Lamellar body count as a diagnostic test in predicting neonatal respiratory distress syndrome

AIM To determine the lamellar body count (LBC) cutoff value for fetal lung maturity and to evaluate the clinical usefulness of LBC in predicting the severity of neonatal respiratory distress syndrome (RDS). METHODS A prospective study was conducted from 2002 until 2010. LBC was estimated in uncentrifugated amniotic fluid samples using Cell-Dyn 1800 analyzer. Amniotic fluid samples were obtained by amniocentesis or by puncturing embryonic membranes during cesarean section. The presence of mild, moderate, and severe RDS was assessed by neonatologist. RESULTS A total of 313 patients with singleton pregnancies (24-41 weeks) were included in the study and 294 met the inclusion criteria. RDS was diagnosed in 28 neonates - mild in 8, moderate in 10, and severe in 10. In premature neonates (<37 gestational weeks), significant differences in LBC were only found between the subgroup without RDS and the group with moderate and the group with severe RDS (P<0.001). In all neonates, significant differences were found between neonates without RDS and neonates with RDS. Using LBC cutoff value of ≥20,000/µL, sensitivity, specificity, and positive and negative predictive values of LBC in determining mature fetal lungs were 96%, 88%, 45.6%, and 99.5%, respectively. CONCLUSION This study suggests that LBC cutoff value of ≥20,000/µL can predict pulmonary maturity and reduce the risk of neonatal respiratory distress syndrome.