Standardization in Peptide Hormone Immunoassays: Principle and Practice

This general paper starts with principles that are obvious to those who already know about biological standardization. I apologize for that; but I think these are honourable principles that should be kept in mind by those using immunoassay methods and application. Medicine, and especially endocrinology, needs accurate measurements; this requires the discipline of stan-dardization, which is a way of making assays valid and accurate so that results can be compared from labora-tory to laboratory and from time to time. I shall outline the principles on which comparative assays depend, the difficulties in following them in the rigorous way de-manded for immunoassays, and some measures to cope with these difficulties. I shall discuss the service of in-ternational standards and the present urgent need for national ones, and urge to your attention the advice on this whole subject given by the World Health Organi-zation (WHO). Standardization should be achieved by following a discipline based on certain principles, not by imposing the use of a prescribed assay procedure. Immunoassays are comparative assays, the validity of which depends on certain fundamental assumptions. These are basic and have long been used in biological sciences such as physiology and pharmacology; they were later described by Jerne and Wood in 1949 (1), and their application in binding assays has been discussed (2). The first assumption is that the substance in the sample assayed is identical to that in the standard, or at least similar to it to the extent that it behaves in the test system as if it were a dilution of the standard. National Institute for Biological Standards and Control, Holly Hill, Hampstead, London NW3 6RB, England. This paper is based on a presentation at the first Pine Mountain Conference, sponsored by the AACC. The topic of this Conferenc