<prompt> LecithinSphingomyelin ratio is done to assess the maturity of:LungFetal circulationBrainGonad  <response>: Ref: Clohertys Manual of Newborn Care. 6th edition, Page 323Explanation:THE LECITHIN -SPHINGOMYELIN LS 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 LS ratio is 2.Exceptions to LS ratio 2 are:o Infants of diabetic mothers IDMso 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 LS ratio and depress a mature LS ratio.OTHER METHODSThe TDx-FLM 11 measures the surfactant- albumin ratio.Measured using fluorescent polarization technology.A value of 45 mgg 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 bodiesmicroliter predicted lung maturity. 