Name of test to check azathioprine levels?

A co-worker's daughter was put on azathioprine for a rare autoimmune condition (Behcets). She has started to flare and I suggested that they get the test that checks her levels to make sure she is in the therapeutic range and he wanted to know what the name of the test is called.

Anyone know what the name of the test is?

6-MMP and 6-TGN

You want the 6-TGN to be in therapeutic range without the 6-MMP becoming too high (the latter is hepatoxic if too high)

It's probably enough just to ask to have her azathioprine levels checked.

Roughly 10% of ibd patients will metabolise 6-TGN to 6-MMP, I was one of those patients (as was my sister actually) and was given allopurinol to reduce that reaction and get my 6MMP into therapeutic range. No idea if this applies for your friend's condition.