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Specimen Collection Manual and Test Catalog

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C-KIT MUTATIONS WITH REFLEX TO PDGFRA MUTATIONS FOR GIST

Geisinger Epic Procedure Code:  LAB1239    Geisinger Epic ID:  52881

SPECIMEN COLLECTION
Specimen type: 

Formalin-fixed, paraffin-embedded tissue block (preferred) or whole blood or bone marrow


Preferred collection container: 
Alternate collection container: 
3 mL lavender-top (K2 EDTA) tube
Specimen required: 

Formalin-fixed, paraffin-embedded tissue block (preferred) OR 6 mL whole blood; minimum 4 mL OR 3 mL bone marrow; minimum 1 mL


Special notes: 

After collection of the sample, draw date and time, as well as sample type, must be written on the tube and included as requested information.



SPECIMEN PROCESSING
Transport temperature: 

Tissue block: Room temperature. 
Whole blood or bone marrow: Refrigerated (cold packs). Do not freeze whole blood or bone marrow. 


Specimen stability: 

Tissue block: Room temperature: Indefinitely. Refrigerated: Indefinitely. Frozen: Unacceptable. 
Whole blood or bone marrow: Room temperature: 7 days. Refrigerated: 14 days. Frozen: Unacceptable.


Rejection criteria: 

Gross hemolysis • Clotted or frozen whole blood • Clotted or frozen bone marrow



TEST DETAILS
Additional information: 

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.


CPT code(s):  81272
Note: The billing party has sole responsibility for CPT coding.  Any questions regarding coding should be directed to the payer being billed.
The CPT codes provided by GML are based on AMA guidelines and are for informational purposes only.

Test includes: 

c-KIT Mutation Analysis, Cell-based; PDGFRA Mutation Analysis. If C-KIT Mutation, Cell-based result is Not detected, PDGFRA Mutation Analysis will be performed at an additional charge (CPT code(s): 81314).


Methodology: 
Polymerase Chain Reaction (PCR)
Sequencing
Synonyms: 

Quest test code 16237, cKIT PDGFRA


Clinical significance: 

Eighty percent of patients with gastrointestinal stromal tumor (GIST) have a C-KIT mutation in exon 9, 11, 13, or 17. The presence of a mutation usually predicts poor survival. Patients with C-KIT mutations other than D816V are likely to respond to imatinib (Gleevec) therapy. Mutations in the PDGFRA gene are found in about 7% of gastrointestinal stromal tumors (GISTs), especially in KIT wild type GISTs. PDGFRA mutations also have been described in synovial sarcomas (SSs) and malignant peripheral nerve sheath tumors (MPNST). GISTs with PDGFRA mutations (except D842V) are likely to respond to imatinib.


Review Date:  12/11/2024

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