Analytic bias among certified methods for the measurement of hemoglobin A(1c)

作者：Holmes Earle W^*; Ersahin Cagatay; Augustine Geri J; Charnogursky Gerald A; Gryzbac Margie; Murrell Joanne V; McKenna Kathleen M; Nabhan Fadi; Kahn Stephen E

来源：American Journal of Clinical Pathology, 2008, 129(4): 540-547.

DOI：10.1309/U3GPPTCBP1VLL8AW

• hemoglobin A(1c)
• point-of-care testing
• analytic error
• diabetes

We studied the magnitude, significance, and origin of an analytic bias that emerged between our point-of-care (POC) and our central laboratory (CL) methods for the measurement of hemoglobin A(1c) (HbA(1c)) and evaluated the analytic accuracy of 7 commonly used HbA(1c) methods relative to the National Glycohemoglobin Standardization Program (NGSP) reference method. The POC and CL methods were compared by split-sample analysis of clinical specimens and time series analyses of the HbA(1c) results reported for a 33-month period. The relative accuracies of 7 HbA(1c) methods were evaluated using College of American Pathologists proficiency survey results. Long-term drifts in the CL- and POC-analyzed test results caused the median intermethod bias [(POC result) - (CL result) ] to increase from -0.4% to -0.9% HbA(1c). Systematic biases, drifts in analytic performance over time, and intermethod variability were frequently observed among the 7 NGSP-certified HbA(1c) methods. Intermethod variability is a potential source of inaccuracy whenever HbA(1c) results are interpreted relative to universal, fixed, clinical decision thresholds.

• 出版日期2008-4