Evaluating the clinical effectiveness of amniotic fluid assays in predicting respiratory distress syndrome in the neonate
Amenta, J.S.; Brocher, S.C.; Serenko-Aber, A.L.
Clinical Chemistry 33(5): 647-652
1987
ISSN/ISBN: 0009-9147 PMID: 3568348 Document Number: 296365
Amniotic fluid phospholipids from 346 patients' specimens were quantified and evaluated against the clinical outcome (i.e., respiratory distress syndrome of normal respiratory function). Concentrations of lecithin, sphingomyelin, phosphatidylglycerol, and the lecithin/sphingomyelin reflectance ratio were evaluated by ordered frequency distribution and stepwise discriminant function analysis. The lecithin/sphingomyelin ration was the best single test for discriminating between respiratory distress syndrome and normal pulmonary function in the fetus, slightly superior to lecithin assay alone. A combination of lecithin/sphingomyelin ratio and lecithin concentration, however, appeared to optimize the discriminant function, although the clinical significance of this test combination remained marginal. High concentrations of phosphatidylglycerol were correlated with high concentrations of lecithin, and virtually ruled out respiratory distress syndrome. Absence of phosphatidylglycerol was not diagnostic. High concentrations of sphingomyelin increased the probability of respiratory distress syndrome. We suggest the following stepwise series of tests to optimize diagnosis: phosphatidylglycerol concentration, sphingomyelin concentration, and finally lecithin-sphingomyelin ratio.