Decision Rules for Measurement Results in Testing and Medical Laboratories with ISO Accreditation Requirements

The work of the laboratories does not end with the measurement or examination results. However, there are significant differences between medical laboratories and testing laboratories in how they handle results. Comparing the two approaches, useful insights can be gained regarding both metrological concepts and the practice of activities. Testing laboratories have always been confronted with the interpretation of measurement results to make decisions, in relation to the intended users of test reports, based on threshold values and measurement uncertainty. In medical laboratories, the approach is quite different. For ISO 15189 accreditation requirements recipients of test results are given interpretive criteria provided by reference intervals, decision limits and differences from previous results. Constantly improving guidelines are available for this. However, critical points emerge that laboratories must take into account, involving both formal and content aspects. Some of these critical issues have been highlighted in the official SIPMeL recommendations. The laboratories can choose different criteria for interpreting test results: either relying primarily on measurement uncertainty or aligning as closely as possible with medical decision-making.