Advances in Hemoglobin A1c Point of Care Technology

Abstract

Measurement of hemoglobin A1c (A1C) has long been accepted as the best indicator of glucose control over time. Assays for A1C use technologies based on either charge differences (high-pressure liquid chromatography) or structure (boronate affinity or immunoassay combined with general chemistry). These technologies are generally employed in expensive laboratory instruments. More recently, A1C technology has been incorporated into point of care (POC) devices, allowing for immediate availability of A1C measurements, greatly facilitating diabetes care in both specialist and general practices. POC A1C tests should have acceptable performance, standardization to national reference, National Glycohemoglobin Standardization Program (NGSP) certification, simple operation without need for costly instrumentation, and Clinical Laboratory Improvement Amendments (CLIA) waiver. CLIA-waived POC technology includes Bio-Rad MicroMat II (distributed by Cholestech as GDX) and the Axis-Shield Afinion, both of which utilize boronate affinity. The DCA 2000(R)+ utilizes combined immunoassay and general chemistry. These instruments cost $1000 to $3000 and require regular maintenance, making them appropriate only for high-volume physician offices. The newly improved A1CNow+ also utilizes combined immunoassay and general chemistry, but the small, inexpensive, disposable monitor can be used by patients as well as by health care professionals. The new version of A1CNow+ has improved performance through recent introduction of automated solid state chemistry manufacturing, improved fluidics and automated assembly of the test cartridge, error-correcting software, and unitary meter calibration with factory calibration directly to the NGSP reference standard.

Evaluation of an Over-the-Counter Glycated Hemoglobin (A1C) Test Kit

“…10 The A1CNow+ test kit has been shown to be accurate in POC monitoring of A1C levels. 8,9 The objectives of the current study were to evaluate the performance of the device in the hands of untrained lay users as an OTC application and to evaluate comprehension of the written instructional materials (with and without a training DVD) that are provided with the system. The 13.5% cutoff used to determine accuracy of the A1C readings in this study represents the upper 95% limit on total error and is based on allowing for variation in calibration accuracy and precision of both the test and reference methods.…”

“…8 Validation studies have shown the A1CNow+ ® POC assay (Bayer HealthCare LLC, Diabetes Care, Tarrytown, NY) to be comparable to laboratory reference measurements. 8,9 Point-of-care assays may be modified to be appropriate for over-the-counter (OTC) use, provided they are relatively simple to perform; the results are clear to the user; and they are approved for at-home use. 10 The A1CNow ® SELFCHECK (Bayer HealthCare LLC, Diabetes Care, Tarrytown, NY) is a fully integrated, hand-held device for the quantification of percentage of A1C in capillary (finger stick) whole blood and is currently approved for OTC use.…”

“…7 Advances in physician and patient access to A1C monitoring have the potential to benefit the majority of patients with diabetes. 8 Validation studies have shown the A1CNow+ ® POC assay (Bayer HealthCare LLC, Diabetes Care, Tarrytown, NY) to be comparable to laboratory reference measurements. 8,9 Point-of-care assays may be modified to be appropriate for over-the-counter (OTC) use, provided they are relatively simple to perform; the results are clear to the user; and they are approved for at-home use.…”

Screening for diabetes in dental settings

“…The kit then took five minutes to analyse the blood sample, after which time the participants HbA1c result is displayed as a percentage. A1CNow+ is accessible, accurate, and easy to use (Bode, Irvin, Pierce, Allen, & Clark, 2007 Demographics Questionnaire -A demographics questionnaire was designed to collect participant information such as gender, ethnicity, age, and GP information. This information was required for statistical purposes and so the GP of the participants' who took part could be contacted to inform them of their patients' involvement in the study and of their screening results (see appendix 5).…”

“…It is a small, portable, disposable handheld immunoassay device which is certified by the National Glycohemoglobin Standardisation Programme, and is Clinical Laboratory Improvement Amendments (CLIA) waived. Requiring no calibration, it uses a small (5μl) blood sample that is mixed with a reagent provided with the test kit, and then transferred with a pipette to a sample well in the testing device (Bode et al, 2007). Results are then provided in 5 minutes.…”