how to investigate 6 month mildly jaundiced boy.

6 month old male infant  presented in my clinic 1 week ago with mother  with c/o yellow urine and poor oral intake. All exminations except soft 4 cm palpable Liver was found.I didnt believe the mother as icterus was not apparent.This baby was NVD ,3 kg born with absolutely normal history till now.There is no hist of jaundice,fever,ftt at present or past.Now his wt is 6.9kg. There is no hist of pale stool. No hist of any fetal loss or jaundice or any hemoglobinopathy or any significant hist in family.

CBC is normal hb 12,retics 1%,normal wbc.Ur culture has no growth. TSB 1.6,Direct bilirubin 0.5(31%),SGPT 45.So have advised UDCA for a week and then plan is to review the baby.Repition of these tests and Thyroid will be done in next visit.But till now no hypothyroid features has developed. So if the situation dosent improve how i can reach the diagnosis doing minimal investigations so that…