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

Abstract

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 þ /À 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.

Insulin-like growth factor binding protein-1 (IGFBP-1) during normal pregnancy

“…Phosphorylated IGFBP-1 is produced by the uterine decidua and the concentration of phosphorylated IGFBP-1 has been used as a marker for preterm labor [31]. IGFBP-1 thus seems to have several important roles during pregnancy from implantation to delivery.…”

New biomarkers for the prediction of spontaneous preterm labour in symptomatic pregnant women: a comparison with fetal fibronectin

“…These tests, however, have limited application in identifying women who will deliver preterm, because of their relatively low sensitivity and poor positive predictive values (PPVs). 5,6 In contrast, their utility relies on their high negative predictive value (NPV) in recognising women who are unlikely to deliver preterm.…”

Tests to predict imminent delivery in threatened preterm labour

“…A more recent prospective observational study confirmed high NPV, but poor PPV, for preterm birth within seven days or two weeks (table). 10 The test is cheaper than fetal fibronectin, and the high NPV supports its use as a "rule out" test (directing resources and treatment away from women at low risk), rather than for positive prediction.…”