TPMT and NUDT15
Also known as: TPMT2
Use
This genotyping test assesses genetic risk for severe myelosuppression with standard dosing of thiopurine drugs in individuals for whom thiopurine therapy is being considered or who have had an adverse reaction to this therapy. Variants in TPMT and NUDT15 affect the inactivation of thiopurine drugs, which is used for autoimmune diseases, inflammatory bowel disease, acute lymphoblastic leukemia, and to prevent rejection after solid organ transplant. Accumulation of cytotoxic metabolites from these variants leads to increased risk of drug-related toxicity.
Special Instructions
Not provided.
Limitations
Only targeted TPMT and NUDT15 variants will be detected by this test. The complex TPMT*3A allele contains the variants found in the *3B and *3C alleles; therefore, the test cannot distinguish the *3A/negative genotype (intermediate enzyme activity) from the rare *3B/*3C genotype (no or low enzyme activity). Genotyping may reflect donor status in patients who have received allogeneic stem cell or bone marrow transplants within 2 weeks of specimen collection. Diagnostic errors can occur due to rare sequence variations, and genotyping does not replace therapeutic drug monitoring and clinical observation. Analytical sensitivity and specificity are greater than 99 percent.
New York Approved
Methodology
PCR-based (PCR)
Biomarkers
TPMT, NUDT15
Gene
Result Turnaround Time
5-10 days
Related Documents
For more information, please review the documents below
Specimen
Whole Blood
Volume
3 mL
Minimum Volume
1 mL
Container
Lavender (EDTA), pink (K2EDTA), or yellow (ACD solution A or B)
Storage Instructions
Refrigerated transport is preferred.
Causes for Rejection
Plasma or serum specimens, and specimens collected in sodium heparin or lithium heparin. Also, frozen specimens in glass collection tubes.
Stability Requirements
| Temperature | Period |
|---|---|
| Room Temperature | 3 days |
| Refrigerated | 1 week |
| Frozen | 1 month |
Other tests from different labs that may be relevant