A blind comparison study of the lung phospholipid profile, fluorescence microviscosimetry, and the...

Two hundred thirty-six amniotic fluid samples from 215 patients were analyzed for the acidic phospholipids, phosphatidylglycerol (PG) and phosphophatidylinositol (Pl), using two-dimensional chromatography. One hundred seventy-eight samples were compared for gestational age, 166 were compared with lecithin/sphingomyelin (L/S) ratios, and 56 compared with the FELMA microviscosimeter. Although Pl could be detected by the sixteenth gestational week, PG was not found earlier than the thirty-fifth week. Median L/S ratio in samples not containing PG was 1.94, while PG-positive fluid had a median ratio of 3.72 (p less than 0.001). One hundred twelve infants born within 72 hours were evaluated for outcome. No instance of hyaline membrane disease (HMD) occurred in any neonate with detectable PG regardless of L/S ratio, while 2 of 67 (3%) infants with mature L/S ratios developed HMD. The FELMA technique did not mispredict maturity in any neonate who subsequently developed HMD. Two samples contained PG but the neonates were delivered free of lung disease. The phospholipid lung profile appears to be the most accurate method for the evaluation of fetal lung maturity, while the FELMA technique, although less sensitive, is more rapid.