THIO METHYL
Thiopurine Methyltransferase (TPMT)
EPIC Test Procedure Code: LAB3616
Synonyms:
Thiopurine Methyltransferase Phenotype,
Azathioprine Phenotype
TPMT Phenotype
TPMT3
Performing Lab:
Referral Laboratory
Patient Preparation:
Thiopurine methyltransferase (TPMT) enzyme activity can be inhibited by several drugs and may contribute to falsely low results. Patients should abstain from the following drugs for at least 48 hours prior to TPMT testing: naproxen (Aleve), ibuprofen (Advil, Motrin), ketoprofen (Orudis), furosemide (Lasix), sulfasalazine (Azulfidine), mesalamine (Asacol), olsalazine (Dipentum), mefenamic acid (Ponstel), trimethoprim (Proloprim), methotrexate, thiazide diuretics, and benzoic acid inhibitors.
Container Type:
lavender top (EDTA) tube
Specimen Type:
Whole blood
Preferred Volume:
5 mL
Alternate Specimens:
Green top (sodium or lithium heparin), dark blue top (metal free sodium heparin), or plasma gel tubes
Minimum Volume:
3 mL
Store and Transport:
Refrigerated
Stability:
Room Temperature- 6 days
Refrigerated - 6 days
Unacceptable Condition:
Gross Hemolysis: Reject
CPT Codes:
84433 - Thiopurine S- Methyltransferase TpMT (EAP 30021381)
Test Schedule:
Monday, Wednesday, Friday
Turnaround Time:
5-8 days
Method:
Liquid Chromatography Tandem Mass Spectrometry (LC-MS/MS)
Reference Ranges:
Please refer to the performing lab report for applicable reference ranges