Lab values
Normal Electrolyte and Chemistry Lab Values
Adult reference ranges in US units with the SI equivalent. Ranges differ a little between labs; use your lab’s printed range.
| Test | US units | SI units | Notes |
|---|---|---|---|
| Sodium | 135–145 mEq/L | 135–145 mmol/L | |
| Potassium | 3.5–5.0 mEq/L | 3.5–5.0 mmol/L | |
| Chloride | 98–107 mEq/L | 98–107 mmol/L | |
| Bicarbonate (CO₂, serum) | 23–29 mEq/L | 23–29 mmol/L | |
| Calcium, total | 8.8–10.3 mg/dL | 2.20–2.58 mmol/L | Correct for low albumin; many review books use 9.0–10.5 |
| Calcium, ionized | 4.7–5.2 mg/dL | 1.17–1.30 mmol/L | |
| Magnesium | 1.7–2.2 mg/dL | 0.70–0.91 mmol/L | Many review books give 1.3–2.1 mEq/L |
| Phosphorus | 2.8–4.5 mg/dL | 0.90–1.45 mmol/L | |
| Glucose, fasting | 70–99 mg/dL | 3.9–5.5 mmol/L | |
| Hemoglobin A1c | Below 5.7% | Below 39 mmol/mol | 5.7–6.4% prediabetes; 6.5% or higher diabetes SI: 39–47 mmol/mol prediabetes; 48 or higher diabetes |
| BUN | 6–20 mg/dL | 2.1–7.1 mmol/L | |
| Creatinine | 0.7–1.3 mg/dL (men), 0.6–1.1 mg/dL (women) | 62–115 µmol/L (men), 53–97 µmol/L (women) | |
| Serum osmolality | 285–295 mOsm/kg | 285–295 mmol/kg | |
| Lactate | 0.5–2.0 mmol/L | 0.5–2.0 mmol/L | Above 2 in sepsis needs a repeat; 4 or higher signals shock |
Study the labs
- ABG Interpretation in 6 StepspH, PaCO₂, HCO₃⁻, compensation, anion gap and oxygenation, with worked examples
- Electrolyte ImbalancesNa, K, Ca, Mg and phos: normals, ECG clues, safe replacement, hyperkalemia steps
- Pediatric Assessment and EmergenciesPAT, vital signs, airway infections, febrile seizures, dehydration, arrest, choking and abuse
- Bleeding, Reversal, HIT and DICAnticoagulant reversal, the 4Ts and HIT care, DIC and TTP for critical care exams
Other lab values
- Hematology
- Coagulation
- Arterial blood gas
- Liver and pancreas
- Cardiac
- Therapeutic drug levels
- Urine
- Pediatric vital signs by age
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Sources
- MedlinePlus Medical Encyclopedia ranges (National Library of Medicine, reviewed 2024–2026); ABIM laboratory reference ranges (January 2026) for hemoglobin, hematocrit and potassium; Merck Manual for ionized calcium; the heparin label for the aPTT target; ASHP/IDSA 2020 vancomycin guideline
For education and exam preparation only. Follow your institution’s protocols. Typical adult values for study. Follow the order, the label and your institution's protocols.