TPMT Activity
Test code
CPT code(s)*
Test resources
Details
Methodology
Chromatography/Mass Spectrometry
Assay category
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.
Alternative name(s)
Azathioprine Toxicity,Mercaptopurine Toxicity,TPMT Deficiency
Specimen requirements | |
|---|---|
| Patient preparation | None Specified |
| Preferred specimen(s) | 4 mL whole blood collected in two of each separate tubes |
| Minimum volume | 2 mL (x2) |
| Collection 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. |
| Transport container | EDTA (lavender-top) tube(s) |
| Transport temperature | Refrigerated (cold-packs) |
| Specimen stability | Room temperature: 48 hours Refrigerated: 9 days Frozen: Unacceptable |
| Reject criteria | Hemolysis • Clotted • Animal specimen • Forensic specimen • Received frozen |
Reference Range(s)
| >12 | Normal metabolizer |
| 4-12 | Intermediate metabolizer |
| <4 | Poor metabolizer |
Reference ranges are provided as general guidance only. To interpret test results use the reference range in the laboratory report.
*The CPT codes provided are based on AMA guidance and are for informational purposes only. CPT coding is the sole responsibility of the billing party. Please direct any questions regarding coding to the payer being billed.
This material contains content from LOINC® (http://loinc.org). The LOINC Table, LOINC Table Core are copyright © 1995-2019, Regenstrief Institute, Inc. and the Logical Observation Identifiers Names and Codes (LOINC) Committee and is available at no cost under the license at http://loinc.org/license.
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