ACTH-RIA: Comparison of commercially available antisera and standards

The results demonstrate great differences in sensitivity between the commercial antisera studied. In view of the physiologically low plasma levels of ACTH determination of this peptide using antisera B, C or D is only feasible if ACTH extraction from larger plasma samples precede the final RIA. The great range of sensitivity resulting from the use of different standards with the same antiserum illustrates well the problem of standardization inherent to most protein and peptide RIAs. It strongly indicates the necessity of an uniform standard, especially if external quality control experiments will be put forward. (orig./AJ)