[Characteristics of guinea pig anti-bovine parathormone antiserum used in radioimmunologic determination of human parathormone].

The cross-reaction for hPTH radioimmunoassay and the multiple forms of hPTH circulating, pose several problems in interpreting results. This communication reports a sensitive radioimmunoassay for hPTH utilising a guineapig antiserum which is reactive with the amino-terminal region retaining biological activity, and which cross-reacts completely with hPTH, indicating levels of hPTH expressed as bovine PTH equivalent that would be correct.