“…Whilst these were by no means the first such medicines, Ehrlich was the first to calibrate the purity of the preparations of these substances by bio-assay against an arbitrary standard kept at low temperature (Ehrlich et al 1894;Ehrlich 1910). In the 1960's the need for reliable quality control of clinical chemistry determinations had been highlighted in the USA and England following the introduction of the first reliable automated analytical systems, the Technicon Auto-Analyzer Whiteheads work at the University of Birmingham led to the introduction of routine inter-laboratory performance testing schemes and the regular use of thoroughly validated reference materials (Radin 1967;Meinke 1971;Booth et al 1974;Whitehead 1976). These standards were increased in number after the discovery of vitamins and sex hormones in the 1930's (e.g.…”