This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Gynaecology & Obstetrics
All of the following indicate Fetal lung maturity except? 
Select and explain. 
A. LecithiniSphingomyelin ratio >2, B. Positive shake test, C. Increased phosphatidyl glycerol, D. Blue cells in Nile Blue Test
D: Blue cells in Nile Blue Test
Answer: D: Blue cells in Nile Blue Test 
Explanation: Ans D. Blue cells in Nile Blue TestRef: DC Dutla's textbook of Obstetrics,9't' ed.All of the above are correct except that it is the presence of more than 50 % orange coloured cells in Nile Blue test that suggests fetal pulmonary maturity.