Test Overview
Test Usage
Phenotypic test that provides a quantitative measurement of TPMT enzyme activity levels to assist physicians with azathioprine (Imuran) or 6-MP (Purinethol) dosing strategies. Individuals with low thiopurine methyltransferase are at risk of excessive myelosuppression.
Reference Range *
Normal TPMT Activity: >21.0 EU/mL; Intermediate TPMT Activity: 6.0-21.0 EU/mL; Low TPMT Activity: <6.0 EU/mL.
* Reference ranges may change over time. Please refer to the original patient report when evaluating results.
Test Details
Days Set Up
Monday - Friday
Analytic Time
5 - 8 days
Soft Order Code
TPMTE
MiChart Code
TPMT Enzyme, Erythrocytes
Synonyms
- Thiopurine Methyltransferase (TPMT), Phenotype
- TPMT Enzyme
- TPMTPHE
- TPMT Phenotype
- Thiopurine Methyltransferase (TPMT), Erythrocytes, Enzyme Activity
Laboratory
Sendout
Reference Laboratory
Prometheus 3320
Section
Special Testing
Specimen Requirements
Collection Instructions
Collect specimen in a lavender top tube. Refrigerate and send intact specimen within 5 days of collection. Do not freeze.
Normal Volume
5 mL EDTA whole blood
Minimum Volume
2 mL EDTA whole blood
Additional Information
Test sent to Prometheus Labs.
Billing
CPT Code
82657
Fee Code
36155