Rapid fetal lung maturity testing: commercial versus NBD-phosphatidylcholine assay.
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.
Ashwood
E R
ER
Department of Pathology, University of Utah School of Medicine, Salt Lake City.
Palmer
S E
SE
Lenke
R R
RR
D000418:Albumins / Q000032:analysis; D000653:Amniotic Fluid / Q000737:chemistry*; D005325:Fetal Organ Maturity; D005454:Fluorescence Polarization / Q000295:instrumentation; D005456:Fluorescent Dyes; D008168:Lung / Q000196:embryology*; D010713:Phosphatidylcholines / Q000032:analysis; D010715:Phosphatidylglycerols / Q000032:analysis; D011296:Prenatal Diagnosis / Q000295:instrumentation / Q000379:methods*; D011663:Pulmonary Surfactants / Q000032:analysis*; D013109:Sphingomyelins / Q000032:analysis; D013997:Time Factors
D000418:Albumins; D005456:Fluorescent Dyes; D010713:Phosphatidylcholines; D010715:Phosphatidylglycerols; D011663:Pulmonary Surfactants; D013109:Sphingomyelins