Lamellar body counts for rapid fetal lung maturity testing.

OBJECTIVE

To evaluate amniotic fluid lamellar body counting as a fetal lung maturity test. Lamellar body particles can be rapidly counted using the platelet channel of most blood cell analyzers.

METHODS

We conducted a 3-year prospective clinical outcome study. During the interval under study, outcomes of 247 neonates were used to evaluate the test; 28 neonates developed respiratory distress syndrome (RDS). Lecithin-sphingomyelin ratio (L/S) was available for 187 cases.

RESULTS

All cases of RDS had lamellar body counts of 55,000/microL or less and L/S of 2.2 or less; 59% of cases with no RDS had counts greater than 55,000/microL and 70% of normal cases had L/S higher than 2.2.

CONCLUSION

Use of lamellar body counts is justified as a rapid screening test to predict fetal lung maturity. Immature results should be followed by a more specific test such as L/S.