title: Estimating sensitivity and specificity when repeated tests are performed on the same subject.
abstract: BACKGROUND
  When diagnostic tests are repeated on the same subject, a correlation between test results is expected. This must be taken into account when computing interval estimates.
  
  
  METHODS
  The application of regression techniques for correlated data to a logistic model is proposed in order to obtain correct point and interval estimates.
  
  
  RESULTS
  The use of different study designs and models of analysis (marginal and 'random effects') is discussed. The advantages of studies using multiple tests, possible sources of bias (including those specific to multiple testing) and methods of correction are also discussed. An example considering Doppler flow velocimetry in pregnancy is presented.
authors.affiliation: Unit of Cancer Epidemiology, Department of Oncology, Torino, Italy.
authors.forename: G
authors.initials: G
authors.lastname: Ronco
authors.forename: A
authors.initials: A
authors.lastname: Biggeri
mesh_terms: D005260:Female; D005865:Gestational Age; D006801:Humans; D015233:Models, Statistical; D011237:Predictive Value of Tests; D011247:Pregnancy; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity