Proficiency testing of total serum cholesterol assay by the ATAC 8000® random access chemistry auto analyzer at the Komfo Anokye teaching hospital

Abstract

Cardiovascular disease has become a leading cause of death with hypercholestrolaemia being one of the most important and implicated modifiable risk factor in both developed and developing countries. Analysis of cholesterol is thus important and many analytical techniques have been de-veloped. Different methods for determining total cholesterol can produce varying laboratory results, thus illustrating the importance of quality control. The present study, therefore, aims at comparing the ATAC 8000 Random Access Chemistry Autoanalyzer used at the KATH, the manual enzymatic method and the WHO recommended manual method with reference to total cholesterol assay. A 20 day replication run was conducted utilizing stabilized human control serum. Methods comparison was then performed on 90 patient samples using the ATAC 8000 autoanalyzer adopted method for estimating cholesterol (enzymatic end point method) as the test method, the manual enzymatic end point method and the WHO recommended Liebermann-Burchard method as comparative methods, to analyse total serum cholesterol. ATAC 8000 gave the lowest CV of 3.0% and total error (TE) of 6.5%, followed by the Liebermann-Burchard method (CV of 4.6%; TE of 9.0%) and the manual enzymatic method (CV of 7.0%; TE of 13.7%). The recommended CV ranges from 3-5% with TE being ≤ 8.9%. The autoanalyzer consistently generated results that were higher than the other methods with good precision and accuracy. Based on the capability index (Cp), ATAC 8000 had the highest Cp of 2.5 followed by Liebermann-Burchard method with a Cp of 1.8. The higher the Cp, the lower the risk of jumping the tolerance limits and therefore the higher the quality. The Bland-Altman analysis showed good agreement between the ATAC 8000 and other methods. Total analytical error, capability index and CV produced by the method adapted for cholesterol estima-tion by ATAC 8000 Random Access Chemistry autoanalyzer is acceptable since all are within the recommended and set ranges for total cholesterol.

Keywords: ATAC 8000, Liebermann-Burchard Method, Enzymatic endpoint method, Total Cholesterol

Journal of Medical and Biomedical Sciences (2013) 2(1), 22-29