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ID:941 Thioguanine Nucleotides (TGN)
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DescriptionThe assessment of the active thiopurine metabolites (6TGN & 6MMPN) of the thioguanine drugs azathioprine, 6-mercaptopurine and 6-thioguanine.
IndicationIt is particularly relevant to determine the correct treatment regimes in patients who have TPMT heterozygous status who exhibit a low TPMT enzyme activity where reduced dose regimes are being used or where it is unclear that therapeutic levels are being achieved.
Additional InfoPlease provide details of current thiopurine drug regime and patient diagnosis on the request form. PLEASE NOTE: Test is available to Bradford gastro, Leeds Paediatric oncology and Leeds Gastroenterology consultant requests.
Concurrent Testsna
Dietary Requirementsna
Interpretation235-450 pmol 6TGN/8x10^8 cells associated with maximum drug efficacy in inflammatory bowel disease. >5700 pmol 6MMPN/8x10^8 cells associated with increased risk of hepatotoxicity.

TubeEDTA (Haem)
Tube Picture
Collection ConditionsSuggested that the level of 6TGN is checked 4 weeks after commencing/changing the thiopurine drug dose as by this time steady state levels should have been achieved. Time of sampling need not be related to the time of administration of the parent drug.
Min. Vol4mL

Ref. Range (Male)
Ref. Range (Female)
Ref. Range (Paed)
Ref. Range NotesUnits - pmol metabolite / 8x10^8 cells
Units - Not Defined -
IP Acute TAT- Not Defined -
IP Routine TAT7 days
GP Acute TAT- Not Defined -
GP Routine TAT7 days
Turnround CommentNA

Originally edited by : RB. Review due on 02/06/2016 11:22:47. Published By RB on 02/06/2015 11:22:47.