Prediction of respiratory distress syndrome by the novel dipalmitoyl phosphatidylcholine test

Objective: To determine the accuracy of a new test that measures the concentration in amniotic fluid (AF) of dipalmitoyl phosphatidylcholine (DPPC) in predicting respiratory distress syndrome (RDS). Methods: The neonatal respiratory status of 176 newborns delivered within 72 hours of sampling was correlated with the concentration of DPPC, fluorescence polarization (TDx-FLM), lecithin-sphingomyelin ratio (US), and phosphatidylglycerol (Amniostat-FLM) in AF. Results: Thirty infants developed RDS (17%), all correctly predicted with DPPC values less than 12 mu g/mL (sensitivity 100%). Only six of the 146 cases with no RDS had DPPC values less than 12 mu g/mL (specificity 96%). The overall accuracy of the DPPC test was 98% compared with 70% for TDx-FLM, 71% for the L/S, and 67% for Amniostat-FLM. Receiver operating characteristic analysis area was 0.98 +/- 0.01, indicating that the DPPC test is superior to both the TDx-FLM and L/S tests. Conclusion: The DPPC test is an accurate predictor of RDS and fetal lung maturity.