Estimation of uncertainty measurement - A prerequisite of ISO1589 accreditation for clinical laboratories.

OBJECTIVE To estimate relative expanded uncertainty measurement of routine clinical chemistry analytes for international organisation for standardisation 15189 accreditation. METHODS This cross-sectional study was conducted at Dow International Medical College, Karachi, from September 2013 to May 2014. During the process of international organisation for standardisation 15189 accreditation, measurement uncertainty was estimated for 13 clinical chemistry analytes using top-down approach. Relative combined uncertainty of each analyte was calculated by combining uncertainties of imprecision, bias and calibrators. Results of estimated imprecision, bias and expanded uncertainties were observed for allowable imprecision, bias and total analytical error for the respective analyte.. RESULTS Uncertainties of imprecision were found within acceptable limits for all analytes except total protein (2.4% vs. 1.3%). Uncertainties of bias of all analytes were found within allowable limits. Relative expended uncertainties of all analytes were found acceptable except total protein (4.7%vs 3.63%). CONCLUSIONS The approach used to estimate the measurement uncertainty may be found simple and feasible by clinical laboratories interested in getting the relevant accreditation.