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Using standardized serum creatinine values in the modification of diet in renal disease study equation for estimating glomerular filtration rate.

BACKGROUND: Glomerular filtration rate (GFR) estimates facilitate detection of chronic kidney disease but require calibration of the serum creatinine assay to the laboratory that developed the equation. The 4-variable equation from the Modification of Diet in Renal Disease (MDRD) Study has been reexpressed for use with a standardized assay. OBJECTIVE: To describe the performance of the revised 4-variable MDRD Study equation and compare it with the performance of the 6-variable MDRD Study and Cockcroft-Gault equations. DESIGN: Comparison of estimated and measured GFR. SETTING: 15 clinical centers participating in a randomized, controlled trial. PATIENTS: 1628 patients with chronic kidney disease participating in the MDRD Study. MEASUREMENTS: Serum creatinine levels were calibrated to an assay traceable to isotope-dilution mass spectrometry. Glomerular filtration rate was measured as urinary clearance of 125I-iothalamate. RESULTS: Mean measured GFR was 39.8 mL/min per 1.73 m2 (SD, 21.2). Accuracy and precision of the revised 4-variable equation were similar to those of the original 6-variable equation and better than in the Cockcroft-Gault equation, even when the latter was corrected for bias, with 90%, 91%, 60%, and 83% of estimates within 30% of measured GFR, respectively. Differences between measured and estimated GFR were greater for all equations when the estimated GFR was 60 mL/min per 1.73 m2 or greater. LIMITATIONS: The MDRD Study included few patients with a GFR greater than 90 mL/min per 1.73 m2. Equations were not compared in a separate study sample. CONCLUSIONS: The 4-variable MDRD Study equation provides reasonably accurate GFR estimates in patients with chronic kidney disease and a measured GFR of less than 90 mL/min per 1.73 m2. By using the reexpressed MDRD Study equation with the standardized serum creatinine assay, clinical laboratories can report more accurate GFR estimates.

Pubmed ID: 16908915


  • Levey AS
  • Coresh J
  • Greene T
  • Stevens LA
  • Zhang YL
  • Hendriksen S
  • Kusek JW
  • Van Lente F
  • Chronic Kidney Disease Epidemiology Collaboration


Annals of internal medicine

Publication Data

August 15, 2006

Associated Grants

  • Agency: NIDDK NIH HHS, Id: UO1 DK 053869
  • Agency: NIDDK NIH HHS, Id: UO1 DK 067651
  • Agency: NIDDK NIH HHS, Id: UO1 DK 35073

Mesh Terms

  • Adult
  • Biological Markers
  • Creatinine
  • Female
  • Glomerular Filtration Rate
  • Humans
  • Male
  • Middle Aged
  • Models, Biological
  • Randomized Controlled Trials as Topic
  • Renal Insufficiency, Chronic