Table 2.

CKD Biomarkers Consortium QC procedures

Category of QC ProceduresProcedure
Historical performance measuresEach laboratory that performs assays provided the following information to the QC committee:
 Laboratory accreditation (e.g., CLIA, CAP); for laboratories with no accreditation, information about the experience and qualifications of the supervisory staff and testing personnel was requested
 Instrument to be used for each analyte
 Experience with the particular instrument
 A description of measurement procedures on that instrument
 Westgard or other internal QC rules followed for acceptance of analytical batches
 Type and source of internal QC pools used for the measurement procedure
 Mean, SD, and percent coefficient of variation and recovery for the analyte
Sample preparation and handlingEach laboratory that prepared samples for assay provided the following information to the Consortium Coordinating Center or to the QC committee:
 List of specimens with sample identities and collection date for establishing a tracking database
 Procedures to be followed when preparing sample aliquots
 Procedures to be followed to randomize sample sequence for aliquoting, when feasible
 Procedures for selecting blind replicate samples. Laboratories were encouraged to provide replicates for 2% of the study samples or a minimum of 50 replicates per assay. Linkage information was maintained at the Consortium Coordinating Center and was not shared with the laboratories performing the assays
Prospective quality assuranceEach laboratory that performs assays provided the following information during and after completing each assay:
 Electronic listing of QC results and study data for the purpose of generating standardized internal and external QC reports
 Results of proficiency testing of QC pools of sufficient size to last the duration of consortium testing. These pools were collected from patients at various stages of CKD. Aliquots from these pools were added to the samples that were assayed to test for any drift in the assay
  • QC, quality control; CLIA, Clinical Laboratory Improvement Amendments; CAP, College of American Pathologists.