693 – Evaluation of In Vitro Diagnostics
Error Grid Analysis (EGA) of Glycated Hemoglobin A1c
Jesse Canchola
Roche Molecular Systems, Inc.
Error Grid Analysis (EGA) uses graphical error grids for performance evaluations of
medical devices, for example, a new device as compared to a predicate or currently
accepted or gold-standard device or for comparing candidate and comparative
measurement methodologies, for example, a new blood collection method as compared to
a current standard.
Although not as widely used, EGA is an instructive and visually appealing performance
evaluation methodology that shows the measurement of a new or improved test on the yaxis
with a paired measurement of the reference test on the x-axis overlaid on a colorful
grid of clinical regions (as established by experienced clinicians by consensus or through
findings in the literature). Although error grids for glucose (mg/dL and mmol/l),
hematocrit (%) and hemoglobin (g/dL) have been proposed, a reasonable EGA for
glycated hemoglobin A1c (HbA1c or, simply, A1c), in percent units, has not been widely
adopted at this time. We propose an EGA methodology for glycated hemoglobin A1c
(%).