Fetal fibronectin (Quick Check fFN test) versus placental alpha microglobulin-1 (AmniSure test) for detection of premature rupture of fetal membranes

摘要

Objectives: To compare accuracy of fetal fibronectin (fFN) versus placental alpha microglobulin-1 for detection of premature rupture of fetal membranes (PROM). Methods: Two hundred and twenty pregnant women >34 and <37 weeks were included in this comparative prospective study and divided into two groups according to presence or absence of PROM. The diagnosis of PROM was based on patient's history of sudden gush of water, pooling of amniotic fluid, positive ferning, positive nitrazine test, confirmed by visualization of fluid passing from the cervical canal and amniotic fluid index ≤5 cm measured by trans-abdominal ultrasound. Patients included in this study were examined by sterile speculum for visualization of membranes and for collection of samples (swabs) from posterior vaginal fornix. Results: Sensitivity and specificity of AmniSure test to diagnose PROM were 97.3 and 98.2 %, respectively, compared with 94.5 and 89.1 %, respectively, for fFN test. Positive predictive value, negative predictive value, and accuracy of AmniSure test to diagnose PROM were 98.2, 97.3, and 97.7 %, respectively, compared with 89.7, 94.2, and 91.8 %, respectively, for fFN test. Predictive values and accuracy of fFN test to diagnose PROM were statistically insignificant compared with predictive values and accuracy of ferning, nitrazine and AmniSure tests. Conclusion: fFN bedside test is better than nitrazine and ferning tests in detection of PROM, but is not suited for identification of clinically difficult cases with suspected PROM, because, it is influenceable and can give false-positive results in preterm labor, women >34 gestational weeks and after any vaginal manipulation without PROM.