title: Accuracy of the Safer Dx Instrument to Identify Diagnostic Errors in Primary Care.
abstract: Diagnostic errors are common and harmful, but difficult to define and measure. Measurement of diagnostic errors often depends on retrospective medical record reviews, frequently resulting in reviewer disagreement.
  
  
  
  We aimed to test the accuracy of an instrument to help detect presence or absence of diagnostic error through record reviews.
  
  
  
  We gathered questions from several previously used instruments for diagnostic error measurement, then developed and refined our instrument. We tested the accuracy of the instrument against a sample of patient records (n = 389), with and without previously identified diagnostic errors (n = 129 and n = 260, respectively).
  
  
  
  The final version of our instrument (titled Safer Dx Instrument) consisted of 11 questions assessing diagnostic processes in the patient-provider encounter and a main outcome question to determine diagnostic error. In comparison with the previous sample, the instrument yielded an overall accuracy of 84 %, sensitivity of 71 %, specificity of 90 %, negative predictive value of 86 %, and positive predictive value of 78 %. All 11 items correlated significantly with the instrument's error outcome question (all p values ≤ 0.01). Using factor analysis, the 11 questions clustered into two domains with high internal consistency (initial diagnostic assessment, and performance and interpretation of diagnostic tests) and a patient factor domain with low internal consistency (Cronbach's alpha coefficients 0.93, 0.92, and 0.38, respectively).
  
  
  
  The Safer Dx Instrument helps quantify the likelihood of diagnostic error in primary care visits, achieving a high degree of accuracy for measuring their presence or absence. This instrument could be useful to identify high-risk cases for further study and quality improvement.
authors.affiliation: Houston Veterans Affairs Center for Innovations in Quality, Effectiveness and Safety, Michael E. DeBakey Veterans Affairs Medical Center and Baylor College of Medicine, 2002 Holcombe Boulevard 152, Houston, TX, 77030, USA.|Department of Family & Community Medicine, Baylor College of Medicine, Houston, TX, USA.
authors.forename: Aymer
authors.initials: A
authors.lastname: Al-Mutairi
authors.affiliation: Houston Veterans Affairs Center for Innovations in Quality, Effectiveness and Safety, Michael E. DeBakey Veterans Affairs Medical Center and Baylor College of Medicine, 2002 Holcombe Boulevard 152, Houston, TX, 77030, USA.
authors.forename: Ashley N D
authors.initials: AN
authors.lastname: Meyer
authors.affiliation: Department of Internal Medicine, University of Texas Medical School at Houston, Houston, TX, USA.|The University of Texas at Houston-Memorial Hermann Center for Healthcare Quality and Safety, Houston, TX, USA.
authors.forename: Eric J
authors.initials: EJ
authors.lastname: Thomas
authors.affiliation: The University of Texas at Houston-Memorial Hermann Center for Healthcare Quality and Safety, Houston, TX, USA.|RAND Corporation, Santa Monica, CA, USA.
authors.forename: Jason M
authors.initials: JM
authors.lastname: Etchegaray
authors.affiliation: Department of Pediatrics, Section of Critical Care Medicine, Baylor College of Medicine and Texas Children's Hospital, Houston, TX, USA.
authors.forename: Kevin M
authors.initials: KM
authors.lastname: Roy
authors.affiliation: Department of Pediatrics, Section of Critical Care Medicine, Baylor College of Medicine and Texas Children's Hospital, Houston, TX, USA.
authors.forename: Maria Caridad
authors.initials: MC
authors.lastname: Davalos
authors.affiliation: Department of Medicine, Baylor College of Medicine and Ben Taub Hospital - Harris Health System, Houston, TX, USA.
authors.forename: Shazia
authors.initials: S
authors.lastname: Sheikh
authors.affiliation: Houston Veterans Affairs Center for Innovations in Quality, Effectiveness and Safety, Michael E. DeBakey Veterans Affairs Medical Center and Baylor College of Medicine, 2002 Holcombe Boulevard 152, Houston, TX, 77030, USA. hardeeps@bcm.edu.
authors.forename: Hardeep
authors.initials: H
authors.lastname: Singh
mesh_terms: D003951:Diagnostic Errors / Q000706:statistics & numerical data*; D003955:Diagnostic Tests, Routine / Q000592:standards; D006801:Humans; D008499:Medical Records; D061214:Patient Safety / Q000592:standards / Q000706:statistics & numerical data; D011237:Predictive Value of Tests; D011320:Primary Health Care / Q000592:standards*; D058996:Quality Improvement; D012372:ROC Curve; D012189:Retrospective Studies; D012680:Sensitivity and Specificity; D013781:Texas
keywords: diagnostic error; diagnostic safety; measurement; patient safety; primary care; quality improvement