Rapid and specific RIA of serum estrone sulfate with selective solid phase extraction.

The methods commonly used to evaluate conjugated steroids require hydrolysis and chromatographic purification. To avoid these steps, a simple method involving selective solid phase extraction and RIA using a highly specific antiserum for estrone sulfate (E1S) has been evolved. A Bond-Elut C2 cartridge was used for solid phase extraction of estrone (E1) and E1S; recoveries were 80 and 90% respectively. The intra- and inter assay precision of the assay at 3 serum levels, were 6.5, 10.4 and 4.4 and 12.7, 13.9 and 7.4% respectively. Accuracy, tested by linearity and recovery tests, was acceptable. A good correlation exists between a conventional enzymatic method and the proposed method. The latter is less time consuming and more reliable, thus providing a rapid assay to evaluate E1 and E1S in the same serum sample.