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 study. Amniocentesis was performed for evaluation of fetal lung maturity status within 72 hours of delivery in 130 patients. A lamellar body count was performed on each specimen, and a lecithin-sphingomyelin ratio and lung phospholipid profile were performed when possible (insufficient sample or contamination in eight cases). Each infant was evaluated for evidence of respiratory distress syndrome (RDS). Results: A lamellar body count exceeding 30,000/mu L predicted pulmonary maturity correctly 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 phospholipid 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. Phospholipid analysis indicated fetal lung maturity in 35 of 39 (90%) cases with lamellar body counts in the intermediate risk range. Conclusions: The lamellar body count compares favorably with traditional phospholipid testing in the prediction of fetal lung maturity. Phospholipid analysis is not needed with lamellar body counts greater than 30,000/mu 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, objectivity, small sample volume required, and universal availability of instrumentation.