Evaluation of the effect of meconium on assessment of fetal lung maturity status by TDxFLM II testing.

OBJECTIVE: To evaluate the effect of meconium contamination on the TDxFLM II assay. METHODS: Amniotic fluid was collected from patients undergoing amniocentesis for obstetric indications between 31 and 40 weeks of gestation. A baseline TDXFLM II value was obtained and compared with amniotic fluid contaminated with 1%, 5%, and 10% meconium by weight. RESULTS: Twenty-one samples were studied, and in every case the TDxFLM II value decreased once the meconium was added. There was no consistent rate of decrease that correlated with the percentage of meconium added. CONCLUSION: Meconium contamination decreases the TDXFLM II value. A clinician who performs this test in the presence of meconium can be reassured that the contamination will not give an artificially elevated result. If the result is in the mature range, one can be confident that the result would only be higher if meconium were not present.