Reference values of apolipoproteins A1 and B. Contribution of international standardization. Travail collaboratif entre la SFBC, l'Arcol et le SFRL]

The utilization of two WHO reference materials, liquid and lyophilized, permitted international standardization of apolipoprotein measurements. We report here the results of a collaborative study between Arcol, SFBC and SFRL in order to establish reference ranges for apo A1 and B on nine standardized systems. A population of 1027 men and women supposed healthy, 4 to 60 year old, have been selected in two Centers for Preventive Medicine. The serum samples were aliquoted frozen at -20 degrees C the day of sampling and analysed by the manufacturers with IFCC standardized calibrants. A specific quality control was performed using a frozen pool of sera. For apo A1, the centile 2.5 of the reference population varies from 1.04 to 1.16 g/l. The range values for the centile 97.5 varies from 1.87 to 2.24 g/l. For apoB, the centile 2.5 varies from 0.43 to 0.57 g/l, and the centile 97.5 from 1.30 to 1.39 g/l. Only one system has a problem of dispersion with an upper limit equal to 1.20 g/l. These results improve that international standardization allowed actually a good comparability of the results, especially for apoB.