Estimation of fetal lung maturity by assessment of lamellar body particle concentration

The concentration of lamellar bodies expressed as the optical density at 700 nm in amniotic fluid samples was calculated after centrifugation of the samples to obtain the lamellar bodies in a relatively pure form. The lamellar body concentrations obtained were compared with lecithin-sphingomyelin (L/S) ratios from the same samples. The advantages of the method compared with the L/S ratio are discussed as is the dependence on total volume that the method shares with all other procedures which depend on the measurement of a single concentration.