Errors in Laboratory Medicine Pierangelo Bonini, 1,2* Mario Plebani, 3 Ferruccio Ceriotti, 2 and Francesca Rubboli 2 Background: The problem of medical errors has re- cently received a great deal of attention, which will probably increase. In this minireview, we focus on this issue in the fields of laboratory medicine and blood transfusion. Methods: We conducted several MEDLINE queries and searched the literature by hand. Searches were limited to the last 8 years to identify results that were not biased by obsolete technology. In addition, data on the fre- quency and type of preanalytical errors in our institu- tion were collected. Results: Our search revealed large heterogeneity in study designs and quality on this topic as well as relatively few available data and the lack of a shared definition of “laboratory error” (also referred to as “blunder”, “mistake”, “problem”, or “defect”). Despite these limitations, there was considerable concordance on the distribution of errors throughout the laboratory working process: most occurred in the pre- or postana- lytical phases, whereas a minority (13–32% according to the studies) occurred in the analytical portion. The reported frequency of errors was related to how they were identified: when a careful process analysis was performed, substantially more errors were discovered than when studies relied on complaints or report of near accidents. Conclusions: The large heterogeneity of literature on laboratory errors together with the prevalence of evi- dence that most errors occur in the preanalytical phase suggest the implementation of a more rigorous method- ology for error detection and classification and the adoption of proper technologies for error reduction. Clinical audits should be used as a tool to detect errors caused by organizational problems outside the laboratory. © 2002 American Association for Clinical Chemistry Measuring and improving laboratory-related patient out- comes require methods that relate the total quality of laboratory information to more effective patient manage- ment, including diagnosis, treatment of disease, clinical monitoring, and disease prevention. The improvement in analytical quality, documented through proficiency test- ing, should guarantee that the actual performances of clinical laboratories are suitable for improving a patient’s health. Furthermore, increased attention to patients’ needs is demonstrated by efforts to improve the quality of the entire service provided, e.g., reduction of the turn- around time (TAT). However, improvement of laboratory performance does not automatically indicate a reduction in the number of errors, both analytical and organiza- tional. Even certification or accreditation processes focus attention more on the general performance of the labora- tory than on events such as errors that, by their very nature, are considered exceptional. Moreover, the lack of a universally accepted definition of error and above all of “allowable error rate”, reduces the possibility of evaluat- ing the impact of laboratory error on patient outcomes. Although there is abundant scientific literature dealing with increased laboratory quality (mainly analytical), the literature on errors in laboratory medicine is scarce. One reason for this, in addition to the insufficient attention paid to the problem, is the practical difficulty in reporting and measuring the number of errors. In fact, there are several limitations in the study designs of reports dealing with the frequency and types of mistakes in the clinical laboratory. The first limitation is that most of the studies focus simply on analytical errors, which represent only a per- centage of the errors in the total testing process, which includes all pre-, intra-, and postanalytical phases. Other studies are based on methodologies, such as the split- specimen design, that are insensitive to total testing process problems that can occur before specimens are collected and after results are obtained by the analytical process (1, 2). 1 Universita ` Vita-Salute San Raffaele, Cattedra di Biochimica Clinica, Via Olgettina 58, 20132 Milan, Italy. 2 Istituto Scientifico H. S. Raffaele, Servizio Integrato di Medicina di Laboratorio, Via Olgettina 60, 20132 Milan, Italy. 3 Servizio di Medicina di Laboratorio, Azienda Ospedaliera di Padova, Via Giustiniani 2, 35100 Padova, Italy. *Author for correspondence. Fax 39-02-2643-2640; e-mail bonini. pierangelo@hsr.it. Received July 20, 2001; accepted February 12, 2002. Clinical Chemistry 48:5 691– 698 (2002) Minireview 691