Preanalyyttiset

Preanalyyttiset, or the pre-analytical phase, refers to all activities that occur before laboratory analysis and can influence test results. It includes patient preparation, specimen collection, handling, transport, storage, and processing. This phase is critical because many laboratory errors originate before the actual analysis, and its quality directly affects the reliability of test outcomes.

Key factors in the pre-analytical phase include both patient-related and specimen-related variables. Patient-related factors encompass age, sex, fasting state, medications, circadian rhythms, and recent physical activity. Specimen-related factors involve the type of specimen, collection technique, proper identification and labeling, the correct use of collection tubes with appropriate additives, and minimizing delays or mishandling. Operational steps such as ensuring the correct order of draw, reducing tourniquet time, secure sealing and labeling, timely transport, appropriate storage temperatures, and prompt processing (centrifugation and aliquoting) are essential. Common specimen quality issues include hemolysis from rough handling, lipemia from recent meals, icterus, clotting in plasma samples, and contamination.

Impact and quality control: Preanalytical errors can lead to erroneous results, misdiagnosis, inappropriate treatment, and the need for repeat testing. Measures to reduce these errors include standardized phlebotomy procedures, thorough staff training, clear patient preparation instructions, robust labeling with barcodes, reliable specimen transport and temperature control, and meticulous documentation of handling and timing. Adherence to international and national guidelines—such as CLSI standards and ISO 15189 accreditation requirements—along with hospital-specific standard operating procedures, supports consistent, high-quality pre-analytical practices.