A B C D E F G H I J K L M N O P Q R S T U V W X Y Z # |
TPMT Activity
Test CodeTPMT
Quest Code
18831
Alias/See Also
18831
Thiopurine S-methyltranferase Activity / Azathioprine / Imuran
Thiopurine S-methyltranferase Activity / Azathioprine / Imuran
CPT Codes
84433
Preferred Specimen
4 mL whole blood collected in two of each separate EDTA (lavender-top) tubes
Minimum Volume
2 mL (x2)
Instructions
Collect venous blood in 2 separate EDTA (lavender-top) tubes (4 mL in 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 physician's discretion.
Blood is collected prior to azathioprine (Imuran) or 6-mercaptopurine (6-MP, Purinethol) therapy for screening purposes. The draw time is at physician's discretion.
Transport Temperature
Refrigerated (cold-packs)
Specimen Stability
Room temperature: 48 hours
Refrigerated: 9 days
Frozen: Unacceptable
Refrigerated: 9 days
Frozen: Unacceptable
Reject Criteria (Eg, hemolysis? Lipemia? Thaw/Other?)
Hemolysis • Clotted • Animal specimen • Forensic specimen
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 FDA. This assay has been validated pursuant to the CLIA regulations and is used for clinical purposes.
Setup Schedule
Sets up Sun-Thurs; Report available: 4-6 days
Report Available
Maximum Laboratory Turn Around Time 8 days
Reference Range
>12 | Normal |
4-12 | Heterozygote or low metabolizer |
<4 | Homozygote Deficient Range |
Clinical Significance
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.
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.
Performing Laboratory
Quest Diagnostics Nichols Institute
33608 Ortega Highway
San Juan Capistrano, CA 92690-6130