Abstract
Point-of-care HbA1c analysers are increasingly used to give patients an immediate result at the diabetes clinic visit, but method
agreement against the laboratory reference method is not always re-verified once a device is in routine use rather than under
initial validation conditions. We compared paired point-of-care and laboratory HbA1c results from 412 patients across three
clinics using the same point-of-care analyser model. Overall agreement was good (mean bias 0.06%, limits of agreement -0.32%
to 0.44%), but one of the three clinics showed a consistent positive bias of 0.31% traced to an expired calibration cartridge lot
that had not been flagged by the device's own expiry check. We report the bias findings by clinic and the cartridge fault that
explained the outlier, as a short, practical record of what a routine method-agreement recheck can catch that initial validation
cannot.
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