Diagnostic accuracy of rapid ph IGFBP-I assay for predicting preterm labor in symptomatic patients

Objective:to estimate sensitivity, specificity, positive and negative predictive values (ppv, npv) of insulin-like growth factor binding protein-1 (phigfbp-1) test in predicting preterm delivery in women with symptoms of preterm labor. secondary objectives were to compare test characteristics of the phigfbp-1 and fetal fibronectin (ffn) tests.study design:labor and delivery units in two calgary hospitals. subjects were 349 women with suspected labor between 24 and 35 weeks gestational age (ga). women had cervical phigfbp-1 test +/− and ffn testing. sensitivity, specificity, ppv and npv were estimated. primary outcome was birth <37 weeks ga.result:sensitivity of phigfbp-1 test for delivery <37 weeks was 0.39; specificity, 0.76; ppv, 0.24; npv, 0.86. npv of phigfbp-1 did not differ greatly from that of ffn testing (0.88).conclusion:npv did not differ between phigfbp-1 and ffn for delivery <37 weeks. neither test improves on pretest probability of delivery <37 weeks, so clinicians must decide whether the use of either test is justified.