General principles, problems and interpretation in the radioimmunoassay of calcitonin.

Although radioimmunoassay (RIA) methods for calcitonin (CT) have been available for ten years, there remain problems in achieving high sensitivity, controlling plasma and other protein artifacts, and interpreting results in light of circulating CT heterogeneity and tumor products having CT-like immunoreactivity. The development of sensitive radioimmunoassays meeting these criteria remains challenging. We will review some of the approaches to these problems.