preanalyyttinen

Preanalyyttinen, or preanalytical, refers to the phase in laboratory testing that occurs before the actual analytical measurement of a specimen. It covers activities from the test order and patient identification through specimen collection, handling, transport, processing, and initial preparation such as centrifugation and aliquoting, as well as storage conditions and the maintenance of the chain of custody.

The preanalytical phase includes patient preparation and proper specimen collection methods, correct labeling and identification, and ensuring specimen quality. It also involves appropriate specimen types and tubes, order of draw when multiple tests are collected, and the management of factors that can affect results, such as fasting status, recent medications, and diurnal variation. Sample quality issues such as hemolysis, lipemia, icterus, insufficient volume, contamination, or delays in transport are typical concerns in this phase.

Errors in the preanalytical phase are a major source of total laboratory errors and can lead to incorrect results, misdiagnosis, or inappropriate treatment. To minimize risk, laboratories implement standardized operating procedures, staff training, clear specimen collection protocols, proper labeling and triage of samples, timely transport, and appropriate storage. Quality management often draws on data from error tracking, root cause analyses, and continuous improvement initiatives.

Standards and guidelines from organizations such as ISO 15189 and CLSI guide preanalytical practices and help harmonize procedures across laboratories. Emphasis is placed on patient safety, traceability of specimens, and documentation to ensure reliability and accuracy of laboratory testing from the moment a test is ordered.