01081nas a2200253   4500000000100000008004100001260001300042653001200055653003800067653002700105653001100132653001200143653002300155653003200178653002400210100001900234700001300253700001400266245011500280300001100395490000600406520040100412022001400813       1988                            d  c1988 Jul10aDapsone10aEnzyme-Linked Immunosorbent Assay10aHemagglutination Tests10aHumans10aleprosy10aPatient Compliance10aSensitivity and Specificity10aStatistics as Topic1 aNagelkerke N J1 aFidler V1 aBuwalda M00aInstrumental variables in the evaluation of diagnostic test procedures when the true disease state is unknown.  a739-440 v73 a<p>We explore the estimation of sensitivity and specificity of diagnostic tests when the true disease state is unknown. Instrumental variables which subdivide the patient population are used. A logistic model, relating these instrumental variables to the (unknown) true disease state is proposed. It is shown that this procedure allows the goodness-of-fit to the resulting model to be tested.</p>  a0277-6715