RESUMO
The examination of amniotic fluid for the presence or absence of free-floating particles (FFPs) by real-time ultrasound was performed in 100 non-diabetic patients undergoing amniocentesis for maturity testing. A modified lecithin to sphingomyelin ratio (L/S ratio) was the gold standard of the test. The sensitivity and specificity were 97.6% and 62.5% respectively. The presence of FFPs had 93.2 positive predictive value and 83.3% negative predictive value. FFPs grade 2, 1, 0 had 100%, 70% and 16.7 positive predictive value respectively. The mean value of L/S ratio varied with the FFPs grading, with the mean of 5.09+ 2.48, 2.84 + 0.71, 2.02+ 0.01 in grade 2, 1 and 0 respectively. This study suggests that the presence of FFPs especially FFPs grade 2 on real-time ultrasound may be used to confirm fetal lung maturity.