TPMT Activity
Test Summary
Help prevent hepatotoxicity from thiopurine therapy.
This test helps identify individuals at increased risk of hepatotoxicity from thiopurine dose escalation. Patients with a TMPT activity of 4-12 nmol 6-MMP/hr/mL RBC (heterozygote/low metabolizer) are at increased risk and may require a lower dose of thiopurine drug.
Aliases
- N/A
Specimen Collection
Special Instructions
N/A
Preferred Specimen
4 mL whole blood collected in two EDTA (lavender-top) tubes
Minimum Volume
2 mL (x2)
Instructions
Collect venous blood in 2 separate EDTA (lavender-top) tubes (4 mL each tube). Ship at 2-8°C (refrigerated) within 24 hours of collection. Blood is collected prior to azathioprine (Imuran) or 6-mercaptopurine (6-MP, Purinethol) therapy for screening purposes. The draw time is at the physician's discretion.
Patient Preparation
N/A
Storage
N/A
Transport Temperature
Refrigerated (cold packs)
Specimen Stability
- Room Temperature = 48 hours
- Refrigerated = 9 days
- Frozen = unacceptable
Limitations
N/A
Other Acceptable Specimens
N/A
Unacceptable Specimens
Hemolysis • Animal specimen • Received clotted • Forensic specimen
Order Code
TPMT
EPIC (Premier) Code
LAB4540
Includes
N/A
CPT Code
- 84433
Billing Code
- 700000
CPT Statement
Methodology
Chromatography/Mass Spectrometry
FDA Status
This test was developed and its analytical performance characteristics have been determined by Quest Diagnostics. It has not been cleared or approved by the U.S. Food and Drug Administration. The FDA has determined that such clearance or approval is not necessary. This assay has been validated pursuant to the CLIA regulations and is used for clinical purposes.
Physician Attestation of Informed Consent
N/A
Testing Laboratory
Quest Diagnostics Nichols Institute
33608 Ortega Highway
San Juan Capistrano CA, 92675
33608 Ortega Highway
San Juan Capistrano CA, 92675
Reference Range
| >12 | Normal |
| 4-12 | Heterozygote or low metabolizer |
| <4 | Homozygote Deficient Range |
Setup Schedule / Expected Turnaround Time
Monday - Thursday; Report available: 4 - 6 days
Specimen Collection
Special Instructions
N/A
Preferred Specimen
4 mL whole blood collected in two EDTA (lavender-top) tubes
Minimum Volume
2 mL (x2)
Instructions
Collect venous blood in 2 separate EDTA (lavender-top) tubes (4 mL each tube). Ship at 2-8°C (refrigerated) within 24 hours of collection. Blood is collected prior to azathioprine (Imuran) or 6-mercaptopurine (6-MP, Purinethol) therapy for screening purposes. The draw time is at the physician's discretion.
Patient Preparation
N/A
Storage
N/A
Transport Temperature
Refrigerated (cold packs)
Specimen Stability
- Room Temperature = 48 hours
- Refrigerated = 9 days
- Frozen = unacceptable
Limitations
N/A
Other Acceptable Specimens
N/A
Unacceptable Specimens
Hemolysis • Animal specimen • Received clotted • Forensic specimen
Result Information
Methodology
Chromatography/Mass Spectrometry
Testing Laboratory
N/A
Reference Range
| >12 | Normal |
| 4-12 | Heterozygote or low metabolizer |
| <4 | Homozygote Deficient Range |
Setup Schedule / Expected Turnaround Time
Monday - Thursday; Report available: 4 - 6 days