Affiliation:
1. Department of Internal Medicine II—Cardiology, University of Ulm Medical Center, Ulm, Germany
2. Ludwig-Maximilians-University Munich, Department of Statistics, Munich, Germany
3. National Research Center for Environment and Health, Institute of Epidemiology, Neuherberg, Germany
Abstract
Abstract
Background: Of the numerous emerging biomarkers for coronary heart disease (CHD), lipoprotein-associated phospholipase A2 (Lp-PLA2), an enzyme involved in lipid metabolism and inflammatory pathways, seems to be a promising candidate. Implementation of Lp-PLA2 measurement into clinical practice, however, requires data on the reliability of such measurements.
Methods: We measured Lp-PLA2 concentrations by ELISA in blood samples drawn from 200 post–myocardial infarction patients (39–76 years) at 6 monthly intervals between May 2003 and February 2004, for a total of 1143 samples. We estimated analytical, within-individual, and between-individual variation, the critical difference, and the intraclass correlation coefficient of reliability (ICC) to assess the reliability of serial Lp-PLA2 measurements.
Results: The mean (SD) plasma Lp-PLA2 concentration for the study participants was 188.7 (41.8) μg/L, with no significant difference between men and women. The analytical CV for Lp-PLA2 was 4.4%, the within-individual biological CV was 15%, and the between-individual CV was 22%. The ICC was 0.66. An important part of the total variation in plasma Lp-PLA2 concentration was explained by the between-individual variation (as a percentage of the total variance, 66.1%), whereas the within-individual variance was 31.3%. The analytical variance was as low as 2.6%.
Conclusions: Between-individual variation in Lp-PLA2 concentration was substantially greater than within-individual variation. In general, our data demonstrate considerable stability and good reproducibility of serial Lp-PLA2 measurements, results that compared favorably with those for the more commonly measured lipid markers.
Publisher
Oxford University Press (OUP)
Subject
Biochemistry (medical),Clinical Biochemistry
Cited by
18 articles.
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