Rapid radioimmunoassay of circulating chromogranin A: in vitro stability, exploration of the neuroendocrine character of neoplasia, and assessment of the effects of organ failure.

Chromogranin A is a useful probe of neuroendocrine neoplasia in humans. Here we optimize a rapid, sensitive radioimmunoassay modification for detecting chromogranin A in humans and other species. The site of chromogranin A circulation is the acellular plasma; platelets contain no chromogranin A immunoreactivity.