title: The ROC curve in the evaluation of fasting capillary blood glucose as a screening test for diabetes and IGT.
abstract: OBJECTIVE
  To assess the performance of different cutoff points of fasting capillary glycemia (FCG) in the diagnosis of diabetes and impaired glucose tolerance (IGT) using the receiver operating characteristics (ROC) curve approach.
  
  
  METHODS
  This study included a sample of 4,019 subjects without a previous history of diabetes who were recruited for a confirmatory 2-h post-glucose challenge capillary glycemia from a larger sample of 21,847 individuals screened with FCG. The sensitivity and the specificity of FCG as a screening test were analyzed in the cutoff range 3.9-8.9 mmol/l, and the corresponding ROC curves were plotted to assess the performance of the test.
  
  
  RESULTS
  The screening test performance was better for diabetes than for IGT in the full range of cutoff points studied. Sensitivities ranged between 37.9 and 97.1% for diabetes and 1.8 and 94.4% for IGT; the areas under the ROC curves were 0.91 +/- 0.01 and 0.75 +/- 0.01, respectively. The cutoffs showing the best equilibrium between sensitivity and specificity approached 5.6 and 5.0 mmol/l for diabetes and IGT, respectively. Factors such as age, color, and family history of diabetes can affect the screening test performance.
  
  
  CONCLUSIONS
  ROC curves can provide useful information toward improving the usefulness of FCG as a screening test for abnormalities of glucose tolerance.
authors: Department of Internal Medicine, University of Rio Grande, Brazil.
authors: A L
authors: AL
authors: Bortheiry
authors: D A
authors: DA
authors: Malerbi
authors: L J
authors: LJ
authors: Franco
mesh_terms: D000328:Adult; D000368:Aged; D001786:Blood Glucose / Q000032:analysis*; D002196:Capillaries; D003920:Diabetes Mellitus / Q000175:diagnosis*; D005215:Fasting; D005260:Female; D018149:Glucose Intolerance / Q000175:diagnosis*; D006801:Humans; D008297:Male; D008875:Middle Aged; D012372:ROC Curve; D012680:Sensitivity and Specificity
chemical_list: D001786:Blood Glucose