Lab reference ranges
The ranges the MagstoneRN study guides use, each with its source and the population it applies to. If your program's table differs, use your program's values on its exams.
| Test | Range | Unit | Population |
|---|---|---|---|
| Sodium[1] | 136-145 | mEq/L | all ages |
| Potassium[2] | 3.5-5.1 | mEq/L | all ages |
| Chloride[3] | 98-107 | mEq/L | all ages |
| Calcium[4] | 8.8-10.2 | mg/dL | all ages |
| Magnesium[5] | 1.6-2.6 | mg/dL | all ages |
| Phosphate[6] | 0.8-1.5 | mmol/L | teaching table, population not stated |
| BUN (urea nitrogen)[7] | 6-20 | mg/dL | all ages |
| Creatinine, female[8] | 0.50-1.00 | mg/dL | female |
| Creatinine, male[8] | 0.70-1.20 | mg/dL | male |
| Glucose[9] | 62-125 | mg/dL | all ages; a fasting 126 or higher is diabetes |
| Hemoglobin A1C[10] | 4.0-5.6 | % | all ages |
| Hemoglobin A1C, prediabetes[10] | 5.7-6.4 | % | diagnostic cutoff, not a normal range |
| Hemoglobin A1C, diabetes[10] | 6.5 or higher | % | diagnostic cutoff, not a normal range |
| Albumin[11] | 3.9-5.2 | g/dL | all ages |
| Total bilirubin[12] | 0.0-1.1 | mg/dL | age 1 month and older |
| Serum osmolality[13] | 275-295 | mmol/kg | population not stated |
| White blood cells[14] | 4,500-10,000 | cells/mcL | adults |
| Hemoglobin, adult women[14] | 12-15 | g/dL | adult women |
| Hemoglobin, adult men[14] | 14-17 | g/dL | adult men |
| Hematocrit, adult women[14] | 36-44 | % | adult women |
| Hematocrit, adult men[14] | 41-50 | % | adult men |
| Platelets[14] | 140,000-450,000 | cells/mcL | adults |
| PT (prothrombin time)[6] | 11-14 | seconds | teaching table, population not stated |
| INR[6] | 0.9-1.2 | No unit | teaching table, population not stated |
| INR target on warfarin, DVT, PE or non-valvular atrial fibrillation[15] | 2.0-3.0 | No unit | DVT, PE or non-valvular atrial fibrillation |
| INR target on warfarin, mechanical mitral valve (tilting disk or bileaflet), or caged ball or caged disk valve[15] | 2.5-3.5 | No unit | mechanical mitral valve (tilting disk or bileaflet), or caged ball or caged disk valve |
| aPTT[6] | 20-40 | seconds | teaching table, population not stated |
| aPTT target on heparin[16] | 1.5-2 | times normal | full-dose heparin |
| pH, arterial[6] | 7.35-7.45 | No unit | teaching table, population not stated |
| PaCO2[6] | 35-45 | mm Hg | teaching table, population not stated |
| HCO3 (bicarbonate)[17] | 22-26 | mEq/L | age 1 month and older |
| PaO2[6] | 80-100 | mm Hg | teaching table, population not stated |
| SaO2[13] | 95-100 | % | adults |
Sources for the table
- Sodium, default method (reference interval effective September 14, 2026) (opens in a new tab). UW Medicine Laboratory Test Guide. License: Not openly licensed; reference values cited as facts, no text reused. Accessed October 18, 2026.
- Potassium, default method (reference interval effective September 14, 2026) (opens in a new tab). UW Medicine Laboratory Test Guide. License: Not openly licensed; reference values cited as facts, no text reused. Accessed October 18, 2026.
- Chloride, default method (reference interval effective September 14, 2026) (opens in a new tab). UW Medicine Laboratory Test Guide. License: Not openly licensed; reference values cited as facts, no text reused. Accessed October 18, 2026.
- Calcium, default method (reference interval effective September 14, 2026) (opens in a new tab). UW Medicine Laboratory Test Guide. License: Not openly licensed; reference values cited as facts, no text reused. Accessed October 18, 2026.
- Magnesium, default method (reference interval effective September 14, 2026) (opens in a new tab). UW Medicine Laboratory Test Guide. License: Not openly licensed; reference values cited as facts, no text reused. Accessed October 18, 2026.
- Health Alterations, Appendix A: Normal Reference Ranges (opens in a new tab). Open RN, Chippewa Valley Technical College (2024). License: CC BY 4.0. Accessed October 18, 2026.
- Urea nitrogen, default method (reference interval effective September 14, 2026) (opens in a new tab). UW Medicine Laboratory Test Guide. License: Not openly licensed; reference values cited as facts, no text reused. Accessed October 18, 2026.
- Creatinine, default method (reference interval effective September 14, 2026) (opens in a new tab). UW Medicine Laboratory Test Guide. License: Not openly licensed; reference values cited as facts, no text reused. Accessed October 18, 2026.
- Glucose, default method (reference interval effective September 14, 2026) (opens in a new tab). UW Medicine Laboratory Test Guide. License: Not openly licensed; reference values cited as facts, no text reused. Accessed October 18, 2026.
- Hemoglobin A1C by HPLC (reference interval effective October 1, 2024) (opens in a new tab). UW Medicine Laboratory Test Guide. License: Not openly licensed; reference values cited as facts, no text reused. Accessed October 18, 2026.
- Albumin, default method (reference interval effective September 14, 2026) (opens in a new tab). UW Medicine Laboratory Test Guide. License: Not openly licensed; reference values cited as facts, no text reused. Accessed October 18, 2026.
- Total bilirubin (Roche) (reference interval effective September 2, 2026) (opens in a new tab). UW Medicine Laboratory Test Guide. License: Not openly licensed; reference values cited as facts, no text reused. Accessed October 18, 2026.
- Nursing Fundamentals, 2nd edition, Chapter 15: Fluids and Electrolytes (opens in a new tab). Open RN, Chippewa Valley Technical College (2024). License: CC BY 4.0. Accessed October 18, 2026.
- Blood Tests (last updated March 24, 2022) (opens in a new tab). National Heart, Lung, and Blood Institute, NIH. License: Public domain (U.S. government work). Accessed October 18, 2026.
- Jantoven (warfarin sodium) tablets, prescribing information (DailyMed version 13, July 8, 2025) (opens in a new tab). Upsher-Smith Laboratories, on DailyMed (National Library of Medicine). License: U.S. drug label published on DailyMed; facts cited, no text reused. Accessed October 18, 2026.
- Heparin sodium injection, prescribing information (DailyMed version 8, August 15, 2025) (opens in a new tab). Fresenius Kabi USA, on DailyMed (National Library of Medicine). License: U.S. drug label published on DailyMed; facts cited, no text reused. Accessed October 18, 2026.
- Bicarbonate, whole blood (reference interval effective August 2, 2011) (opens in a new tab). UW Medicine Laboratory Test Guide. License: Not openly licensed; reference values cited as facts, no text reused. Accessed October 18, 2026.