AMNIOTIC-FLUID LAMELLAR BODY COUNT - A RAPID AND RELIABLE FETAL LUNG MATURITY TEST

Objective: To evaluate the lamellar body count as a predictor of fetal lung maturity. Methods: We conducted a prospective clinical outcome s tudy. Amniocentesis was performed for evaluation of fetal lung maturit y status within 72 hours of delivery in 130 patients. A lamellar body count was performed on each specimen, and a lecithin-sphingomyelin rat io and lung phospholipid profile were performed when possible (insuffi cient sample or contamination in eight cases). Each infant was evaluat ed for evidence of respiratory distress syndrome (RDS). Results: A lam ellar body count exceeding 30,000/mu L predicted pulmonary maturity co rrectly in all cases (negative predictive value 1.00). All 16 cases of RDS had counts of 30,000/mu L or less. If the lamellar body count was less than 10,000/mu L, the positive predictive value for RDS was 67%, and the likelihood of a mature result from chromatographic phospholip id analysis was low (one of 14, 7%). Values between 10,000-30,000/mu L indicated intermediate risk (four of 39, 10%) for developing RDS. Pho spholipid analysis indicated fetal lung maturity in 35 of 39 (90%) cas es with lamellar body counts in the intermediate risk range. Conclusio ns: The lamellar body count compares favorably with traditional phosph olipid testing in the prediction of fetal lung maturity. Phospholipid analysis is not needed with lamellar body counts greater than 30,000/m u L or less than 10,000/mu L, but may be of benefit for values in the intermediate risk range. Advantages of this test include speed, object ivity, small sample volume required, and universal availability of ins trumentation.