Urinalysis is the analysis of a urine sample, typically combining dipstick chemical testing with microscopic examination of urine sediment. Urinalysis is one of the most commonly ordered tests in medicine, used for screening, evaluating urinary symptoms, monitoring kidney disease, and as part of routine medical care. The test is simple and inexpensive but provides substantial information about kidney function, urinary tract infection, and metabolic conditions. This guide covers what urinalysis tests, normal results, and what abnormal findings may indicate.
What urinalysis includes
Standard urinalysis has three components:
Visual inspection: Color, clarity, odor.
Dipstick chemical analysis: Tests for pH, specific gravity, glucose, ketones, blood, leukocyte esterase, nitrites, protein, urobilinogen, and bilirubin.
Microscopic examination: Cells (RBCs, WBCs, epithelial cells), casts, crystals, bacteria, and other elements in urine sediment.
Common dipstick findings
Glucose: Normally absent. Presence suggests diabetes (when blood glucose exceeds renal threshold ~180 mg/dL) or rare renal glucosuria.
Ketones: Normally absent or trace. Presence suggests diabetic ketoacidosis, fasting/starvation, ketogenic diet, or alcoholic ketoacidosis.
Protein: Normally minimal. Persistent protein suggests kidney damage. Quantification with urine albumin/creatinine ratio is more precise than dipstick.
Blood: Hematuria can indicate UTI, kidney stones, kidney disease, urinary tract cancer, or recent menstruation. Microscopic and dipstick blood results sometimes differ.
Leukocyte esterase: Suggests white blood cells in urine, typically from UTI or other inflammation.
Nitrites: Suggests bacterial UTI (gram-negative bacteria convert nitrate to nitrite).
Bilirubin and urobilinogen: Abnormalities suggest liver disease or hemolysis.
Microscopic findings
Red blood cells (RBCs): Confirms hematuria; specific patterns (dysmorphic RBCs) suggest glomerular origin vs lower urinary tract source.
White blood cells (WBCs): Indicates inflammation, typically UTI but other causes possible.
Bacteria: Confirms infection when combined with WBCs.
Casts: Cylindrical structures formed in renal tubules. Different cast types suggest different kidney conditions — RBC casts (glomerulonephritis), WBC casts (pyelonephritis), waxy casts (advanced kidney disease).
Crystals: Some are normal (uric acid, calcium oxalate); others suggest specific conditions (cystine, struvite).
Epithelial cells: Normal in small numbers; large numbers may suggest contamination or specific conditions.
Common reasons for ordering urinalysis
- Suspected UTI
- Workup for hematuria
- Screening for diabetes
- Kidney disease evaluation
- Pregnancy testing
- Pre-surgical evaluation
- Workup for unexplained symptoms
Hematuria workup
Microscopic hematuria (asymptomatic blood on urinalysis) requires evaluation:
- Repeat urinalysis to confirm
- Workup for UTI if symptoms present
- Imaging (CT urogram or renal ultrasound) for structural evaluation
- Cystoscopy for high-risk patients (older, smokers, occupational exposures)
The American Urological Association and AAU guidelines specify when more aggressive workup is indicated.
UTI diagnosis
The combination of leukocyte esterase positive, nitrites positive (or significant), and bacteria on microscopy strongly supports UTI in symptomatic patients. Empirical antibiotic therapy is often started while awaiting culture confirmation. Asymptomatic patients with positive urinalysis findings may not need treatment, particularly the elderly.
Frequently Asked Questions
How do I collect a urine sample for urinalysis?
Standard “clean catch” midstream collection is most common. Genital area is cleaned, the first part of urination is discarded, and the middle stream is collected in the sterile container.
Do I need to fast for urinalysis?
No. Fasting isn’t required.
What does protein in urine mean?
Persistent proteinuria suggests kidney damage. Diabetic kidney disease, glomerulonephritis, and other kidney diseases cause proteinuria. Trace protein can be normal in some situations.
What about glucose in urine?
Suggests blood glucose has exceeded the renal threshold (~180 mg/dL). Most commonly indicates undiagnosed or poorly controlled diabetes.
Can I have a UTI without symptoms?
Yes, asymptomatic bacteriuria is common in elderly women. Treatment is generally not recommended for asymptomatic cases except in pregnancy or before urological procedures.
The bottom line on urinalysis
Urinalysis provides broad screening for kidney disease, urinary infection, diabetes, and many other conditions through a simple, inexpensive test. Dipstick and microscopic findings together provide more information than either alone. Abnormal results often warrant follow-up testing to confirm and characterize findings. Discuss results with your healthcare provider in clinical context.