title: The effect of maternal blood contamination on the TDx-FLM II assay.
abstract: The objective of this paper is to determine the effect of maternal blood contamination on the TDx-FLM II assay for fetal lung maturation. Thirty-one samples of amnionic fluid (AF) collected from gestations > 28 weeks were assayed for AF surfactant-to-albumin ratio using the TDx-FLM II assay. Maternal blood was added to the AF at increasing concentrations from 1:10 to 1:1280 and the TDx-FLM II was assessed on each sample. There were 7 mature (> 55), 5 transitional (40-54) and 19 immature (< 39) specimens. The addition of increasing amounts of maternal blood decreased the value of a mature and increased the value of an immature result. Six of the 7 mature values eventually became immature at high levels of contamination. No value below the mature cutoff was raised into the mature range by the addition of blood. Samples with values between 21 and 45 had a variable response to maternal blood but none were increased into the mature range. Maternal blood contamination may result in a falsely immature or borderline value, but mature results are valid regardless of the degree of contamination.
authors.affiliation: Department of Obstetrics and Gynecology, Arnold Palmer Hospital for Children and Women, Tampa, Florida, USA.
authors.forename: S J
authors.initials: SJ
authors.lastname: Carlan
authors.forename: D
authors.initials: D
authors.lastname: Gearity
authors.forename: W F
authors.initials: WF
authors.lastname: O'Brien
mesh_terms: D000649:Amniocentesis; D004912:Erythrocytes; D005260:Female; D005325:Fetal Organ Maturity; D005454:Fluorescence Polarization; D006801:Humans; D008168:Lung / Q000196:embryology*; D011237:Predictive Value of Tests; D011247:Pregnancy; D013048:Specimen Handling