Biologicals: test procedures available to assess components and products, with limitations

Contamination with a pathogen, residual live organisms in inactivated products, and a lack of safety of live products may be considered to constitute the greatest risks associated with the use and the international movement of biological products. Although tests are conducted to monitor the risks, the limitations of such tests must be recognised and steps should always be taken to minimise and, as far as possible, avoid the risk. Tests must be suitably sensitive and specific for their function, but they must also be practical and reproducible. Studies on the sensitivity of tests provide a measure of their limitations. The author describes points to consider for the assessment of the suitability of different test methods. Emphasis is placed on tests for parameters associated with risk, such as extraneous agent testing. Examples of such analyses are discussed. There is a need for an exchange of information and a scientific debate on such issues if international acceptance of test methods and harmonization of requirements are to be achieved.