L/S ratio

L/S ratio

Obstetrics The ratio of lecithin–phosphatidyl choline to sphingomyelin, a 'bench' parameter used to determine infant lung maturity and predict the infant's ability to survive without developing respiratory distress. See Biophysical profile, Lung profile, Respiratory distress syndrome.
McGraw-Hill Concise Dictionary of Modern Medicine. © 2002 by The McGraw-Hill Companies, Inc.