title: Sample size estimation in diagnostic test studies of biomedical informatics.
abstract: OBJECTIVE
  This review provided a conceptual framework of sample size calculations in the studies of diagnostic test accuracy in various conditions and test outcomes.
  
  
  METHODS
  The formulae of sample size calculations for estimation of adequate sensitivity/specificity, likelihood ratio and AUC as an overall index of accuracy and also for testing in single modality and comparing two diagnostic tasks have been presented for desired confidence interval.
  
  
  RESULTS
  The required sample sizes were calculated and tabulated with different levels of accuracies and marginal errors with 95% confidence level for estimating and for various effect sizes with 80% power for purpose of testing as well. The results show how sample size is varied with accuracy index and effect size of interest.
  
  
  CONCLUSIONS
  This would help the clinicians when designing diagnostic test studies that an adequate sample size is chosen based on statistical principles in order to guarantee the reliability of study.
authors.affiliation: Dept of Social Sciences and Health, Babol University of Medical Sciences, Babol, Iran. Electronic address: drhajian@yahoo.com.
authors.forename: Karimollah
authors.initials: K
authors.lastname: Hajian-Tilaki
mesh_terms: D000465:Algorithms; D016001:Confidence Intervals; D003955:Diagnostic Tests, Routine / Q000379:methods*; D006801:Humans; D016013:Likelihood Functions; D008490:Medical Informatics / Q000379:methods*; D015233:Models, Statistical; D012372:ROC Curve; D015203:Reproducibility of Results; D012107:Research Design; D018401:Sample Size; D012680:Sensitivity and Specificity
keywords: Area under the curve; Diagnostic studies; ROC analysis; Sample size; Sensitivity; Specificity