Placental alpha microglobulin-1 (AmniSure® test) for detection of premature rupture of fetal membranes

Abstract

This study was designed to detect the accuracy of the placental alpha microglobulin-1 (PAMG-1) (AmniSure(®) test) to diagnose premature rupture of the fetal membranes (PROM). This comparative prospective study was carried out over 2 years in Al-Rashid Maternity Hospital, Kuwait from January 2006 till January 2008. One hundred and fifty (150) pregnant women after 37 weeks gestation were included in this study for induction of labor and divided into two groups according to the presence or absence of PROM; 75 patients with PROM were included in group I and 75 patients without PROM were included in group II as controls. Patients with multiple pregnancies or fetal distress or vaginal bleeding or preterm labor or chorioamnionitis were excluded from this study. Trans-abdominal ultrasound was done to detect the gestational age and the amniotic fluid index (AFI ≤5 cm in PROM) followed by sterile speculum examination to detect amniotic fluid pooling from the cervical canal and for the collection of samples. In this study, the sensitivity and the specificity of PAMG-1 to diagnose PROM were 97.33 and 98.67%, respectively, compared with 84% sensitivity and 78.67% specificity for Ferning test and 86.67% sensitivity and 81.33% specificity for Nitrazine test. The positive predictive value (PPV) and negative predictive value (NPV) of PAMG-1 were 98.64 and 97.37%, respectively, compared with 79.74% PPV and 83.1% NPV for Ferning test and 82.28% PPV and 85.91% NPV for Nitrazine test. PAMG-1 was accurate (98%) for detection of PROM than Ferning (81.33%) or Nitrazine (84.0%) tests. Detection of the PAMG-1 in the vaginal fluid using AmniSure(®) test is an accurate method to diagnose rupture of the fetal membranes, with high sensitivity, specificity, negative and positive predictive values.