Do We Know Why We Make Errors in Morphological Diagnosis? An Analysis of Approach and Decision-Making in Haematological Morphology

• Morphological assessment of blood films at all levels requires complex problem-solving skills
• In all cases morphologists apply heuristic approaches; these differ according to case complexity
• Biases related to heuristics are evident in many errors, avoiding them requires specific strategiesWhen a large group of healthcare professionals examined the same blood films using a digital “virtual microscope”, we found that individuals supported their knowledge-based decisions using a range of additional techniques to reinforce or simplify their analyses. These skills are similar to those used in many different areas of human decision-making and support rapid and accurate choices. However, the approaches may also lead to unrecognised bias (as we have found in our study). To reduce errors in diagnosis, we suggest that training and support systems should identify and reinforce these choice-skills, while seeking to identify and avoid associated bias.

SummaryBackgroundThe laboratory interpretation of blood film morphology is frequently a rapid, accurate, and cost-effective final-stage of blood count analysis. However, the interpretation of findings often rests with a single individual, and errors can carry significant impact. Cell identification and classification skills are well supported by existing resources, but the contribution and importance of other skills are less well understood.MethodsThe UK external quality assurance group in haematology (UK NEQAS(H)) runs a Continued Professional Development scheme where large digital-images of abnormal blood smears are presented using a web-based virtual microscope. Each case is answered by more than 800 individuals. Morphological feature selection and prioritisation, as well as diagnosis and proposed action, are recorded. We analysed the responses of participants, aiming to identify successful strategies as well as sources of error.FindingsThe approach to assessment by participants depended on the affected cell type, case complexity or skills of the morphologist. For cases with few morphological abnormalities, we found that accurate cell identification and classification were the principle requirements for success. For more complex films however, feature recognition and prioritisation had primary importance. Additionally however, we found that participants employed a range of heuristic techniques to support their assessment, leading to associated bias and error.InterpretationA wide range of skills together allow successful morphological assessment and the complexity of this process is not always understood or recognised. Heuristic techniques are widely employed to support or reinforce primary observations and to simplify complex findings. These approaches are effective and are integral to assessment; however they may also be a source of bias or error. Improving outcomes and supporting diagnosis require the development of decision-support mechanisms that identify and support the benefits of heuristic strategies while identifying or avoiding associated biases.FundingThe CPD scheme is funded by participant subscription.