Abstract
A workshop on ICSA determination was organized to study whether ICSA data from different institutions were consistent. or not. Forty-two serum samples were distributed to 11 institutions where ICSA of human samples is frequently assayed. The majority of samples were asseyed by at least five different institutions. The results for each sample from the different institutions were highly inconsistent. Relatively similar results were obtained in the institutions using cultured pancreatic endocrine cells as an antigen. Species differences in pancreatic endocrine cells (antigen) seemed not to have any effect on the results. Small differences in methods and techniques between institutions may have had a large effect on the results. We are not able to solve the problem of this inconsistency at present. However, during the course of the discussion, many of us agreed that easily obtainable cultured pancreatic endocrine cells (i. e., RINr cells) might be a preferable antigen for ICSA determination in view of the inter-institutional differences.
