vAF glucose highly predictive of, but not sensitive for, infection

A low (<5 mg/dL) vaginal amniotic fluid (vAF) glucose measurement can predict the presence of intra-amniotic infection (IAI), and rule it out, but has a low sensitivity for the condition.

Researchers at Yale University retrieved amniotic fluid via transabdominal amniocentesis (aAF) from 35 consecutive women with preterm premature rupture of membranes (PPROM) and compared it with vaginal pool samples.

They found substantial agreement between aAF and vAF glucose concentrations, and that women with IAI had significantly lower aAF and vAF glucose levels than noninfected women. They calculated that a vaginal pool glucose measurement of less than 5 mg/dL had 47.1% sensitivity, 100% specificity, and 100% positive predictive value in identifying women with positive microbial cultures in their amniotic fluid.

Buhimschi CS, Sfakianaki AK, Hamar BG, et al. A low vaginal "pool" amniotic fluid glucose measurement is a predictive but not a sensitive marker for infection in women with preterm premature rupture of membranes. Am J Obstet Gynecol. 2006;194:309-316.