Introduction
HbA1c point of care testing (PoCT) is a useful tool for the management of diabetic patients, particularly in rural and remote areas that do not have timely access to laboratory testing. The Roche cobas b 101 is a PoCT instrument for the measurement of HbA1c in capillary or venous whole blood. Approximately 2µL of blood is applied to the HbA1c test disc and a result is generated in under 6 minutes. We evaluated the accuracy and precision of the b 101 instrument and its usefulness as a diagnostic tool in diabetic patients.
Methods
Accuracy was evaluated in 10 primary health care settings by testing diabetic patient’s capillary whole blood samples on the cobas b 101 in parallel with venous samples sent to the local laboratory. Laboratory testing was performed by three different laboratory instruments. Diagnostic accuracy was determined by grouping patient results into diabetic (≥6.5%), pre-diabetic (5.7-6.4%) and non-diabetic (<5.7%) diagnosis. Precision was determined by testing quality control material supplied by the manufacturer.
Results
Samples tested showed good correlation between the cobas b 101 instrument and the laboratory analysers (r=0.98, n=132). Of the 62 lab classified diabetic patients, 100% were recognised as diabetic on the b101. Of the 50 lab classified pre-diabetic patients, 70% were recognised as pre-diabetic on the b101 and 30% as diabetic. Of the 20 lab classified normal patients, 60% were diagnosed as normal on the b 101 and 40% as pre-diabetic. Precision analysis on the cobas b101 gave average CV values <4%, meeting the recommendations set by the standards for PoCT in general practice.
Conclusions
Although comparisons were made across three different laboratory instruments the Roche cobas b 101 displayed good analytical performance and would be a suitable PoCT instrument for monitoring diabetic patients. It would also be suitable for diagnosis if HbA1c diagnosis is implemented in Australia.