Rilevazione, monitoraggio e trattamento di non conformità nella fase preanalitica: l’esperienza di un ospedale universitario metropolitano

Errors in laboratory testing process may have an adverse impact on patient care. The pre-analytical phase is responsible for ~70% of these errors. In this study we present our experience in assessing the frequency of pre-analytical errors in our university hospital, by monitoring their trend over time and comparing data with goals suggested in literature. The impact of corrective actions, if any, was also checked. A comprehensive retrospective analysis of pre-analytical nonconformities (NC) recorded through laboratory information system over a 5-year (2007-2011) time span was undertaken. Retrieved data were evaluated on a yearly basis, first for NC type and then for type of sample, laboratory section and hospital department involved. The relatively most frequent NC was the test request without the corresponding sample, accounting on average for 2.3% of all requested tests. Hemolysis occurred for in average 1.15% of all requested tests, affecting ~20,000 determinations per year, mostly interesting clinical wards taking care of critical patients, i.e. neonatology, oncology, and emergency department. Clotted and not sufficient samples showed a significant reduction over time after changing the analytical system measuring erythrocyte sedimentation rate and adopting more reliable tubes, easier to fill in and mix up. NC related to samples conveyed at wrong temperature were also relatively frequent. Our results show that recording, monitoring, and critically evaluating pre-analytical issues in laboratory testing process is mandatory for providing a good laboratory service, permitting to identify causes of NC and to apply corrective interventions that may help to reduce their incidence.