How many weeks after starting to take eltroxin , can we take blood test to test the ft3 ft4 and tsh values...( Now am on my 5th week taking eltroxin) ?? And while taking blood test in the morning , should I take eltroxin and then take blood test ?? Or without taking eltroxin should I take blood test ? Am confused.. each one saying different things.. v should nd v should not.. pls help !