Lamellar body counts on gastric aspirates for prediction of respiratory distress syndrome

Aim:  To develop a rapid method for diagnosing lung maturity at birth with the purpose of administering surfactant early to infants with immature lungs and to spare infants with mature lungs from this treatment. Methods:  Lamellar body counts (LBC) on gastric aspirates from 191 newborns were counted in the platelet window in automatic blood cell counters. A preliminary study was performed on 108 aspirates from 2000 in infants with <32 weeks' gestation. Furthermore 83 aspirates from 2004-05 in infants with <30 weeks' gestation were analysed. Results:  Lamellar bodies in gastric aspirate were identified by electron microscopy. 70 of the aspirates from 2004-05 were analysed with a Sysmex XE-2100 counter. 24 of these infants developed moderate to severe respiratory distress syndrome (RDS). The best cut-off value was 8,000/μl with a sensitivity of 75% and a specificity of 72%. 44 of the 70 aspirates from 2004-05 were analysed both by Sysmex, Advia 120, and Cell-Dyn 4000. 13 other aspirates from 2004-05 were analysed by Sysmex and Coulter Counter LH755. Using Advia and Coulter the results were similar to Sysmex, but LBC obtained with Cell-Dyn were not correlated with the development of RDS. Conclusion:  LBC on gastric aspirate is a promising tool for prediction of development of RDS in infants of <30 weeks`gestation.