5. Performance Monitoring of Primary and Secondary Reference Laboratories:

Monthly surveys are administered by the CPRL to monitor performance of the network Primary and Secondary Reference Laboratories, as well as Level 1 certified laboratories. Each month, the CPRL ships 10 fresh or fresh-frozen whole blood specimens over the desired clinical range (4-12% HbA1c) to each network laboratory within 2 days of collection. The CPRL and/or each PRL prepares hemolysates following the CPRL sample preparation procedure (aliquots of each hemolysate may be frozen at -70oC or colder prior to assay). Each SRL prepares samples following their method protocol. The CPRL, PRLs and SRLs analyze the specimens in two separate runs on two separate days. All data is sent to the NETCORE for analysis. Each Level 1-certified laboratory receives monitoring specimens quarterly.

To maintain certification, a network (PRL and SRL) or Level 1 laboratory must fulfill the following bias and precision requirements: 1) the mean of the differences (n=10) between the network laboratory and the CPRL must not exceed 0.35% HbA1c and 2) the estimate of the standard deviation of the difference in sample replicates must not exceed 0.229 (99th percentile of the sampling distribution around a target SD of 0.15). All results outside these limits are investigated. All monitoring results are shared among network laboratories.