Accuracy of amniotic fluid lamellar body counting for evaluating fetal lung maturity

Respiratory distress syndrome (RDS) is one of the important causes of mortality in neonates. This study was designed to assess the role of the amniotic fluid lamellar body counting in predicting fetal lung maturity.

This study was conducted during 2010, April to 2011, February, at Isfahan University of Medical Sciences, Isfahan, Iran. One hundred and twenty eight amniotic fluid samples were obtained during normal delivery, or before rupturing the membrane in cesarean, and lamellar body was assessed by cellular counter. The respiratory statuses of neonates were determined at delivery and the optimal cut-off point was assessed by receiver operating characteristic (ROC) curve. Sensitivity, specificity, positive predictive value (PPV) and negative predictive value (NPV) were evaluated in optimal cut-off point.

One hundred and twenty eight amniotic samples and 131 infants were evaluated. The means of maternal and gestational ages were 28.12 +/- 3.84 years and 32.56 +/- 2.72 weeks, respectively. The mean of lamellar body was 31266 +/- 15831 microl in matured lung infants compared to 63081 +/- 16966 microl in immature lung infants (p < 0.001). The optimal cut-off point was evaluated as 47500 microl in predicted pulmonary maturity with sensitivity of 85.1%, specificity of 91.2%, positive predictive value of 92.6% and negative predictive value of 82.5%.

This study indicated that lamellar body counting test has a high positive predictive value with a good sensitivity, specificity and negative predictive value. Future studies for different cellular counters are warranted.