Thiopurine Methyltransferase (TPMT), Phenotype
Thiopurine Methyltransferase (TPMT), Erythrocytes, Enzyme Activity
TPMT Activity Profile
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Liquid Chromatography-Tandem Mass Spectrometry (LC-MS/MS)
Detection of individuals with low thiopurine methyltransferase activity who are at risk for excessive myelosuppression or severe hematopoietic toxicity when taking AZA and for detection of individuals with hyperactive thiopurine methyltransferase activity who have therapeutic resistance to thiopurine drugs and may develop hepatotoxicity if treated with these drugs.
6-Methylmercaptopurine: 3.00-6.66 nmol/mL/hr; 6-Methylmercaptopurine riboside: 5.04-9.57 nmol/mL/hr; 6-Methylthioguanine riboside: 2.70-5.84 nmol/mL/hr.
* Reference ranges may change over time. Please refer to the original patient report when evaluating results.
Collect specimen in a lavender top tube (preferred); green top (sodium or lithium heparin) is acceptable. PLEASE NOTE: the TPMT, Erythrocytes, Enzyme Activity assays performed by Mayo Medical Laboratories (MML) and Prometheus are the same test, a quantitative measure of TPMT enzyme activity. If TPMT Enzyme Activity is requested, the specimen will be sent to Mayo Medical Laboratories unless the Prometheus assay is specifically requested. If the Prometheus assay is requested, the clinician must specify the enzyme or genetics test.
Collect specimen in a lavender top tube (preferred); green top (sodium or lithium heparin) is acceptable. Send intact whole blood, refrigerated.