Rapid fetal lung maturity testing: commercial versus NBD-phosphatidylcholine assay

• Published in: Obstetrics and gynecology (New York. 1953) Vol. 80; no. 6; p. 1048
• Main Authors: Ashwood, E R, Palmer, S E, Lenke, R R
• Format: Journal Article
• Language: English
• Published: United States 01-12-1992
• Subjects: Albumins - analysis; Amniotic Fluid - chemistry; Fetal Organ Maturity; Fluorescence Polarization - instrumentation; Fluorescent Dyes; Lung - embryology; Phosphatidylcholines - analysis; Phosphatidylglycerols - analysis; Prenatal Diagnosis - instrumentation; Prenatal Diagnosis - methods; Pulmonary Surfactants - analysis; Sphingomyelins - analysis; Time Factors
• ISSN: 0029-7844

We compared the TDx Fetal Lung Maturity test and the fluorescence polarization method using 1-palmitoyl-2(6-[(7-nitro-2,1,3-benzoxadiazol-4- yl)amino]caproyl)phosphatidylcholine (NBD-phosphatidylcholine). Using 76 paired human amniotic fluid samples, the fluorescence polarization values of the two methods were found to have a strong nonlinear correlation (r2 = 0.946). Both assays can be completed in less than 1 hour, have excellent precision (between-day variation less than 2%), and indicate the amount of surfactant phospholipid relative to albumin. The FLM assay is calibrated with surfactant/albumin standards; therefore, the reported results (in mg/g) correlate inversely with polarization of NBD-phosphatidylcholine. Strong correlations were seen for both assays with the lecithin-sphingomyelin ratio and phosphatidylglycerol. The correlations indicate that the recommended reference range for FLM will have more false predictions of immaturity than the NBD-phosphatidylcholine assay.