Retrospective analysis of 88,429 serum and urine glucose EQA results obtained from professional laboratories and medical offices participating in surveys organized by three European EQA centers between 1996 and 2007

Abstract

The analysis of glucose EQA results collected over a 12-year period showed that professional laboratories obtained better performances than medical offices, and that a general improvement in yearly performance was observed for both types of laboratories.

Retrospective analysis of 55,769 HbA1c EQA results obtained from professional laboratories and medical offices participating in surveys organized by two European EQA centers over a nine‐year period

“…Indeed, even if for center 1 some were not statistically significant, most of them were negative for the CV np % (CV np % reduction) and positive for the PoCR (PoCR increase). This suggests that there was a trend toward improved precision performances, as confirmed by findings of other studies 9, 22, 23. For center 2, with the same devices as in center 1, the trend was not clear, because only half the slopes indicated improved precision performances.…”

“…Furthermore, it was interesting to compare our CV np % with that of other studies. On the one hand, for professional laboratories, the CV np % obtained in this study with the Cobas Mira, Hitachi, and Integra groups of diagnostic devices are higher when compared with those obtained with the same devices in our previous study on the glucose parameter 9, showing that devices used for measuring glucose are more reproducible than those for HbA1c. On the other hand, the HbA1c CV np % calculated for DCA and Integra diagnostic devices are similar to the CV published by the College of American Pathologists in their 2010 GH2‐A survey 19.…”

“…The precision performances of medical offices were similar to those of professional laboratories for the two POCT devices (DCA and NycoCard). This is an interesting result, because in previous studies concerning other parameters professional laboratories obtained better results than medical offices 9, 15, 16.…”

“…Simple, nonparametric (np) statistics were chosen to analyze EQA results because they are well adapted to this type of data. Indeed, some studies 8–10 showed that they are not sensitive to extreme or aberrant results, which are frequently observed in EQA results. Sample conservation, calibration problems, method errors, samples exchange, and typing errors may in fact affect not only patients' 11 but also EQA results 12.…”

“…When available, we also selected the same diagnostic devices among the results provided by center 2, except for the Hitachi diagnostic devices (704, 717, and 912; Roche Diagnostics/Hitachi, Mannheim, Germany) with TinaQuant reagents (Roche). These latter devices were chosen because it was interesting to compare these results with those obtained in a previous study 9. We also studied the results provided by HPLC devices, the Menarini–Arkray HA‐8121 and HA‐8140 devices (Kyoto, Japan) and the Tosoh A1c 2.2 devices (Tokyo, Japan).…”