Lab tests, explained in plain language

Got a blood or urine test result and aren’t sure what it means? Here’s what common tests measure, a general reference range, and what high or low results can suggest — summarized from MedlinePlus. A result is never a diagnosis; your clinician interprets it.

• Leukocytes in urine (white blood cells in urine)
• MCHC (mean corpuscular hemoglobin concentration)
• MCV (mean corpuscular volume)
• Hemoglobin A1C (HbA1c) test
• Complete blood count (CBC)
• C-reactive protein (CRP) test
• ESR (erythrocyte sedimentation rate / sed rate)
• Ferritin blood test
• TSH (thyroid-stimulating hormone) test
• Vitamin D blood test (25-hydroxyvitamin D)
• eGFR (estimated glomerular filtration rate)
• Creatinine blood test
• ALT (alanine aminotransferase) blood test
• AST (aspartate aminotransferase) blood test
• BUN (blood urea nitrogen) test
• Potassium blood test
• PSA (prostate-specific antigen) test
• D-dimer test
• Hematocrit (HCT) test
• Hemoglobin (Hgb) blood test

General reference, not medical advice. Reference ranges vary by laboratory and by individual — the range on your own report applies to you, and a licensed clinician should interpret your results.