Serum levels of dehydroepiandrosterone sulfate as determined by commercial kits and reagents

We measured serum dehydroepiandrosterone sulfate (DHEA-S) levels by nine different radioimmunoassay (RIA) methods. Although each method was adequate for determining the amount of authentic DHEA-S, there were marked differences observed between the methods when serum samples were tested. Further, the pattern of these differences varied in different clinical situations. We suggest that the differences in the apparent DHEA-S content resulted from the presence of structurally related compounds which differ in their cross-reactivity in the different RIAs. One of these cross-reacting materials may be a functional androgen.