Objective: Errors in clinical laboratories have an important effect on safety and care of patients. Thus, causes of specimen rejections should be identified and corrected to guarentee quality results. The objectives of this study were to identify and classify the causes of biological specimen rejections, to determine the specimen rejection rates for improvements at this stage, and contribute data to the literature.

Materials and Methods: In this retrospective study, data on rejected biological specimens in the laboratory information system (LIS) of Kayseri Training and Research Hospital (KEAH) from July 2013 and July 2014 were analyzed. Specimen rejection rates according to the causes of sample rejections and collection area were determined.

Results: In total, 1.648.462 biological specimens were received during the period and 8.253 (0.5%) specimens were rejected based on our laboratory rejection criteria. Specimen rejection rates were %0.6 and %0.3 for hematological and biochemical tests respectively. Clotting of specimens was the most frequent reason for rejection (65.42% of total rejections), followed by incomplete volume (19.03% of total rejections) for hematological tests. Hemolytic specimen was the most frequent reason for rejection (78.45% of total rejections), followed by incomplete volume (6.90% of total rejections) for biochemical tests.

Conclusions: The common causes of specimen rejection in our study included clotted samples, hemolytic samples and incomplete volume for hematological and biochemical tests. Repetitive training programs about preanalytical errors were planned for phlebotomy staff and laboratory technicians. In this way, labor and financial loss due to preanalytical errors can be prevented.