Recalibration of biochemistry measurements in a multinational cohort study: LIFE course study in CARdiovascular disease Epidemiology (LIFECARE)

Abstract Background Various cardiovascular biomarkers are used to assess and compare the risk of cardiovascular diseases across populations. However, artefactual variations due to the use of different laboratories may make these comparisons invalid. This work describes the inter-laboratory variations in a multi-country cohort, LIFECARE, and the use of recalibration to a reference laboratory to minimise this variability. Methods LIFECARE is a cohort of 10,479 participants recruited from Indonesia, Malaysia, Philippines and Thailand between 2008 and 2011, with blood samples analysed at country-specific laboratories(n=4). Thailand was the designated reference laboratory. The measurements from each laboratory were compared against the reference laboratory using a common set of samples analysed at all laboratories, using the MethComp package in R. Laboratory values for cohort participants were recalibrated using the equation generated by the package, if large, statistically significant differences were observed during the comparison. Results Glucose, total cholesterol, HDL cholesterol, LDL cholesterol and triglyceride measurements were reported for all four countries. Cholesterol and HDL from all laboratories required recalibration while glucose did not. Recalibration altered the proportions of the population at risk substantially, with prevalence of high cholesterol changing from 56.3% to 75.0% in Malaysia, 52.1% to 37.5% in Indonesia and 31.3% to 22.7% in Philippines. Prevalence of low HDL was similarly altered. Conclusion There was significant variation in serum lipid levels measured by different laboratories, leading to variations in estimates of population at risk. Recalibration to a reference laboratory can overcome this variability and facilitate meaningful comparisons of laboratory data across countries.