lecithin/sphingomyelin ratio


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lecithin/sphingomyelin ratio

 (L-S ratio)
the ratio of lecithin to sphingomyelin in amniotic fluid, the determination of which is helpful in establishing the maturity of the fetus and its susceptibility to hyaline membrane disease after birth.

lec·i·thin/sphin·go·my·e·lin ra·ti·o (L:S ra·ti·o),

a ratio used to determine fetal pulmonary maturity, found by testing the amniotic fluid; when the lungs are mature, lecithin exceeds sphingomyelin by 2 to 1.

lecithin/sphingomyelin ratio

L/S ratio Obstetrics The ratio of lecithin–phosphatidyl choline to sphingomyelin, a 'bench' parameter used to determine lung maturity and predict an infant's ability to survive without developing respiratory distress. See Biophysical profile, Lung profile, Respiratory distress syndrome.