Résumé:
The pre-analytical phase (PAP) represents a critical stage in the process of biological testing, accounting for over 60% of laboratory errors. It encompasses all procedures performed before the analytical stage, including medical prescription, patient preparation, specimen collection, transport, and storage. The aim of this study is to assess the impact of the PAP on the reliability of biological test results. The first part of the work provides a review of the main sources of pre-analytical errors and the various factors that may affect analytical quality. The second part presents an experimental study conducted at the Public Hospital of Aïn Tédelès (Mostaganem) between February and April 2025, focusing on blood glucose measurements in 27 patients. Three parameters were investigated: fasting duration (6 vs 12 hours), storage conditions (optimal vs inadequate), and collection methods. The results showed a significant decrease in blood glucose levels after 12 hours of fasting, as well as markedly lower glucose values in inadequately stored samples, likely due to post-collection glycolysis. In addition, variations were observed depending on the sampling techniques used. A survey conducted among laboratory staff revealed shortcomings in the application of best practices, particularly in terms of hygiene and sample homogenisation. These findings highlight the major influence of the pre-analytical phase on the reliability of laboratory analyses and underline the need to strengthen procedures, improve continuous training, and raise awareness among healthcare personnel regarding pre-analytical requirements.
