PERFORMANCE OF THE DIPALMITOYL PHOSPHATIDYLCHOLINE TEST IN PREDICTINGRESPIRATORY-DISTRESS SYNDROME IN CONTAMINATED SAMPLES OF AMNIOTIC-FLUID

Objective: To evaluate the reliability of the dipalmitoyl phosphatidyl choline test in predicting respiratory distress syndrome (RDS) in the presence of common contaminants of amniotic fluid. Methods: Forty spec imens of amniotic fluid collected within 72 hours of delivery were div ided in five 25 mu L aliquots and diluted with either phosphate-buffer ed saline (control), meconium, blood, vaginal fluid, or semen. The con centration of dipalmitoyl phosphatidylcholine in all five groups of sa mples, as measured by the dipalmitoyl phosphatidylcholine test, was co mpared by paired t test, Dunnett test, and analysis of variance, and c orrelated with the neonatal respiratory status of the newborns. Result s: No significant differences in the concentration of dipalmitoyl phos phatidylcholine were found between control and the corresponding conta minated samples (P =.33). Of the 200 samples evaluated, 80 had dipalmi toyl phosphatidylcholine concentrations below 12 mu g/mL and 120 had a t least 12 mu g/mL. Using a cutoff dipalmitoyl phosphatidylcholine con centration of 12 mu g/mL, the presence of RDS was predicted accurately in all 15 control and in 61 of 65 contaminated samples. The absence o f RDS, as predicted by a dipalmitoyl phosphatidylcholine value at leas t 12 mu g/mL, was predicted accurately in 24 of 25 control samples and 96 of 100 contaminated samples. The overall accuracy of the dipalmito yl phosphatidylcholine test in predicting RDS in contaminated samples was 98%. Conclusion: The dipalmitoyl phosphatidylcholine test is a rel iable predictor of RDS in contaminated samples. (C) 1997 by The Americ an College of Obstetricians and Gynecologists.