Predicting fetal lung maturity by visual assessment of amniotic fluid turbidity: comparison with fluorescence polarization assay.
We prospectively studied 159 patients having clinically indicated amniocentesis. Amniotic fluid (3 to 5 mL) was placed in a nonheparinized glass tube. This sample was then classified as turbid (indicating maturity) or clear (indicating immaturity) on the basis of a single examiner's ability to read newspaper print through the glass tube. These results were then compared with fluorescence polarization values for the same sample. A value of 70 mg/g was considered positive evidence of fetal lung maturity. By study criteria, 62 samples (39%) indicated immaturity and 97 (61%) indicated maturity. Turbidity correctly identified 89 samples that produced fluorescence polarization values of at least 70 mg/g. Turbidity as a predictor of fetal lung maturity when compared with fluorescence polarization assay has a 91% positive and 87% negative predictive value. Visual inspection of amniotic fluid may be of value in areas where sophisticated methods are unavailable.
D000649:Amniocentesis; D000653:Amniotic Fluid / Q000737:chemistry*; D005260:Female; D005325:Fetal Organ Maturity; D005454:Fluorescence Polarization; D005865:Gestational Age; D006801:Humans; D008168:Lung / Q000196:embryology*; D009391:Nephelometry and Turbidimetry; D011237:Predictive Value of Tests; D011247:Pregnancy; D011446:Prospective Studies; D012680:Sensitivity and Specificity