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 am-nionic
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.
Bloody amniotic fluid - lung maturity
