tsh with reflex

specifically, what is a tsh with reflex test?  I know about tsh and free t 4 but have never heard of this test and got a result from a lab.
Thanks

[goolarra]

"TSH with reflex" is basically an instruction to the lab.  It means "do the TSH test, and if that is abnormal, do FT4 also"  So the TSH they came up with is just your TSH.  No difference.

[jjohnson5409]

But if your TSH is in the normal range and your FT4 has been running low, how would we know?   It just doesn't make any sense to me.  To save money!!!!    Now I have to get another test to retest the FT4 and Ft3 that was originally order!  is that right?  because they did n't do the FT3 either.  

[goolarra]

Bingo!  You basically hit the nail on the head!

You wouldn't know that your FT4 was running low.  TSH alone is virtually useless, but it's been the "gold standard" for so long that it's almost impossible to topple it off its pedestal.  It doesn't make any sense to me either, but we hear this ALL the time.

And FT3 is even more difficult.  Doctors are often very reluctant to order it.  I have to check every time I have blood drawn to make sure FT3 is included.  It's $10!  Believe me, I don't get it either.