CDC Surveillance System: Laboratory Reporting of eGFR Using Creatinine

Automatic laboratory reporting of eGFR with serum creatinine has been increasing over time; overall, 92% of surveyed College of American Pathologists (CAP)-accredited laboratories reported eGFR with serum creatinine in 2019 (vs. 89% in 2017).

Chart Explanation:

In 2019, the percentage of laboratories accredited by the College of American Pathologists (CAP) reporting eGFR with serum creatinine measurements slightly increased. A total of 92% of the 6,217 laboratories that responded reporting eGFR with serum creatinine, with a slight 3% increase from 2017 but a substantial increase from 2005 when only 20% of survey respondents reported eGFR with creatinine.

The College of American Pathologists (CAP) performs regular surveys of CAP-accredited laboratories. In June of 2003, 2005, and 2007, annually from 2008 to 2013, 2017, and 2019 CAP included in its General Chemistry Survey, in which all CAP-accredited laboratories that performed routine chemistries (representing an estimated 80% or more of U.S. laboratories performing routine chemistries) were sent a questionnaire regarding their eGFR reporting practices (2019 n=6,217 responding laboratories).

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/IDMS-traceable 4-parameter MDRD Study equation (added 2011)/6-parameter MDRD Study equation/CKD-EPI equation (added 2011)/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 have been 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 inquiry but all major North American and global manufacturers responded (Miller, 2009; http://nkdep.nih.gov/labprofessionals/Clinical_Laboratories.htm).

Field	Data
Description of Measure	Laboratory reporting of eGFR
Data Source	College of American Pathologists
Type of Data Source	Private
Data Set	General Chemistry Survey results
Health Care System Data	No
Regional or National?	National
Demographic Group	CAP-accredited laboratories performing general chemistry who responded to surveys
Numerator	CAP-accredited laboratories who reported eGFR
Denominator	CAP-accredited laboratories who responded to survey
Glomerular filtration rate	Method of estimation of GFR varied by laboratory and was part of survey
Primary Data Source Indicator	Number of U.S. CAP-accredited laboratories who performed general chemistry and reported eGFR/IDMS-traceable calibration
Primary Indicator Method of Measurement	Survey
Frequency of Measurement (Primary)	Bi-annual to 2007, annual from 2008 to 2013, and then 2017 and 2019 (cross-sectional) for chemistry survey
U.S. Region Covered by Primary Variable	All; some international laboratories (unknown %) included
Period Currently Available	2019
Pending Data	2020
Additional Data Items of Interest	Method of estimation, reporting standards, frequency of reporting
Limitations of Indicator	Only those laboratories who chose to participate (who performed general chemistry including creatinine) and responded to the survey were included (response rate 60-77%, depending on survey year); recall bias; international labs included; for creatinine calibration, lab may be unfamiliar with manufacturer’s calibration practice; unknown representativeness of CAP laboratories (although estimated at >80% of U.S. labs); number of laboratories do not represent volume of patients; IDMS-traceable MDRD and CKD-EPI equations only added in later surveys
Analytic Considerations	Denominator should be defined if possible. Method, standards & frequency can only be obtained within those reporting eGFR/IDMS-traceable calibration

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):949–55.
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;53:766–772.
Levey AS, Stevens LA, Schmid 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