A miniaturized self-contained single-use disposable quantitatitve test for hemoglobin A1c in blood at the point of care.

DRx HbA1c is a finger-stick (< or =10 microL) test for hemoglobin A1c (HbA1c) developed by Metrika, Inc., for rapid quantitative testing at the point of care. It incorporates microelectronics, optics, and dry reagent chemistry inside a self-contained, integrated, single-use device. Test results (%HbA1c) are displayed in numeric form on the device's liquid crystal display within 8 min after sample application. Having no switches or buttons, DRx HbA1c self-activates upon addition of sample. It contains two dry reagent lateral flow strips, each having an HbA1c immunoassay test zone and a total hemoglobin (Hb) test zone. An on-board microprocessor calculates %HbA1c from the reflectances of the test zones. The microprocessor also corrects for lot-specific reagent characteristics and optical variation, in addition to checking electrical functioning and proper sample volume. For testing accuracy, subjects both with and without diabetes were recruited in order to obtain samples with a wide range of HbA1c values. Whole blood samples were analyzed using both DRx HbA1c units and a laboratory method (Bio-Rad DiaSTATT). DRx HbA1c testing was performed by laboratory personnel and by subjects who received brief training. Repeatability, linearity, sample volume tolerance, diluted sample stability and hematocrit tolerance of the DRx HbA1c test were assessed by trained laboratory personnel as described in the text. The linear %HbA1c range of the assay extended from approximately 3% to 15%. Hb was measurable from 6.8 to 20.0 g/dL, encompassing over 99.8% of the normal population. DRx HbA1c clinical sample test results (n = 50) correlated linearly to the Bio-Rad DiaSTAT method (r = 0.935) with slope and intercept values of 0.994 and 0.003, respectively. The repeatability for %HbA1c was within 5-9% CV. We conclude that DRx HbA1c performance is closely equivalent to that of existing tests.

Cholesterol in fingerstick capillary specimens can be equivalent to conventional venous measurements.

Current interest in coronary heart disease and cholesterol has led to the development of a new generation of compact analysis systems designed for fingerstick whole blood measurement. Since reliable classification of patients based on national cut-points for serum cholesterol concentration requires accurate results, the question whether results from fingerstick capillary specimens are equivalent to those from conventional venous-derived serum specimens, the basis for the national cut-points, is germane. Earlier studies in the literature are contradictory, with fingerstick differences ranging from 9% low to 6% high. We developed guidelines for reliable fingerstick collection and, following these guidelines, achieved results that were comparable to results derived from concurrently collected venous serum specimens. Results measured either by an accurate, standardized enzymatic assay or by the AccuMeter, a new noninstrumented device, were in close agreement with serum results, ie, within 1% and 1.7%, respectively, suggesting that fingerstick measurements are appropriate for identifying individuals with elevated cholesterol levels and monitoring their treatment.