Thiopurine Metabolites
Also known as: 6MP Metabolites, 6TG Metabolites, Azathioprine Metabolites, Mercaptopurine Metabolites
Use
This assay measures the red-cell concentration of 6-MMP (formed from 6-MP by thiopurine methyltransferase) and also measures the concentration of the resulting 6-TG after removal of the mono-, di-, or tri-phosphates from the various 6-thioguanine nucleotides. Once thiopurine therapy has been undertaken and an equilibrated drug level is achieved (usually three to six months), literature suggests that the measurement of thiopurine metabolites is warranted in the following situations:
Special Instructions
Not provided.
Limitations
This test should only be performed for patients currently on thiopurine therapy, including those administering azathioprine or mercaptopurine. It may not be useful in patients with autoimmune hepatitis.
Methodology
Mass Spectrometry
Biomarkers
LOINC Codes
- 82869-9 - 6-TG and 6-MMP Pnl RBC
- 32660-3 - 6-TGN EntSub RBC
- 32654-6 - 6MMP EntSub RBC
Result Turnaround Time
6-12 days
Related Documents
For more information, please review the documents below
Specimen
Whole Blood
Volume
3 mL
Minimum Volume
1 mL
Container
Lavender-top (EDTA) tube
Collection Instructions
Collect blood in lavender-top (EDTA) tube only. Gently invert to mix. Submit whole blood refrigerated. Do not separate specimen. Do not freeze.
Storage Instructions
Refrigerate
Causes for Rejection
Frozen specimen; specimen not EDTA whole blood; gross hemolysis
Stability Requirements
| Temperature | Period |
|---|---|
| Room Temperature | 1 day |
| Refrigerated | 8 days |
| Frozen | unstable |
Other tests from different labs that may be relevant