Band 2, Heft 3

With the discovery of existing circulating cell-free fetal DNA (ccffDNA) in maternal plasma and the advent of next-generation sequencing (NGS) technology, there is substantial hope that prenatal diagnosis will become a predominately non-invasive process in the future. At the moment, non-invasive prenatal testing (NIPT) is available for high-risk pregnancies with significant better sensitivity and specificity than the other existing non-invasive methods (biochemical and ultrasonographical). Mainly it is performed by NGS methods in a few commercial labs worldwide. However, it is expected that many other labs will offer analogous services in the future in this fast-growing field with a multiplicity of in-house methods (e.g., epigenetic, etc.). Due to various limitations of the available methods and technologies that are explained in detail in this manuscript, NIPT has not become diagnostic yet and women may still need to undergo risky invasive procedures to verify a positive finding or to secure (or even expand) a negative one. Efforts have already started to make the NIPT technologies more accurate (even at the level of a complete fetal genome) and cheaper and thus more affordable, in order to become diagnostic screening tests for all pregnancies in the near future.

Busy clinician-educators are often tasked with remediating medical students who have deficits in clinical reasoning. In this essay, we share our early experience with providing less feedback and more practice to these trainees. We suggest that front line teachers can streamline their feedback to struggling reasoners by focusing solely on the problem representation and prioritized differential diagnosis of the main problem in their oral presentations and then engaging in repeated loops of feedback until the student achieves competency in real time. By receiving feedback targeted to the assessment alone and employing deliberate practice, struggling students have the opportunity to make concrete improvement during short-term clinical assignments. This remediation approach is feasible for busy clinician-educators and warrants formal study.

Background: Many diagnostic errors are caused by premature closure of the diagnostic process. To help prevent premature closure, we developed checklists that prompt physicians to consider all reasonable diagnoses for symptoms that commonly present in primary care. Methods: We enrolled 14 primary care physicians and 100 patients in a randomized clinical trial. The study took place in an emergency department (5 physicians) and a same-day access clinic (9 physicians). The physicians were randomized to usual care vs. diagnostic checklist. After completing the history and physical exam, checklist physicians read aloud a differential diagnosis checklist for the chief complaint. The primary outcome was diagnostic error, which was defined as a discrepancy between the diagnosis documented at the acute visit and the diagnosis based on a 1-month follow-up phone call and record review. Results: There were 17 diagnostic errors. The mean error rate among the seven checklist physicians was not significantly different from the rate among the seven usual-care physicians (11.2% vs. 17.8%; p=0.46). In a post-hoc subgroup analysis, emergency physicians in the checklist group had a lower mean error rate than emergency physicians in the usual-care group (19.1% vs. 45.0%; p=0.04). Checklist physicians considered more diagnoses than usual-care physicians during the patient encounters (6.5 diagnoses [SD 4.2] vs. 3.4 diagnoses [SD 2.0], p<0.001). Conclusions: Checklists did not improve the diagnostic error rate in this study. However further development and testing of checklists in larger studies may be warranted.

Background: Red cell distribution width (RDW) is a marker of iron-deficient anaemia that can also assist differentiation of other anaemias. RDW also has been suggested as an effective marker for earlier anaemia detection. The RDW-anaemia relationship was investigated in cross-sectional community patient data, and the capacity of RDW to predict the diagnostic value of second tier anaemia markers assessed. Methods: Routine and second tier assay data were provided by the laboratory Sullivan Nicolaides Pathology. The cohort was divided into male and female groups stratified by age, and correlation analyses assessed associations of RDW to haemoglobin and ferritin. Analysis of covariance (ANCOVA) was performed for both routine and second tier markers to investigate their significance for RDW prediction. Results: RDW had statistically significant negative correlation with haemoglobin for both sexes and age ranges (p<0.01). The RDW relationship with serum ferritin was non-linear, representing two populations. ANCOVA showed categorical ferritin as a significant RDW predictor for younger females, with vitamin B12 a significant RDW predictor for older men. Haemoglobin, mean corpuscular haemoglobin (MCH) and second tier iron markers (e.g., transferrin) were significant RDW predictors for both sexes and ages investigated. An individual longitudinal female case study showed RDW as very sensitive to haemoglobin decrease, with ferritin not as responsive. Conclusions: RDW had a significant negative association with haemoglobin in cross-sectional community patient data. ANCOVA showed ferritin as a significant RDW predictor for younger females only. This study confirms the utility of RDW as a marker for early anaemia detection, and useful to accelerated diagnoses of anaemia aetiology.

Background: Identification of errors in anatomic pathology is an important issue in medical practice. The main objective of this study was to determine the prevalence and characterize preanalytic errors in surgical pathology and cytology samples. We also intended to explore associations between error prevalence and procedures implemented in hospitals concerning the type of requisition forms, use of guidelines for case acceptance and existence of error notification system. Methods: We analyzed 10,574 cases in five Portuguese hospitals. The pathology laboratories recorded during 20 days all cases submitted with preanalytic errors, using an input form that allowed the identification of sample type, error description, action taken before error, the professional who detected the fail and the test cycle segment where it was identified. Subsequently, particular procedures in use for preanalytic phase were characterized for each hospital. Results: The prevalence of cases with error was 3.1% (330/10,574), 95% confidence interval: 2.8%–3.5%. Errors occurred in 4.1% (250/6079) of histology specimens and 0.9% (40/4477) of cytology specimens, and included errors in the requisition forms (2.6% error rate) and in the sample container (1.5% error rate). Acceptance of cases with error was the most frequent action (66.9%), followed by rejection (24.4%) and retention (8.7%). Conclusions: The existence of written norms for sample acceptance and error reporting systems to submitting services and patient safety department were proven to be associated to lower error prevalence.

The patient safety literature is full of exhortations to approach medical error from a system perspective and seek multidisciplinary solutions from groups including clinicians, patients themselves, as well as experts outside the traditional medical domain. The 7th annual International Conference on Diagnostic Error in Medicine sought to attract a multispecialty audience, and attempted to capture some of the conversations by engaging participants in a World Café, a technique used to stimulate discussion and preserve insight gained during the conference. We present the ideas generated in this session, discuss them in the context of psychological safety, and demonstrate the application of this novel technique.

A 20-year-old man developed bilateral forearm paresthesias after propping his elbows on the desk studying. He was diagnosed with ulnar neuropraxia and instructed to follow up with a neurologist. The symptoms continued and the patient was admitted for a formal workup of his neuritis. A Monospot test was positive. The patient was discharged with a diagnosis of infectious mononucleosis. A comment on his complete blood count, showing absolute lymphocytosis with atypical lymphocytes and rare blasts with flow cytometry recommended, was missed, possibly due to the fact that it was not highlighted red on the electronic medical record indicating an abnormal result. A month later, an outpatient diagnosis of B-lymphoblastic leukemia/lymphoma was made on flow cytometry. This case highlights cognitive errors in diagnosis, including premature closure and failing to ‘see’ key data, as well as vulnerabilities created by data display limitations of the electronic medical record.