| Description |
The measurement of amniotic fluid surfactant is the most reliable way to prenatally assess fetal lung maturity (FLM). Whereas previous studies compared a limited number of methods for assessing fetal maturity, this study compares 10 different methods. These methods are: lecithin/spingomyelin (L/S) ratio, phosphatidylglycerol (PG) determination by thin lay chromatography (TLC), immunologic test for PG, optical density (OD) at 650 nm, foam stability (FS), fluorescence polarization FP< creatinine, alkaline, phosphatase/gama-glutamyltransferase (ALK/DDT) ratio, glucose and angiotensin converting enzyme ACE). The study was designed to compare these various methods with the L/S ration, the reference method in FLM testing. Established statistical practices were used in the comparison of the data. Samples contaminated with blood or meconuim were not used. For the purpose of the study, a clinical evaluation of the newborn was not done because of the time constraints required to do the evaluations, and the fact that many studies have well established the predictability of the L/S ratio in FLM. Using multiple regression analysis, the data from two test were combined and then compared to the L/S ratio, to determine if the two test together could better predict FLM than the L/S ration. Our results indicate that no two tesst were better than the L/S/ ratio. A discussion of sensitivity and specificity as it relates to these studies is presented, and the importance of both is stressed. For each of the tests, sensitivity and specificity were calculated. The FP test had the best sensitivity (94%) and specificity (72%); all other test had very low specificities, but with appropriate sensitivities. It is recommended that these test be used only for screening; if the results is negative, an L/S ration should be performed. |
