Lab values
Normal ABG 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 |
|---|---|---|---|
| pH | 7.35–7.45 | 7.35–7.45 | |
| PaCO₂ | 35–45 mm Hg | 4.7–6.0 kPa | |
| PaO₂ | 80–100 mm Hg | 10.7–13.3 kPa | |
| HCO₃⁻ | 22–26 mEq/L | 22–26 mmol/L | |
| SaO₂ | 95–100% | 95–100% |
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
- Lab Values to KnowNormal ranges in US units, therapeutic drug levels, and acting on a critical result
- Postpartum and Newborn NormalsFundus and lochia, BUBBLE-HE, PPH, Rh and vaccines, newborn vital signs, Apgar, jaundice, glucose, screening and discharge teaching
Other lab values
- Chemistry
- Hematology
- Coagulation
- Liver and pancreas
- Cardiac
- Therapeutic drug levels
- Urine
- Pregnancy and postpartum
- Newborn
- Pediatric vital signs by age
- Pediatric labs that differ from adults
Practice free in your browser2,150+ exam-style questions with rationales. No account, no ads. Also free on the App Store and Google Play.
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.