Reference Lab Values
The normal ranges you look up mid-question — searchable. Matches the style of the official USMLE reference sheet.
Serum electrolytes & renal
| Sodium (Na⁺) | 136–145 mmol/L |
| Potassium (K⁺) | 3.5–5.0 mmol/L |
| Chloride (Cl⁻) | 95–105 mmol/L |
| Bicarbonate (HCO₃⁻) | 22–28 mmol/L |
| BUN | 7–18 mg/dL |
| Creatinine | 0.6–1.2 mg/dL |
| Glucose (fasting) | 70–100 mg/dL |
| Calcium (total) | 8.4–10.2 mg/dL |
| Magnesium | 1.5–2.0 mEq/L |
| Phosphorus | 3.0–4.5 mg/dL |
| Osmolality | 275–295 mOsm/kg |
Complete blood count
| Hemoglobin — male | 13.5–17.5 g/dL |
| Hemoglobin — female | 12.0–16.0 g/dL |
| Hematocrit — male | 41–53 % |
| Hematocrit — female | 36–46 % |
| Leukocytes (WBC) | 4,500–11,000 /mm³ |
| Platelets | 150,000–400,000 /mm³ |
| MCV | 80–100 fL |
| Reticulocytes | 0.5–1.5 % |
Liver & pancreas
| AST | 8–20 U/L |
| ALT | 8–20 U/L |
| Alkaline phosphatase | 20–70 U/L |
| Bilirubin, total | 0.1–1.0 mg/dL |
| Bilirubin, direct | 0.0–0.3 mg/dL |
| Albumin | 3.5–5.5 g/dL |
| Amylase | 25–125 U/L |
| Lipase | 10–140 U/L |
Arterial blood gas (room air)
| pH | 7.35–7.45 |
| PaCO₂ | 33–45 mmHg |
| PaO₂ | 75–105 mmHg |
| HCO₃⁻ (calculated) | 22–28 mmol/L |
Endocrine
| TSH | 0.4–4.0 µU/mL |
| Free T4 | 0.9–1.7 ng/dL |
| HbA1c | < 5.7 % |
| Cortisol (AM) | 5–23 µg/dL |
| Ca — see electrolytes | — |
Lipids & cardiac
| Total cholesterol | < 200 mg/dL |
| LDL | < 100 (optimal) mg/dL |
| HDL | > 40 (M) / > 50 (F) mg/dL |
| Triglycerides | < 150 mg/dL |
| Troponin I | < 0.04 ng/mL |
| BNP | < 100 pg/mL |
Coagulation
| PT | 11–15 sec |
| INR | 0.8–1.1 |
| aPTT | 25–40 sec |
| D-dimer | < 0.5 µg/mL |
| Fibrinogen | 200–400 mg/dL |
CSF
| Opening pressure | 70–180 mm H₂O |
| Glucose | 40–70 mg/dL |
| Protein | 15–45 mg/dL |
| Cell count (WBC) | 0–5 /mm³ |
Common adult reference ranges; institutions vary. The official exam provides its own values sheet on test day.