International Lp(a) standardization.
Two international surveys for Lp(a) measurements were organized from 1989 to 1991. The results of the first survey led to the conclusion that the lack of a common primary standard was the main cause of the large inter-laboratory variation observed. No major effects of techniques or antisera were observed. The same findings were confirmed during the second survey, which was extended to include more samples and a larger number of participants. During the second survey, no consistent effect due to freezing or lyophilization could be demonstrated, although there was a trend towards lower Lp(a) values in lyophilized samples. The inter- and intra-laboratory coefficients of variation did not vary significantly for the different Lp(a) phenotypes, and variability was comparable for lyophilized, liquid and frozen materials. Large intra-assay coefficients of variation were observed during both surveys. Results obtained in different laboratories using the same commercial reagents and standards also showed a large variation. These initial results demonstrate that the lack of a primary standard and poor assay precision are the main factors responsible for the high inter-laboratory variation observed during these surveys.
Labeur
C
C
Innogenetics N.V., Ghent, Belgium.
Rosseneu
M
M
Henderson
O
O
D000704:Analysis of Variance; D001774:Blood Chemical Analysis / Q000379:methods / Q000592:standards* / Q000706:statistics & numerical data; D003625:Data Collection; D006801:Humans; D007391:International Cooperation; D007753:Laboratories / Q000592:standards; D017270:Lipoprotein(a) / Q000097:blood / Q000592:standards*; D012015:Reference Standards
D017270:Lipoprotein(a)