Blood or bone marrow in a purple-top (EDTA) tube. Saliva is also acceptable.
Storage/Transport Temperature
For CHOP Phlebotomy: Samples can be collected throughout the week. Samples collected on weekends or holidays are held in Central Labs and sent to the Genomic Diagnostic Lab the following business day.
For External Clients: Refrigerate sample until shipment. Send the sample at room temperature with overnight delivery for receipt Monday through Friday, optimally within 24 hours of collection.
Please contact the lab (267-426-1447) with questions regarding non-blood specimens.
Volume Required
3-5 mL
Minimum Required
1 mL
Phlebotomy Draw
Yes
Performing Lab
Division of Genomic Diagnostics
Performed
Mon-Fri 9:00am - 4:00pm
Reported
10 days
Synonyms
TPMTS
LIS Mnemonic
TPMTS
Available STAT
No
Test Notes
PCR and Sequencing
Molecular Testing Notes
Mercaptopurine, a type of thiopurine drug, is the mainstay of curative therapy for acute lymphoblastic leukemia. To achieve its cytotoxic effects, thiopurines require extensive metabolism in the body. Patients with thiopurine methyltransferase (TPMT) deficiency experience severe hematologic toxicity when treated with standard
doses of MP. TMPT polymorphisms are most common in individuals of Hispanic descent, followed by Africans, Europeans, and East Asians.
Preemptive genotyping of TPMT allows identification of patients who are at risk for increased toxicity resulting from use of MP, so that the starting dose of MP can be appropriately adjusted, or an alternative therapy may be considered.
CPT Codes
81335
Billing (EAP) Codes
807137-TPMT, Genotype Known Mutation
Collection
Collect
Blood or bone marrow in a purple-top (EDTA) tube. Saliva is also acceptable.
Storage/Transport Temperature
For CHOP Phlebotomy: Samples can be collected throughout the week. Samples collected on weekends or holidays are held in Central Labs and sent to the Genomic Diagnostic Lab the following business day.
For External Clients: Refrigerate sample until shipment. Send the sample at room temperature with overnight delivery for receipt Monday through Friday, optimally within 24 hours of collection.
Please contact the lab (267-426-1447) with questions regarding non-blood specimens.
Volume Required
3-5 mL
Minimum Required
1 mL
Phlebotomy Draw
Yes
Ordering
Performing Lab
Division of Genomic Diagnostics
Performed
Mon-Fri 9:00am - 4:00pm
Reported
10 days
Synonyms
TPMTS
LIS Mnemonic
TPMTS
Available STAT
No
Test Notes
PCR and Sequencing
Molecular Testing Notes
Mercaptopurine, a type of thiopurine drug, is the mainstay of curative therapy for acute lymphoblastic leukemia. To achieve its cytotoxic effects, thiopurines require extensive metabolism in the body. Patients with thiopurine methyltransferase (TPMT) deficiency experience severe hematologic toxicity when treated with standard
doses of MP. TMPT polymorphisms are most common in individuals of Hispanic descent, followed by Africans, Europeans, and East Asians.
Preemptive genotyping of TPMT allows identification of patients who are at risk for increased toxicity resulting from use of MP, so that the starting dose of MP can be appropriately adjusted, or an alternative therapy may be considered.
