External Quality Assessment of HbA1c for Point of Care Testing

Abstract

Objectives. To evaluate the long term total imprecision of HbA1c testing within the county of Uppsala in relation to the Swedish analytical goal of coefficient of variation (CV) <3% for HbA1c and to study the cost of an external quality assurance program for point-of-care HbA1c The county uses Bayer DCA 2000TM for point-of care HbA1c testing currently having 23 of these instruments.

Methods. Method imprecision was assessed by analysis of patient samples performed as split samples during a 3 year period (2002-2004) as part of the quality assurance program for point-of-care HbA1c testing. The samples were first analysed on a Bayer DCA 2000TM and the samples were then sent to the centralised laboratory for reanalysis with an HPLC system (Variant IITM, Biorad). The testing was performed approximately 8 times per year with each instrument.

Results. The median CV between the HPLC method and the point-of-care instruments for each unit was slightly higher than 3%.

Conclusion. The DCA 2000TM systems have an acceptable imprecision and agreement with the central laboratory. The test results show acceptable agreements within the county regardless where the patient is tested. The cost of the external quality assurance program is calculated to be approximately SEK 1340 (Euro 150) per instrument.