Clinical Significance:
The American Society of Clinical Oncologists (ASCO), ASCP, CAP, AMP, and National Comprehensive Cancer Network (NCCN) recommend routine testing for RAS mutation at diagnosis of stage IV disease and all colorectal carcinomas considered for therapy with cetuximab or panitumumab, either alone or in combination with other anti-cancer agents.

https://www.nccn.org/professionals/physician_gls/pdf/colon.pdf

Specimen Requirements and Collection:
Formalin fixed tissue containing a sufficient amount of tumor (generally at least several mm of tumor tissue submitted in the tissue block).  The KRAS test utilized by our laboratory will detect mutations as long as they constitute at least 10% of the DNA sample population.

Methodology:
DNA isolation and extraction, library prep, and next-generation sequencing (NGS) for hotspot mutations KRAS exon 2, 3, and 4

Forms:
Molecular Pathology requisition form

Transport:
Send formalin-fixed, paraffin-embedded (FFPE) tissue and cell block containing tumor at room temperature.  Also acceptable 10-unstained, 4-5 micron slides with 1 post H&E.  Please include a surgical pathology report

Unacceptable specimen:
Specimens fixed in alternative fixatives or metal fixatives (ex. B-plus).  Decalcified specimens.

Reference Range:
KRAS mutation not detected = negative result
KRAS mutation detected = positive result

CPT codes:
88381, 81275, 81276, 81403, G0452

Test reported:
Results are reported within 7-10 days