The variability of results between point-of-care testing glucose meters and the central laboratory analyzer.

Context: Point-of-care testing glucose meters are strongly recommended in the management of diabetes and are increasingly being used for making therapeutically important decisions. Thus, it is essential that their results correlate well with those of laboratory analyzers.
Objectives: To test the reliability of point-of-care testing glucose meters.
Design: Two studies were performed: (1), an in-house study comparing accuracy of point-of-care testing glucose meters with a reference analyzer using fresh whole blood specimens (2), a real-time comparison of (a) 2 successive glucose meter readings and (b) glucose meter reading to central laboratory analyzer reading.
Setting: (1), Seven glucose meters from 4 manufacturers were compared with the Yellow Springs YSI 2300 blood glucose analyzer using whole blood without preservative. (2), (a) Whole blood samples were read within 5 minutes of each other using Accu-Chek meters and (b) between a glucose meter and a Hitachi laboratory analyzer.
Results: (1) Within the Accu-Chek group of glucose meters, fresh, preservative-free whole blood samples showed the lowest bias. (2) At the hypoglycemic level, successive glucose meter readings agreed well, but there was considerable disagreement between glucose meter and central laboratory values. Because laboratory analyzers are of proven accuracy, they are used as the reference. In the glucose meter-central laboratory analyzer correlation, for both hypoglycemic and hyperglycemic values, readings in which the differences were greater than 10% occurred more than 61% of the time. In the hypoglycemic range, differences greater than 20% occurred 57% of the time.
Conclusions: One should scrutinize point-of-care testing glucose meter readings at the hypoglycemic and hyperglycemic levels and whenever possible to corroborate these clinical results with central laboratory analyzers.