Validation, standardization and control of ELISA techniques for the diagnosis of infectious diseases in veterinary medicine

The decision to use a new enzyme linked immunosorbent assay (ELISA) technique to diagnose infectious diseases in veterinary medicine must be based on careful validation and standardization of the test to ensure a high level of accuracy according to defined criteria. In particular, laboratories performing diagnostic tests related to control, surveillance or eradication programmes need to take care in producing accurate and precise test results in their daily routine. To ensure this, laboratories should have an acceptable level of organization and management that provides sufficient guarantee of producing reliable test results. Measures should include the performance of a well documented internal quality control (QC) programme in which internal control samples are calibrated against national or international reference standards where possible. The internal QC programme should be focused on test precision (random and systemic errors) and, if possible, also on test accuracy (correctness of test results). It is of importance that reference or specialized laboratories make primary or secondary reference standard samples available to diagnostic laboratories in order to enable careful calibration of internal control samples. An objective of monitoring test accuracy is the participation in (inter)national external QC programmes organized by independent specialized and/or authorized reference laboratories. When possible, diagnostic laboratories should participate in such external QC programmes. Some aspects of the QC programme as used in veterinary immune diagnostic laboratories in the Netherlands are described. (author)