Thiopurine methyltransferase-13556
Test info
TPMT biochemical assay, myelotoxicity
Determination of TPMT levels that may be associated with toxicity of anticancer and anti-inflammatory drugs
For patients having an intrinsic low level of TPMT, recent RBC transfusion can variably increase their assayed enzymatic activity depending on the amount and circulating half-life of the transfused red blood cells.
Specimen
Immediately following collection, mix sample thoroughly by gently inverting 8 - 10 times, to prevent clotting
Dk green Sodium heparin (Na hep), no gel - 10mL
Immediately following collection, mix sample thoroughly by gently inverting 8 - 10 times, to prevent clotting
Lavender (EDTA), 10mL
Refrigerated (strict) - 14 days
Frozen - NO
- Frozen specimen
- Gross hemolysis
- Clotted specimen
Performance
Enzymatic endpoint/liquid chromatography/tandem mass spectrometry (LC/MS-MS)
Clinical and Interpretive info
Normal: 15.1 - 26.4 units/mL RBC
Heterozygous for low TPMT variant: 6.3 - 15.0 units/mL RBC
Homozygous for low TPMT variant: <6.3 units/mL RBC