Analytic Time

14 days

MiChart Code
Thiopurine Metabolites, 6-TG and 6-MMP
Soft Order Code

Test Updated:


6MMP and 6TG
6 Thioguanine (6 TG)
6 Methyl Mercaptopurine (6 MMP)
PRO-PredictRx Metabolites
Thiopurine Metabolites
Imuran Metabolites

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Test Overview

Test Methodology


Test Usage

Used to individualize dosing and balance therapeutic response with possible toxicity for patients on thiopurine therapy. Provides measurement of 6-TG (correlated with clinical response and leukopenia) and 6-MMP (correlated with hepatotoxicity) metabolites. Metabolite testing shuld not replace laboratory monitoring for toxicity.

Reference Range

6-TGN: 235 - 400 pmole/8x10(8) RBC, 6-MMPN: <5700 pmole/8x10(8) RBC.

* Reference ranges may change over time. Please refer to the original patient report when evaluating results.

Specimen Requirements

Collection Offsite

Collect specimen in a lavender top tube. Refrigerate and send intact specimen within 5 days of collection. Do not freeze.

Lavender Top Tube
Normal Volume
5 mL EDTA whole blood
Minimum Volume
3 mL EDTA whole blood

Billing Information

CPT Code
Pro Fee Code

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Our High Standard

Quality that sets us apart

As the reference laboratory division of Michigan Medicine's Department of Pathology, MLabs shares the institution's commitment to applying established quality principles to clinical laboratory testing. Like other large organizations in complex, consequential fields, we rely on an established approach to monitor quality throughout the testing process.