Recommendations for the detection and management of unsuitable samples in clinical laboratories

A large body of evidence supports that quality improvement efforts tailored to the analytical phase only, are less likely to generate further clinical and economical progresses. Actually, most diagnostic errors made within the laboratory diagnostics emerge in the extra-analytical domains of testing, especially within the preanalytical phase. It is now clear that the underlying causes are most frequently due to system errors or to the implementation of poorly standardized procedures for collection, handling, transportation, preparation and storage of biospecimens. Some of these problems could generate a number of issues related to the quality of clinical samples, ending up with the reception by the laboratory of unsuitable samples. The identification and the management of unsuitable samples represent thus unavoidable practices in clinical laboratories to guarantee the quality of test results throughout the total testing process. Due to the ongoing evolution of the in vitro diagnostic market and the availability of new evidence, this paper provides a revision of the national recommendations issued by the Italian Society of Clinical Biochemistry and Clinical Molecular Biology in 2007 for detection and practical management of unsuitable specimens in clinical laboratories.