Actual state in the diagnosis of fetal lung maturity

Four methods of phospholipid analysis in amniotic fluid were compared: miniaturized version of a one-dimensional thin-layer chromatographic determination of the lecithin/sphingomyelin ratio; A one-dimensional thin-layer chromatographic separation of all phospholipid components in amniotic fluid; A completely enzymatic determination of amniotic fluid lecithin concentration; An immunological method for semiquantitative measurement of phosphatidylglycerol. The various phospholipid parameters (L/S ratio, lecithin concentration, phosphatidylglycerol detection either by thin-layer chromatography or immunological methods) show a strong correlation to advancing gestational age. While we were not able to prove a statistically significant correlation between enzymatic lecithin values or L/S ratio values and the occurrence of neonatal RDS cases in this study due to the relatively small number of RDS cases, the L/S ratio values obtained by one-dimensional thin-layer chromatography and the phosphatidylglycerol values, determined either chromatographically or immunologically, showed a clear correlation to the expected development of RDS in the newborn. Thus we can conclude that under the actual methods of amniotic fluid phospholipid evaluation immunological phosphatidylglycerol determination as well as the one-dimensional separation of amniotic fluid phospholipids, which is easier to run than the "lung profile" determination of Kulovich and Gluck provide good information about the exclusion of RDS.