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

Abstract

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.

Peripheral blood morphology review and diagnostic proficiency evaluation by a new Spanish EQAS during the period 2011‐2019

“…Finally, in contrast to other results previously published, 4,5 in reactive specimens our participants showed a great concordance with respect to the RR. In the two reactive surveys, most of the laboratories recognized reactive lymphocytes in PBS, considering almost all of them an infectious mononucleosis as the corresponding diagnosis.…”

“…The role of the PBS review in the diagnosis of lymphoma with abnormal lymphoid cells circulating in blood is to provide the first morphological orientation of the lymphoid neoplasm and to suggest which immunophenotyping or molecular analysis tests should be performed. Challenges in reporting whether a smear containing lymphocytes is associated with a reactive or neoplastic disease were highlighted previously by van der Meer et al 3 In addition, previous quality assurance control surveys showed that neoplastic misclassification of reactive lymphocytes occurs in 10 to 26% of cases 4,5 . On the other hand, two proficiency testing surveys revealed that a total of 21% of neoplastic cases were assigned as reactive 5 .…”

“…Other studies have shown the lack of agreement between laboratories in the correct interpretation of peripheral blood diseases by PBS review and the usefulness of the EQAS in order to evaluate and improve the diagnostic skills of the laboratory participants 2‐5 . In this study, we evaluate the laboratory diagnostic proficiency from Spanish laboratories participating in the PBS review scheme during the last 9 years.…”

Training future haematologists, a privilege or a burden? “A trainer's view”

“…A deficiency of morphological skills has been compounded further by the fact that senior haematologists with a major interest in this area are few and far between, making it difficult to motivate trainees to develop such a future interest. Maintenance of morphological skills is of crucial importance (Hamilton et al , ; Brereton et al , ). In the future a lack of skilled trainers may necessitate the increasing use of digital aids (Brereton & Burthem, ).…”

Machine learning algorithms for accurate differential diagnosis of lymphocytosis based on cell population data

“…According to quality assurance control surveys from Canada and the UK, neoplastic misclassification of reactive specimens occurs in 10-26% of cases (Brereton et al, 2015;Johnston et al, 2016) while up to 21% of neoplastic cases are assigned as reactive (Johnston et al, 2016), highlighting the need for improvement. Evaluation of the leucocyte subpopulation using DXH800 (Beckman Coulter, Miami, FL) analysers yields cell population data (CPD) with information on volume, conductivity (mean population values and SD) and 10 different scatter measures (Briggs, 2009;Bain, 2015).…”