The utilization of clinical laboratory test results in the diagnostic decision making process forms an essential aspect of clinical medicine. Inconsistent and unreliable laboratory test results may have severe effects on the health of the patient and society. The aim of this descriptive cross-sectional study was to evaluate the accuracy of most commonly used haemoglobin analysers in determining a standardised reference for low, normal and high haemoglobin values in blood and to compare the manual and automated methods of haemoglobin estimation. A total of 292 laboratories received three samples with low, normal and high haemoglobin concentrations for analysis, after which their results were evaluated for accuracy by comparing with the reference values. Accuracy of the analysers was evaluated using one-way analysis of variance while Coefficient of Variation was calculated as a measure of inter- method variability. Mean deviation from the expected mean of the references reflected the bias of each analyser. Overall 58.4 % (n=7/12), 17.6% (n=2/12) and 25% (4/12) gave accurate, underestimated and overestimated haemoglobin values respectively. Celltac, Humalyzer, Medonic, Mindray, Colourimeter, Hemocontrol and Sysmex produced results that were not significantly different from the reference values (P>0.05). Diaspect and Sahli underestimated while Hemocue, Urit and Mission overestimated Hb values (P<0.05). Automated methods were more precise than the manual methods with Coefficient of Variation for automated, semi-automated and manual methods being 7.08%, 7.04% and 34.26% respectively. With increasing reliance on the utilization of laboratory test outcomes for clinical decision- making, laboratories mustfrequently participate in External Quality Assessment in order to provide reliable results. Laboratories should embrace automation which gives more accurate and precise results.

Keywords: Haemoglobin, External Quality Assessment, Accuracy, Bias.

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Esther Wangui Mandania

Department of Medical Laboratory Sciences, Medical School, College of Health Sciences, Mount Kenya University