AMNIOTIC-FLUID PHOSPHOLIPIDS - NEW PREDICTIVE VALUES OF L S AND PG/S RATIOS/

The lecithin/sphingomyelin (L/S) ratio after cold acetone precipitatio n is widely used to predict fetal lung maturity. The separation of sat urated lecithin, the main component of surfactant, is the basis for us ing the precipitation procedure but there is still a controversy as to whether cold acetone precipitable lecithin can be equated with satura ted lecithin. Following up a previous paper in which the effect of col d acetone precipitation on phospholipids of amniotic fluid was studied , the present work reports that non-precipitated L/S and phosphatidylg lycerol/sphingomyelin (PG/S) ratios correlate well with the precipitat ed L/S ratio (r = 0.93, r = 0.84, n = 92). The predictive value of bot h non-precipitated L/S and PG/S ratios has been studied when a ''posit ive'' result predicts a precipitated L/S ratio greater than or equal t o 2.0, and proposes a L/S ratio greater than or equal to 4.7 and a PG/ S ratio greater than or equal to 0.8 to predict fetal lung maturity, w hen cold acetone precipitation step is omitted.