Table IV. Positive predictive value (PPV) of GE/well reported by PCR/ESI-MS and AF cultures for the identification of adverse pregnancy outcomes.

	sPTD < 37 weeks	sPTD < 32 weeks	Delivery within 7 days of amniocentesis	Delivery within 2 days of amniocentesis
Prevalence	79.6% (113/142)	52.6% (50/95)	37.3% (53/142)	21.1% (30/142)
PPV of positive culture	90% (9/10)	66.7% (4/6)	70% (7/10)	50% (5/10)
PPV of PCR/ESI/MS (GE/well ≥17)	94.1% (16/17)	91.7% (11/12)	88.2% (15/17)	76.5% (13/17)

AF: amniotic fluid; PCR: polymerase chain reaction; ESI-MS: electrospray ionization mass spectrometry; GE/well: genome equivalent per PCR reaction.