Lecithin/Sphingomyelin ratio is done to assess the maturity of:

Ref: Cloherty's Manual of Newborn Care. 6th edition, Page 323Explanation:THE LECITHIN -SPHINGOMYELIN (L/S) RATIOAssessment of fetal lung maturity (FLM) prenatally by testing amniotic fluid obtained by amniocentesis.It is performed by thin-layer chromatography.The risk of RDS is very low if the L/S ratio is >2.Exceptions to L/S ratio >2 are:o Infants of diabetic mothers (IDMs)o Intrapartum asphyxiao Erythroblastosis fetalis.Other possible exceptions are intrauterine growth restriction (IUGR), abruptio placentae, preeclampsia and hydrops fetalis.Blood and meconium tend to elevate an immature L/S ratio and depress a mature L/S ratio.OTHER METHODSThe TDx-FLM 11 measures the surfactant- albumin ratio.Measured using fluorescent polarization technology.A value of >45 mg/g indicates maturity.Lamellar body counts in the amniotic fluid.Lamellar bodies are '"packages" of phospholipids produced by type II alveolar cells.A count of >50,000 lamellar bodies/microliter predicted lung maturity.