuana), and phencyclidine (PCP). Extended panels may add benzodiazepines, barbiturates, and other substances.
How long a substance remains detectable depends on the drug, frequency of use, metabolism, and hydration. General detection windows include:
- THC: 1 to 3 days for infrequent users, up to 13 days for frequent users, and as long as 45 days in heavy, chronic use
- Cocaine: 1 to 2 days
- Amphetamines: 1 to 7 days depending on the specific substance
- Opioids: 1 to 3 days for most (codeine, oxycodone, morphine), though methadone can be detected for up to 14 days and fentanyl up to 7 days
- MDMA (ecstasy): 1 to 3 days
Common Causes of False Positives
Several everyday medications can trigger a positive result on an initial screening test. Pseudoephedrine and certain nasal decongestant inhalers containing levomethamphetamine can cause a false positive for amphetamines. The antidepressant bupropion and the antihistamine promethazine can do the same. Dextromethorphan, a cough suppressant found in many over-the-counter cold medicines, can trigger false positives for both opioids and PCP.
Proton pump inhibitors (used for acid reflux) and some anti-inflammatory drugs have been known to produce false positives for THC. Even hemp-containing foods can occasionally trigger a cannabinoid result. If you test positive on an initial screen, a confirmation test using a more precise method is standard practice and will distinguish a true positive from an interference.
Specialized Urine Biomarkers
Beyond routine testing, urine can be analyzed for highly specific biomarkers. One notable example is bladder cancer monitoring. Several FDA-cleared urine tests can detect proteins or genetic markers shed by bladder tumors. These include tests that measure nuclear matrix protein 22 (NMP22), a protein released by tumor cells, and others that analyze gene expression patterns in urine samples. These tests are used alongside cystoscopy for surveillance in people with a history of bladder cancer, not as standalone screening tools for the general population.
Urine tests are also used to measure cortisol levels over a 24-hour period (helpful for diagnosing adrenal disorders), to screen for inherited metabolic diseases in newborns, and to monitor protein loss in conditions like nephrotic syndrome. The range of what urine can reveal continues to expand, making it one of the most versatile and least invasive diagnostic tools available.