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Laboratory Medicine

Test catalogue

Azathioprine Metabolites

Test Name

Azathioprine Metabolites (6-Thioguanine, 6-TG, 6-Methylmercaptopurine, 6-MMP, Immunosuppressant, Immuran )

Lavender Tube Specimen Type / Requirements

Container Type = 1 Lavender (EDTA)

Minimum Volume = 5 ml Whole Blood

Tube must fill to at least ½ or greater of its vacuum capacity

Specimen Handling

Collection Instructions:

Collect sample in Lavender (Purple EDTA)top. Collect trough specimen 0-30 minutes prior to next dose. Write your initials, date and time of collection on the collection label.

Laboratory Staff Instructions

Send whole blood at room temperature

Rejection Criteria:

Serum or plasma. Unlabeled or Not Sufficient Quantity Samples will be rejected.


Send sample to core lab as soon as possible.

Required Documentation

Turnaround Time (TAT)

10 Days

Test Utilization

Routine >10 Days

Reference Value

6-Methylmercaptopurine (6-MMP)

Therapeutic: < 6600 pmol/8x10*8 RBC

Critical: > 6600 pmol/8x10*8 RBC

6-Thioguanine (6-TG)

400 - 750 pmol/8x10*8 RBC

Test Code




Testing Location

Referred Out – ON, Canada (ROICL02)

Other Information