Creatinine (Cr)
RenalNormal range
M 0.6–1.2 mg/dL · F 0.5–1.1 mg/dL
SI: M 53–106 µmol/L · F 44–97 µmol/L
Critical high: > 4 mg/dL (context-dependent)
☎ When to call
Cr rising ≥ 0.3 from baseline, urine output < 0.5 mL/kg/hr × 6h, or any new oliguria — call before the next nephrotoxic dose, not after.
What you do
- The kidney number. A rise of 0.3 in 48h meets AKI criteria — small changes matter
- Check urine output — pair Cr with mL/kg/hr
- Review the MAR for nephrotoxins and renally-dosed drugs (vanco, enoxaparin, metformin)
- Anticipate holding contrast studies
Causes of HIGH creatinine
Causes of LOW creatinine
Source: Pagana, Mosby's Manual of Diagnostic and Laboratory Tests, 7th ed.; KDIGO AKI criteriaReference only — verify against your facility's policy.
