Abstract:

Objective To evaluate the uncertainty of Doumas total bilirubin（TB） reference measurement procedure by Guide to the Expression of Uncertainty in Measurement（GUM）uncertainty framework（GUF）. Methods The sample of the International Federation of Clinical Chemistry and Laboratory Medicine（IFCC） External Quality Assessment Scheme for Reference Laboratories in Laboratory Medicine（RELA） was determined by Doumas TB reference measurement procedure of the Joint Committee for Traceability in Laboratory Medicine（JCTLM）. The sources of each uncertainty component in the whole procedure were identified. The evaluation of uncertainty components was processed,and a relative combined uncertainty was calculated. Finally,standard uncertainty and expanded uncertainty were given. Results The concentrations of TB of 2014 RELA-A and RELA-B samples were 67.33 and 31.99 μmol/L. The relative combined standard uncertainties were 1.57% and 1.61%. The standard uncertainties were 1.06 and 0.52 μmol/L. The 95% confidence interval was taken,the coverage factor（k）was 1.96,so the expanded uncertainties were 2.07 and 1.01 μmol/L. Conclusions The uncertainty of TB by reference measurement procedure by GUF can meet the requirements of clinical laboratory.

Key words: Total bilirubin, Serum, Reference measurement procedure, Measurement uncertainty evaluation, Guide to the Expression of Uncertainty in Measurement uncertainty framework