Creatinine Clearance — Schwartz Estimate Revised

All calculations should be independently verified prior to clinical use. These calculators are intended to supplement, not replace, clinical judgment.

Estimate glomerular filtration rate (creatinine clearance) from serum creatinine and height using the 2009 revised Schwartz equation, validated for IDMS-calibrated enzymatic creatinine measurements.

Creatinine method matters: This formula applies to enzymatic serum creatinine measurements calibrated by isotope dilution mass spectrometry (IDMS). Do not use with alkaline picrate (“Jaffé”) methods, even those traceable to IDMS. Hemolyzed samples or elevated bilirubin may artifactually lower creatinine measurements. For non-IDMS creatinine, use the original Schwartz Estimate.

Serum creatinine mg/dL

Height cm in

GFR mL/min/1.73 m²

The 2009 revised Schwartz formula uses a single fixed proportionality constant of 0.413, derived from measured GFR data in children with chronic kidney disease using IDMS-calibrated creatinine:

GFR = 0.413 × Ht ÷ Cr_serum

Height is in cm and serum creatinine is in mg/dL. Creatinine must be at steady state. This formula is most accurate in the range of 15–75 mL/min/1.73 m²; values above 75 should be reported as “> 75” rather than as a specific number per NKDEP guidance.

Unlike the original Schwartz formula, no age- or sex-specific constant is required — 0.413 applies uniformly across pediatric patients. Many medications require dose adjustment when GFR falls below 50 mL/min.

For a timed urine collection method see Creatinine Clearance — Measured.

Special thanks to Dr. Megan Rashid, University of Rochester.

References

Schwartz GJ, Muñoz A, Schneider MF, Mak RH, Kaskel F, Warady BA, Furth SL. New equations to estimate GFR in children with CKD. J Am Soc Nephrol. 2009;20(3):629–637.
National Kidney Disease Education Program. GFR reporting recommendations for laboratory professionals. Available at: NIDDK GFR resources.