GFR Calculators

Use these GFR calculators to estimate kidney function for adults and children.

At this time, all laboratories should be using creatinine methods calibrated to be isotope dilution mass spectrometry (IDMS) traceable. In the US and other countries, nearly all methods from the major global manufacturers now have calibration traceable to an IDMS reference measurement procedure.¹ Consequently, the calculators for older non-standardized creatinine methods are no longer available on this web site. For more information on creatinine standardization, visit NKDEP’s Laboratory Professionals section.

GFR Calculator for Adults (for patients 18 and older)

In adults the recommended equation for estimating glomerular filtration rate (GFR) from serum creatinine is the Modification of Diet in Renal Disease (MDRD) Study equation. The IDMS-traceable version of the MDRD Study equation is used.

GFR Calculator for Children

Currently the best equation for estimating glomerular filtration rate (GFR) from serum creatinine in children is the Bedside Schwartz equation for use with creatinine methods with calibration traceable to IDMS²,³. Using the original Schwartz equation with a creatinine value from a method with calibration traceable to IDMS will overestimate GFR. Read additional laboratory guidelines on calculating estimated GFR for children.

Additional Resources

• Frequently Asked Questions About Estimated GFR Values

References

1. Miller WG. Estimating glomerular filtration rate. Clin Chem Lab Med 2009;47:1017–19).

2. Schwartz GJ, Muñoz A, Schneider MF, et al. New equations to estimate GFR in children with CKD. J Am Soc Nephrol. 2009:20(3):629–37.

3. Schwartz GJ and Work DF. Measurement and estimation of GFR in children and adolescents. J Am Soc Nephrol. 2009; Nov; 4(11): 1832–643.