Validation of a simple rapid high performance liquid chromatographic method for amniotic fluid lecithin/sphingomyelin ratios

A simple, rapid and sensitive HPLC method for the determination of L/S ratios in amniotic fluids is described. The method is based on isocratic separation in the normal phase with UV detection. The procedure has good precision and was validated clinically and by comparison with a routine TLC method. Although L/S ratios differed from those obtained by TLC, the clinical correlation between these methods was good. In single and serial samples from 39 mothers (42 babies) the HPLC method predicted respiratory distress syndrome (RDS) in all 9 babies with L/S ratios less than 7. No babies with ratios above 7 developed RDS. This method has potential clinical usefulness for the assessment of fetal lung maturity.