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About This Test

Department: Biochemistry (referred)


  • EDTA (purple top)

Dedicated sample required


Turnaround Time:

6 - 8 weeks


Assessment of therapeutic levels of azathioprine, 6-mercaptopurine and 6-thioguanine

For assessment of TPMT status prior to initiation of azathioprine therapy, please request TPMT.

This test measures metabolites of azathioprine, 6-mercaptopurine and 6-thioguanine.

Indications include:

  • treatment of patients with low TPMT activity
  • suspected non-compliance
  • failure to respond to standard doses

Please state clinical details clearly

Other Comments:

Analysed at Birmingham Heartlands Hospital, Bordesley Green East, Birmingham, B9 5SS

Interpretive comments provided by referral laboratory.