6-Thioguanine Nucleotides

Pathology category

Biochemistry - referred tests

Code

6TGN

Referral code

Request form

Test information

Assessment of the therapeutic levels of thioguanine drugs that are being achieved. Of paricular use in patients who are heterozygous for the TPMT enzyme where reduced dose regimes are being used or where it is unclear that therapeutic levels are being achieved.

Guidelines

Pre-analytical

It is suggested that the level of 6-TGNs 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.

Reference range

see report

Tube type

Tube type info

EDTA

Special requirements

Whole blood EDTA

Minimum volume

4 mL

Assay frequency

TAT Inpatient (urgent)

TAT Inpatient

2 weeks

TAT GP/Outpatient

2 weeks

Referral lab

Clinical Biochemistry City Hospital Birmingham