Urinalysis: What It Tests For, Normal Results, When to Worry

What the urinalysis test shows

A urinalysis reads one urine sample three ways at once: a physical look at color, clarity and concentration; a chemical dipstick — a reagent strip that reacts to protein, glucose, ketones, blood, leukocyte esterase, nitrite, bilirubin and urobilinogen and reads pH and specific gravity; and a microscopic exam of the spun sediment for blood cells, casts, crystals, bacteria and epithelial cells. MedlinePlus calls it one test for many substances that should not normally be in urine.

That breadth makes it a first-pass screen, not a precise measure of any one thing — unlike the targeted urine tests that follow it up. Microalbuminuria and 24-hour urine protein quantify protein loss, a urine culture identifies the bacteria behind an infection, and urine osmolality measures concentrating ability more exactly than specific gravity. The dipstick flags a problem; these tests confirm and size it.

Urinalysis normal range

Most lines are reported qualitatively (negative/positive) or semi-quantitatively (trace, 1+ to 4+, or cells per high-power field, HPF), so there is no SI conversion; the numeric exceptions — pH and specific gravity — are dimensionless and read the same worldwide. Typical adult values:

These points, consistent with StatPearls, depend on the lab, collection method and hydration — read a result against your own report.

What abnormal urinalysis findings mean

With a dozen results on one report, “abnormal” depends on which line is flagged — the common, important positives, roughly by how often they change care:

• Blood (hematuria). The AUA defines microscopic hematuria as three or more red cells per HPF on microscopy — a positive dipstick alone must be confirmed. Causes run from infection, stones and exercise to, less often, bladder or kidney tumors; visible blood needs prompt urology review.
• Leukocyte esterase and nitrite. Together these point to a urinary tract infection — nitrite is specific but easily missed, esterase more sensitive. A urine culture confirms the organism before antibiotics.
• Protein (proteinuria). A key flag for kidney disease. As the dipstick is only a rough guide, KDIGO advises confirming it with a quantitative albumin-to-creatinine ratio (microalbuminuria).
• Glucose (glucosuria). Sugar spills into urine once blood glucose passes the kidney’s threshold (about 180 mg/dL), prompting a check of blood glucose and HbA1c for diabetes.
• Ketones. Seen with fasting, low-carb diets, illness or pregnancy — but glucose plus ketones with symptoms can signal diabetic ketoacidosis and needs same-day care.
• Bilirubin or urobilinogen. Point to a liver or bile-duct problem or red-cell breakdown, and pair with ALT and AST.
• Casts and crystals. Red-cell casts suggest inflammation inside the kidney (glomerulonephritis), white-cell casts a kidney infection, and crystals can accompany stones.

When a urinalysis can mislead

A dipstick is easy to over-read, so results are weighed against the sample and the person:

• Contamination. Squamous epithelial cells or menstrual blood can mimic infection or hematuria; a repeat clean-catch or catheter sample settles it.
• Concentration and interference. A dilute sample can hide real protein or bacteria and a concentrated one exaggerates them; high-dose vitamin C can falsely lower the blood and glucose pads.
• Transient protein. Fever, hard exercise and long periods upright (orthostatic proteinuria in teenagers) raise urine protein briefly, so an isolated result is rechecked on a first-morning sample.
• What a normal screen misses. A clean dipstick does not rule out early diabetic kidney disease (that needs an albumin-to-creatinine ratio) or bladder cancer with visible blood, and it misses proteins such as myeloma light chains.
• Findings that need no treatment. Bacteria without symptoms (asymptomatic bacteriuria) are common and, per the USPSTF, are neither screened nor treated in non-pregnant adults — pregnancy is the main exception.

What to test alongside

Urinalysis is a starting point; the follow-ups depend on which line was abnormal:

• Microalbuminuria (urine ACR) — quantifies protein, the earliest sign of kidney damage.
• 24-hour urine protein — a fuller measure of heavier loss.
• Urine culture — identifies the bacteria and its drug sensitivity.
• Urine osmolality — a precise read of concentrating ability.
• Creatinine clearance and blood creatinine — overall kidney function.
• Glucose and HbA1c — when sugar shows in the urine.
• ALT and AST — when bilirubin or urobilinogen is raised.

What to do about an abnormal result

1. Don’t self-treat. A single abnormal dipstick rarely means disease, and leftover antibiotics or supplements can mask the real problem.
2. Repeat before you react. Contamination and dehydration are common, so a finding is often rechecked on a fresh clean-catch or first-morning sample.
3. Match the follow-up to the finding. Protein → albumin-to-creatinine ratio and kidney function; blood → microscopy, then urology if confirmed; leukocytes with symptoms → a urine culture; glucose → blood glucose and HbA1c.
4. Act on red flags fast — visible blood, fever with flank pain, or heavy protein with swelling should be seen without delay.
5. Start with your primary-care doctor, who reads the strip against your symptoms and orders the next test, referring to a nephrologist or urologist only if needed.

Mini-FAQ

What does a urinalysis test for?

A urinalysis screens one urine sample three ways — a visual check, a chemical dipstick and a microscope exam — for blood, protein, glucose, ketones, signs of infection and other substances not normally in urine.

Does a positive urine dipstick mean I have a UTI?

Not on its own. A positive leukocyte esterase or nitrite raises suspicion, but a urine culture confirms infection and identifies the bacteria before antibiotics. Adults with no symptoms who are not pregnant are generally neither screened nor treated.

Should I worry about a trace of protein or blood?

Usually not from a single test. Fever, exercise, dehydration, contamination and menstruation all cause brief, harmless traces, so an isolated finding is usually repeated before it means anything. A persistent or heavy result warrants a full work-up.

Can a normal urinalysis rule out kidney disease?

Not completely. A standard dipstick can miss early kidney damage, which is why people with diabetes or high blood pressure also have a urine albumin-to-creatinine ratio (ACR) and blood creatinine (eGFR) checked.