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Indicator Details: Estimating Equations Used by Laboratories Reporting eGFRa,b
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  • CAP

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a For purposes of interest in equation uptake, Original MDRD-4 and IDMS MDRD-4 were combined into MDRD-4.

b For the years 2006–2007 and 2010, Not Sure and Other were combined into Other.

In 2019, more than half (61%) of surveyed laboratories that were reported eGFR used the recommended 4-parameter MDRD Study estimating equation to calculate eGFR.

Chart Explanation: 

The majority of surveyed laboratories that reported eGFR used the NKDEP-recommended 4-parameter MDRD Study equation (61%) to estimate GFR. Other laboratories used other equations: CKD-EPI (31%), MDRD-6 (2%), C-G (2%), or Other (3%).

In June 2006, 2007, 2008, 2011-2013, 2017, and 2019, the College of American Pathologists (CAP) performed its General Chemistry Survey, in which all CAP-accredited laboratories that performed routine chemistries (representing an estimated 80% or more of US laboratories performing routine chemistries) were queried regarding their eGFR reporting practices (response rates were 60%, 76%, and 77% in 2007, 2008, and 2009, respectively). In a supplemental survey, laboratories were asked “Does your institution report an estimated Glomerular Filtration Rate (GFR) based on a serum or plasma creatinine measurement without measuring urine creatinine?” (yes/no); “If yes, when do you report the estimated GFR?” (with all measured serum or plasma creatinine determinations/only when specifically requested/other); and “If your institution reports an estimated GFR, what formula is used?” (4-parameter MDRD Study equation/6-parameter MDRD Study equation/Cockcroft-Gault/not sure/other). In the creatinine accuracy calibration survey, which is purchased by laboratories for self-assessment, CAP asked participants to state their creatinine calibration method: IDMS-traceable versus traditional calibration. Note that manufacturers were polled in June 2009; it was found that all major global manufacturers are currently only distributing IDMS-traceable serum creatinine methods (as of the end of 2009) in all markets they serve. All existing lots of older calibration reagents should be used up during 2010 (exceptions: the Siemens Dimension/Vista Jaffe method which will continue with its current calibration traceability and the Nova Biomedical blood gas instrument creatinine measurement). Some smaller manufacturers were not represented in the survey but all major North American and global manufacturers responded (Miller, 2009).

Description of MeasureLaboratory reporting of eGFR
Data Source

College of American Pathologists

Type of Data SourcePrivate
Data SetLaboratory survey results
Health Care System DataNo
Regional or National?National
Demographic GroupRepresentative sample of accredited laboratories in the CMS CLIA database with a specialty in routine chemistry testing who responded to survey
NumeratorLaboratories that reported eGFR with serum creatinine
DenominatorRepresentative sample of accredited laboratories that responded to survey
Glomerular filtration rateMethod of estimation of GFR varied by laboratory and was part of survey
Primary Data Source IndicatorProportion of U.S. laboratories that reported eGFR with serum creatinine
Primary Indicator Method of MeasurementSurvey
Frequency of Measurement (Primary)

2006-2007, annually from 2010-2013, and then 2017 and 2019 (cross-sectional) for chemistry survey.

U.S. Region Covered by Primary VariableAll
Period Currently Available


Pending Data


Additional Data Items of InterestMethod of estimation, reporting standards, frequency of reporting, type of laboratory, volume of testing
Limitations of IndicatorOnly those laboratories of the sample that responded to the survey were included; recall bias
Analytical ConsiderationsMethod, standards & frequency can only be obtained within those reporting serum creatinine and eGFR
References and Sources:
  • Miller WG, Bachmann LM, Delanghe JR, Inker LA, Jones GRD, Vassalotti JA. Optimal use of biomarkers for chronic kidney disease. Clin Chem. 2019;65(8):949-955.
  • Miller WG, Bruns DE, Hortin GL, et al. Current issues in measurement and reporting of urinary albumin excretion. Clin Chem 2009;55:24-38.
  • National Kidney Foundation. K/DOQI clinical practice guidelines for chronic kidney disease: evaluation, classification, and stratification. Kidney Disease Outcome Quality Initiative. Am J Kidney Dis 2002;39:S1–246.
  • Levey AS, Coresh J, Greene T, et al. Expressing the modification of diet in renal disease study equation for estimating glomerular filtration rate with standardized serum creatinine values. Clin Chem 2007;53:766-72.
  • Levey AS, Stevens LA, Schmidet CH, et al. A new equation to estimate glomerular filtration rate. Ann Intern Med. 2009;150:604-12.
  • KDIGO Clinical Practice Guideline for the Evaluation and Management of Chronic Kidney Disease. Kidney Int Suppl 2013;3:1-150.
  • Inker LA, Astor BC, Fox CH, et al. KDOQI US commentary on the 2012 KDIGO clinical practice guideline for the evaluation and management of CKD. Am J Kidney Dis. 2014;63(5):713-735.
  • Miller WG, Myers GL, Ashwood ER, et al. Creatinine measurement: state of the art in accuracy and inter-laboratory harmonization. Arch Pathol Lab Med 2005;129:297-304.
  • Shafi T, Matsushita K, Selvin E, et al. Comparing the association of GFR estimated by the CKD-EPI and MDRD study equations and mortality: the third national health and nutrition examination Survey (NHANES III). BMC Nephrol. 2012;13:42.

  • https://www.niddk.nih.gov/health-information/communication-programs/nkdep/workinggroups/ laboratory.

Suggested Citation:
Centers for Disease Control and Prevention. Chronic Kidney Disease Surveillance System—United States.
website. http://www.cdc.gov/ckd