In order to evaluate a novel technique for measuring haemoglobin A1c using a cassette-based immunoassay method we have undertaken a laboratory evaluation using 48 patient samples and a separate within-clinic prospective study of 59 diabetic patients. Individuals were recruited from general (48 patients), paediatric (19 patients), obstetric (24 patients), and general practice (15 patients) diabetic clinics. Agreement was evaluated between HbA1c results obtained using the new method (AMES DCA 2000) and an established laboratory assay (DIAMAT HPLC system). The mean differences between the two results (AMES DCA 2000-DIAMAT) (95% confidence intervals) were: laboratory -0.69% (-1.42 to 0.04%); paediatric clinic -0.93% (-1.93 to 0.07%); obstetric clinic -0.29% (-1.09 to 0.51%), and general practice clinic -0.77% (-1.3 to -0.24%). For the AMES DCA 2000, the coefficient of variation for HbA1c of 5.2% was 1.6% and for HbA1c of 13%, 2.4%. This instrument was used without difficulty by four different operators. Intra-assay coefficient of variation for each operator was < 3.4%. In 9/18 patients where a specific assessment of clinical utility was made, knowledge of the HbA1c result at the time of consultation lead to a change in treatment. Methodology of this type may be used successfully within a diabetic clinic setting in both primary care and hospital environments.