Artifacts in the radioimmunoassay of peptide hormones in gastric and duodenal secretions.

Observations of apparently high concentrations of gastrin and insulin in gastric and duodenal secretions as determined by radioimmunoassay may arise from artifacts caused by proteolytic enzymes. The double-antibody and charcoal separation techniques as commonly employed fail to recognize extensive proteolytic damage to labeled antigen and to antibody.