Evaluation of an immunoturbidimetric assay for haemoglobin A1c on a Cobas Mira S analyser.

We evaluated a homogenous immunoturbidimetric assay for haemoglobin A1c (Tina-quant Haemog bin A1c, Boehringer Mannheim, GmbH, Mannheim, Germany) adapted to a Cobas Mira S analyser (F. Hoffmann-La Roche & Co., Basel, Switzerland) and not requiring sample pretreatment. Between-day CV's determined over a 6 week period were 5.9% and 5.3% for mean haemoglobin A1c values of 5.4% and 17.0% of total haemoglobin respectively. The imprecision was higher than with an in-house ion-exchange high performance liquid chromatographic method. Bilirubin, triacylglycerols and the labile fraction of haemoglobin A1c did not interfere with the assay of haemoglobin A1c. Fetal haemoglobin is not recognized by the antibodies used. Results correlated well with those obtained by high performance liquid chromatography. In conclusion, the Tina-quant assay is not prone to common interferences and allows the rapid and automated determination of haemoglobin A1c on open photometric analysers.