All of the following are true with regards to fetal lung maturity except
Assessment of fetal lung maturity Lecithin/sphingomyelin ratio- L/S Ratio >2 indicates pulmonary maturity. It is a reliable indicator, however the single best indicator if asked would be Phosphatidyl Glycerol Phosphatidylglycerol in amniotic fluid is the final indicator of lung maturation and is the most reliable indicator of pulmonary maturity Saturated phosphatidylcholine more than or equal to 500 ng/ml indicates pulmonary maturity. Although phosphatidylcholine is the most impoant constituent of surfactant, its presence does not definitively indicate pulmonary maturity as it stas appearing in amniotic fluid as early as 24 weeks whereas phosphatidyl glycerol is its storage form and appears in amniotic fluid only after complete lung maturity Shake test/clement bubble test- Increasing dilutions of amniotic fluid are mixed with 96% ethanol, shaken for 15 seconds and inspected after 15 minutes for the presence of a complete ring of bubbles at the meniscus. If it is present, the test is positive and indicates maturity of the fetal lungs. Orange colored cells- Desquamated fetal cells obtained from the centrifuges amniotic fluid are stained with 0.1% Nile Blue Sulfate. Presence of orange colored cells>50% suggest pulmonary maturity. Lamellar body- Storage form of surfactant in the amniotic fluid. They can be counted as the size is same as that of platelets. A lamellar body count >30,000/ microlitre indicates pulmonary maturity.
Phosphatidyl choline is most impoant pa of surfactant
L:S ratio is the single best indicator of pulmonary maturity
More than 50% cells are orange in colour on Nile blue sulphate test
Phosphatidyl glycerol in amniotic fluid is 100% confirmatory of lung maturity
Obstetrics