Testosterone radioimmunoassay: rapid extraction technique for steroids based on kieselguhr mini-columns

A technique for the rapid extraction of steroids from serum prior to their radioimmunoassay is described. The technique is based on the use of mini-columns filled with kieselguhr (Extrelut; Merck). The columns provide a means of achieving a rapid and precise extraction without the problem of emulsion formation and without the necessity to accurately measure organic solvent volumes. The technique is inexpensive, time saving and at least as precise as most conventionally extracted steroid assays. The results achieved correlate well with those of a conventionally extracted assay.