title: Lamellar body concentrations and the prediction of fetal pulmonary maturity.
abstract: OBJECTIVE
  Amniotic fluid lamellar body concentration was quantified in pregnancy and compared with the lecithin/sphingomyelin ratio and phosphatidylglyceryl to predict fetal lung maturity.
  
  
  METHODS
  Amniotic fluid was obtained from 56 patients at various gestational ages (16 to 42 weeks) and quantified on a Coulter counter set for particle size used for platelets (2 to 20 fl). The lamellar body concentration best agreeing with a mature lecithin/sphingomyelin ratio of 2 and with phosphatidylglycerol was determined. The lamellar body concentration cutoff was compared with the lecithin/sphingomyelin ratio and phosphatidylglycerol as a predicator of fetal lung maturity.
  
  
  RESULTS
  Lamellar body concentration increased exponentially with gestation (r = 0.70, p < 0.001), as did the lecithin/sphingomyelin ratio (r = 0.78, p < 0.001). The two tests correlated with each other linearly (r = 0.67, p < 0.001). The lamellar body concentration cutoff value that best agreed with both mature lecithin/sphingomyelin ratio and phosphatidylglycerol was 30,000/microliters (kappa-test 0.66 and 0.73, respectively). In 28 patients delivered within 72 hours the lamellar body concentration correctly predicted four cases of respiratory distress syndrome (100% sensitivity and specificity).
  
  
  CONCLUSIONS
  This study confirms that lamellar body concentration is a reliable and practical assay and should be evaluated further, especially for use in a community hospital setting.
authors.affiliation: Department of Gynecology and Obstetrics, Union Memorial Hospital, Baltimore, Maryland.
authors.forename: G
authors.initials: G
authors.lastname: Fakhoury
authors.forename: N H
authors.initials: NH
authors.lastname: Daikoku
authors.forename: J
authors.initials: J
authors.lastname: Benser
authors.forename: N H
authors.initials: NH
authors.lastname: Dubin
mesh_terms: D000653:Amniotic Fluid / Q000737:chemistry* / Q000166:cytology; D005260:Female; D005325:Fetal Organ Maturity / Q000502:physiology; D005865:Gestational Age; D006801:Humans; D007231:Infant, Newborn; D008168:Lung / Q000196:embryology*; D010713:Phosphatidylcholines / Q000032:analysis; D010715:Phosphatidylglycerols / Q000032:analysis; D011247:Pregnancy; D011296:Prenatal Diagnosis; D012044:Regression Analysis; D012127:Respiratory Distress Syndrome, Newborn / Q000175:diagnosis; D012680:Sensitivity and Specificity; D013109:Sphingomyelins / Q000032:analysis
chemical_list: D010713:Phosphatidylcholines; D010715:Phosphatidylglycerols; D013109:Sphingomyelins