Lack of consistency between two commercial ELISAs and against an in-house ELISA for the detection of CD36 in human plasma.

Background: CD36 is a widely expressed cell surface receptor, that among other ligands binds lipoproteins, and its function has been implicated in many of the complications belonging to the metabolic syndrome. We have previously identified a circulating form of CD36 and established an in-house ELISA assay for measurement of CD36 in plasma. Plasma CD36 was elevated in insulin resistant obese and diabetic patients, and in patients with unstable atherosclerotic plaques. The objective of this study was to compare two new commercial CD36 ELISA assays and our in-house ELISA assay. Methods: CD36 was measured in 30 plasma samples from 10 individuals by the in-house and the two commercial assays (Cusabio Biotech and Adipobioscience). Results: Our results demonstrate that there is an absolute incongruity between the three assays. The incongruity could not be explained by different pre-analytical procedures in assay protocols. Conclusions: The lack of correlation indicates that measurement of CD36 levels in plasma is not trivial. The two commercial assays are not appropriate for CD36 detection in plasma and it seems unlikely that the established pathophysiological association with elevated plasma CD36 can be reproduced.