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1. What is diagnostic errors？

Diagnostic errors, according to the Technical Specification (ISO/TS 22367), are defined as failure of planned action to be completed as intended, or use a wrong plan to achieve an aim, occurring at any part of the laboratory cycle, from ordering examinations to reporting results and appropriately interpreting and reacting to them ^[1].
The management of diagnostic errors has evolved from a focus on analytical errors within the laboratory to a more comprehensive approach that includes pre- and post-analytical phases (total testing process, TTP). This shift began with the Institute of Medicine's (IOM) report, "To Err is Human," which brought patient safety to the forefront and emphasize “patient-centred care” ^[2].
However, laboratory errors are often insidious and difficult to pinpoint in terms of time and place ^[3]. Firstly, there is a time delay between laboratory tests, physician actions, and patient outcomes. Secondly, only the analytical phase is controlled by the laboratory, while the pre- and post-analytic phases involve multiple providers. Additionally, physicians often do not recognize laboratory errors as significant sources of adverse events and may be unaware that most errors occur in the pre- and post-analytic phases. Furthermore, laboratory testing is expanding to include point-of-care and self-monitoring, adding complexity to the process.
Without proper management, diagnostic errors can have severe consequences for patient safety, leading to inappropriate care and adverse events. They also contribute significantly to the economic burden on the healthcare system.

Table-1 Development of Diagnostic Errors Management ^[1]

2. Types of diagnostic errors

2.1 Pre-, intra-, and post- analytical errors
As in the original classification, the diagnostic process is divided into pre-analytic, analytic, and post-analytic phases ^[4]. Pre-analytical errors are most common and can occur during patient assessment, test ordering, specimen collection, and transport. Analytical errors involve issues with test performance, including equipment malfunction and sample contamination. Post-analytical errors happen during the reporting and interpretation of results, including failure to communicate critical values and improper data entry. Further study showed that pre- and post- analytical phase could be more accurately divided into pre-pre- and post-post- analytical phase ^[3]. They are the initial and final steps of the laboratory testing process, notably test requesting and reaction to results, are more error-prone and critical than other phases, contributing significantly to potential adverse outcomes for patients.

Table-2 Types and Rates of Error in the Diagnostic Process ^[5]

2.2 Central Lab V.S. POCT
Central lab errors typically occur within a controlled environment and involve complex testing procedures. POCT errors, which happen at or near the patients, may be influenced by factors such as operator training and environmental conditions. In theory, POCT is designed to eliminate some of the problematic steps in the testing process, such as specimen transport and result distributions ^[3,6]. However, POCT introduces new challenges in operator competence and adherence to procedures, potentially amplifying the clinical impact of errors and leading to adverse events for patients. For example, significant errors were found in data transcription and incomplete reporting using portable glucose meters in hospitals^[3].
Overall, while POCT has spread impressively and is driven by the perception that it is simple and provides fast results, it does not inherently reduce errors and risks in all steps of the testing process.

3. How to prevent these errors?

3.1 Systematic Improvements
Recognizing systemic factors that contribute to errors is crucial because many mistakes result from issues within the overall system rather than individual negligence. By focusing on improving working conditions and implementing defense layers and safeguards, laboratories can mitigate these errors. Tools such as Failure Mode and Effects Analysis (FMEA), Hazard Analysis and Critical Control Points (HACCP), and Hazard and Operability Study (HAZOP) are instrumental in identifying potential weaknesses and risks within the lab processes ^[3]. The goal is to create a safer and more reliable working environment that reduces the likelihood of errors.
Additionally, developing and implementing standardized diagnostic pathways or algorithms helps streamline testing processes, ensuring that each step is clearly defined and reducing the chances of inappropriate test selection. This leads to more accurate diagnoses and better patient outcomes ^[7].

3.2 Automation and Technology Support
Human errors are a significant source of mistakes in lab testing. Implementing automated systems like computerized physician order entry (CPOE) helps minimize transcription errors by digitizing the ordering process ^[7]. Barcoding systems for patient and sample identification ensure that specimens are correctly matched to patients, reducing identification errors. Automated result validation systems can quickly and accurately verify test results, further reducing the chance of human error. Additionally, designing devices and procedures to make safe operations the easiest to follow is critical. Incorporating forcing functions and lockouts can prevent foreseeable violations, ensuring that even if a mistake is made, it does not lead to significant harm. This proactive approach enhances the overall safety and reliability of lab operations ^[8].

3.3 Education and Feedback
Continuous education and feedback are vital for maintaining high standards in laboratory practices. Providing educational interventions and regular feedback to clinicians and laboratory staff helps improve their knowledge and adherence to best practices, such as proper sample collection and result interpretation. Regular training ensures that staff are up-to-date with the latest protocols and techniques. Conducting proficiency tests for operators and reviewing their results allows supervisors to assess the operators’ knowledge of error prevention and detection. This ongoing evaluation helps identify areas where further training is needed and reinforces a culture of continuous improvement. Enhanced education and feedback lead to a more knowledgeable and competent workforce, reducing the likelihood of errors ^[7].

3.4 Monitoring and Management
Effective monitoring and management are essential for maintaining quality and preventing errors in laboratory testing. Forming diagnostic management teams that include laboratory specialists and clinicians fosters better communication and collaboration ^[7]. These teams work together to improve the appropriateness of test selection, ensure accurate interpretation, and take timely actions based on test results. Monitoring and benchmarking quality indicators (QIs) helps identify error-prone areas and track the effectiveness of improvement strategies. By regularly reviewing QIs, labs can pinpoint specific issues and measure progress over time. This approach ensures that quality improvement efforts are data-driven and targeted, leading to more effective and sustainable improvements in lab performance ^[7].

Reference
[1] Plebani, Mario. "Diagnostic errors and laboratory medicine–causes and strategies." Ejifcc 26.1 (2015): 7.
[2] Donaldson, Molla S., Janet M. Corrigan, and Linda T. Kohn, eds. "To err is human: building a safer health system." (2000).
[3] Plebani, Mario. "The detection and prevention of errors in laboratory medicine." Annals of clinical biochemistry 47.2 (2010): 101-110.
[4] Hammerling, Julie A. "A review of medical errors in laboratory diagnostics and where we are today." Laboratory medicine 43.2 (2012): 41-44.
[5] Plebani, Mario. "Exploring the iceberg of errors in laboratory medicine." Clinica chimica acta 404.1 (2009): 16-23.
[6] Plebani, Mario. "Does POCT reduce the risk of error in laboratory testing?." Clinica chimica acta 404.1 (2009): 59-64.
[7] Mrazek, Cornelia, et al. "Errors within the total laboratory testing process, from test selection to medical decision-making–A review of causes, consequences, surveillance and solutions." Biochemia medica 30.2 (2020): 215-233.
[8] Meier, Frederick A., and Bruce A. Jones. "Point-of-care testing error: sources and amplifiers, taxonomy, prevention strategies, and detection monitors." Archives of Pathology and Laboratory Medicine 129.10 (2005): 1262-1267.

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