Critical pre-examination variables in the hemostasis laboratory and their quality indicators

The total testing process comprises a number of phases of laboratory testing, which can be broadly considered as comprising pre-examination, examination and post-examination activities. Although each phase is crucial to providing accurate and meaningful laboratory results, the pre-examination phase of testing is where most laboratory errors currently occur, and thus requires special attention. The activities in this phase include sample collection, handling, transportation, processing and storage, which are frequently outside the control of the laboratory performing the tests. Samples for hemostasis testing are particularly vulnerable to pre-analytical variables, which may ultimately lead to inappropriate test results. We outline here several strategies to mitigate potential problems in the pre-examination phase. We also recommend the implementation of several processes to reduce errors.