Bilirubin in Amniotic Fluid Does Not Interfere with the Abbott TDx FLM II Assay

[摘要] Bilirubin, a breakdown product of lysed red blood cells, is present in amniotic fluid in very small concentrations relative to serum (1). In an uncomplicated pregnancy, bilirubin in amniotic fluid peaks at ∼19–22 weeks of gestation at concentrations of 1.6–1.8 mg/L (1). Rh isoimmunization and its severe manifestation, erythroblastosis fetalis, are associated with intrauterine hemolysis, which leads to increases in amniotic fluid bilirubin concentrations (2) up to 9.6 mg/L (3)(4). The assessment of fetal lung maturity (FLM) in these pregnancies is sometimes necessary, but the ability to utilize current methods in the presence of increased bilirubin concentrations is unclear. The commercial TDx FLM II assay (Abbott Laboratories), which is based on fluorescence polarization technology and the dye PC-16 (5), is the most commonly used method to assess FLM (6). Although the manufacturer does not recommend testing icteric amniotic fluid samples, nothing has been published about the nature or quantification of their interference with the TDx FLM II assay. Our objective was to examine the effect of bilirubin on TDx FLM II concentrations.Frozen leftover amniotic fluid samples sent to the laboratory for physician-ordered FLM testing …

[学科分类] 过敏症与临床免疫学