Tracheal TDx fetal lung maturity test for assessing lung maturity in newborns with respiratory distress.

We evaluated a modified TDx-fetal lung maturity (FLM) test for estimating surfactant in small volume tracheal aspirates in 140 infants requiring mechanical ventilation. Respiratory distress syndrome was present in 75 infants, and 68 had TDx FLM less than 60 mg/dL (sensitivity, 90.6%). Respiratory distress was absent in 65 infants, 56 had TDx FLM more than 60 mg/dL (specificity, 86.1%). The modified TDx-FLM assay is highly automated, has a fast turn-around time (less than 30 minutes), has high reproducibility, and is less expensive than other available methods. This method has potential routine application in the diagnosis of surfactant deficiency, and the assessment of surfactant replacement and mechanical ventilation therapies.