Mario Plebani. Laboratory errors: How to improve pre- and post-analytical phases? Biochemia Medica 2007;17(1):5-9. http://dx.doi.org/10.11613/BM.2007.001
Department of Laboratory Medicine, University Hospital of Padova and Center for Biomedical Research, Castelfranco Veneto, Italy
Corresponding author: mario [dot] plebani [at] unipd [dot] it
Patient safety agenda is gaining momentum in the health care systems of all developed countries. However, adverse event detection systems and initiatives to reduce error rates in medicine are in their infancy. Laboratory services play a crucial role in both individual and population-based healthcare, and clinical laboratories use many different methods to reduce errors, ensure patient safety, and improve quality including quality control procedures, quality assurance programs, accreditation of laboratories and certification of education programs. Considerable advances in analytical techniques, laboratory instrumentation, information technologies, automation and organization have granted an exceptional degree of analytical quality over the past 50 years. This, in turn, has resulted in a significant decrease in error rates, analytical error rates in particular. There is consolidated evidence that nowadays, most laboratory errors fall outside the analytical phase, and that pre- and post-analytical processes are more vulnerable to error than analytical processes (1-3). This expected distribution of errors should prompt clinical laboratories to focus their attention on pre-analytical and post-analytical processes in order to improve patient safety (4), as these phases seem to present the greatest potential for quality improvement once reliable strategies have been identified and properly applied.
However, some further considerations must be made. First, analytical quality is still a major issue. Recently reported data on analytical quality in clinical chemistry, evaluated on the σ scale, have demonstrated that values are generally less than 4, and in some cases, less than 3 σ, a benchmark for minimal acceptable quality (5). Similar, or even worse, data are available in other fields of laboratory medicine, in particular immunoassays, coagulation and molecular biology. Second, while laboratory activities have been traditionally classified as pre-, intra- and post-analytical, investigation of the beginning and the end of the total testing process (TTP) has revealed pre-pre-analytical and post-post-analytical phases (6). The first phase starts with test requesting, patient and specimen identification, blood drawing, sample collection and handling, and ends with the transportation of biological specimens to the laboratory. In the post-post-analytical phase, which is performed outside laboratory control, a clinician receives, reads and interprets results, and makes a decision on the basis of information from laboratory and other sources. The crucial question, therefore, is “have clinical laboratories to assume responsibility for the whole testing process, including appropriateness of test request and interpretation”? In ISO Technical Report 22367, a laboratory error is defined as “a defect occurring at any part of the laboratory cycle, from ordering tests to reporting results and appropriately interpreting and reacting in these” (7). This broad definition has several advantages and, in particular, it encourages a patient-centered evaluation of errors in laboratory medicine. According to these concepts, some practical considerations should be made in order to reduce errors in laboratory medicine and improve patient safety.
- While a significant decrease in laboratory errors, particularly analytical errors, has been achieved in last decades, laboratory services are not as safe as they should be and we should not become complacent. Technological solutions can make laboratory services safer, but they cannot be regarded as panacea. In particular, the new definition of “laboratory errors” encourages clinical laboratories to assume responsibility for the whole cycle of the testing process, including appropriateness in test requesting and interpretation. This responsibility, however, can be honored only through a closer liaison with clinicians and other health care professionals. Interdepartmental cooperation designed to improve the quality of test request, patient identification, specimen collection and handling, and data dissemination is the key to achieving the greatest possible quantitative reduction in laboratory errors (8).
- A more effective integration between automation and information management is the key to assuring a more sophisticated control of laboratory processes. Automation is responsible for sample assessment at the beginning of the process, optimized routing and scheduling, accurate and reliable measurements and reduction of errors that are due to active human factors and, e.g., repetitive and manual operations. For instance, the risk of errors in pre-analytical processes outside the laboratory has been reduced by the introduction of systems designed to manage the distribution of tubes, to attach a proper identification label, to produce auxiliary labels for sample collection, to convey and collect tubes into appropriate “patient kit”. Likewise, the introduction of pre-analytical workstations has dramatically reduced the number of errors in pre-analytical procedures performed in laboratory. Information management involves access processes, specimen tracking, data logging and reporting, documentation of quality control and validation of laboratory results. In particular, increasing interest has been shown in developing and evaluating autovalidation systems. The term “autovalidation” is used to define a “post-analytical computer-based intelligent system designed to simplify test interpretation” (9). These systems may allow laboratory specialists to perform rapid assessment and reporting of analytical data within the reference range and rapid assessment of abnormal data to generate diagnostic guidelines, thus identifying data trends that could become abnormal and detecting “hidden” medical conditions based on automatic interpretation of complex data. This, in turn, should translate into more accurate and reliable laboratory information. Therefore, an effective process control through integration between automation and information management is expected to significantly improve safety in the total testing process.
- Pre-pre-analytical steps seem to have the greatest possible potential for quality improvement. Proper patient and specimen identification remains a central issue. The widespread use of bar-coded wristbands is mandatory, but it does not eliminate the need for accurate verification of patient identity, more effective policies for specimen collection and well-trained staff. Shortage of skilled staff and overloaded phlebotomy facilities have amplified the potential for easily preventable errors. A recent survey on pre-analytical variability in a representative cohort of Italian laboratories has highlighted broad heterogeneity in several processes (10). The major issue appears to be the lack of agreement on specific protocols and reference guidelines between laboratories for the management of several critical processes. Compliance with the In ternational Standard for accreditation of medical laboratories, ISO 15189: 2003, requires a close control of specimen collection and handling (11). While some difficulties may arise when specimens are not collected and controlled by the laboratory, specific protocols and operating procedures (SOP) must be implemented and diffused, and their use and compliance must be continuously monitored.
- Post-post-analytical processes are another source of “gross” errors. A body of evidence demonstrates that laboratory information is only partially utilized. Several studies conducted in the last 30 years have demonstrated that clinicians either ignore or overlook 25 to 60% of abnormal routine test results (12). A more recent report showed that 45% of the results for urgent laboratory tests requested by the Emergency Department were never accessed (13). Results released by the laboratory may not contain all the information needed by a clinician, or laboratory report may contain information considered superfluous or irrelevant by a clinician. Available evidence points to an increasing awareness of the importance of communicating laboratory information, ensuring quality in laboratory reports, and providing interpretative comments and interpretive laboratory service (14).
- While quality indicators for the intra-analytical phase of laboratory activity have been well defined and their specifications internationally recognized, there is no consensus concerning types and acceptability limits for extra-analytical quality specifications. By comparing data on these indicators collected by different laboratories, a benchmark activity may be identified and realistic targets defined for quality in extra-analytical phases (15,16). If “zero defect” is the final goal for quality initiatives, the identification of valuable indicators for extra-analytical phases is a fundamental step in assessing and improving laboratory services (17).
Laboratory medicine is a highly dynamic sector of health care. The frequency and types of errors in laboratory medicine have changed for the better and are expected to change again in the future thanks to the constant development of more complex tests, great advances in instrument technology and ambitions for fully integrated laboratory information systems. While analytical quality is still a major issue, the greatest impact for overall improvement would be achieved by focusing on pre- and post-analytical processes in which most “gross” errors occur, the errors that can translate into adverse events or the risk of adverse events for patients. The total testing cycle is the unique framework to use for identifying and reducing errors in laboratory medicine, and we should never forget that laboratory professionals must be leaders in ensuring patient safety both inside and outside the walls of clinical laboratories.
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