In neonatal cholestasis, if the serum gamma glutamyl- transpeptidase (GGT) is more than 600 IU/L the most likely diagnosis is:

D. Biliary atresia(Ref: Nelson's 20/e p 1933)3 Enzymes reflect cholestasis: Alkaline phosphatase, 5'nucleotidase & Gamma glutamyl transpeptidase.About GGT in Cholestasis: (Normal value of GGT is 5-40IU/L)"GGT levels are commonly elevated to values more than 10 times normal in biliary atresia while in hepatic causes it is raised to about three times normal"Thus a value of 600IU/L in the patient in question reflects an elevation of more than ten times the normal value. The patient is thus likely suffering from 'biliary atresia'.