Dahl Chase Folders

Colorectal Carcinoma Molecular Analysis

Reference Number: AA-00436

Colorectal Carcinoma Molecular Analysis


Clinical Significance:

Recently established guidelines from the American Society for Clinical Pathology (ASCP), College of American Pathologists (CAP), Association for Molecular Pathology (AMP) and/or the American Society of Clinical Oncology (ASCP) recommend testing for all resected colorectal carcinomas or metastatic colorectal carcinomas and selected biopsy cases where resection will not be performed or available.  Colorectal carcinoma molecular analysis is a panel of the following molecular tests for the following:

  •         KRAS Mutation (codons 12, 13, 61, 117, and 146)
  •         NRAS Mutation (codons 12, 13, 61, 117, and 146)
  •         BRAF V600 Mutation Assay
  •         Microsatellite Instability (MSI), reflex to mismatch repair (MMR) deficiency (MLH1, MSH2, MSH6, PMS2) by Immunohistochemistry if MSI-H.
  •         HER2 gene amplification by FISH
  •         NTRK gene rearrangement by immunohistochemistry (IHC) with reflex of positive cases to confirmatory RNA-based NGS analysis.


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)



DNA isolation and extraction, library prep, fluorescent in-situ hybridization (FISH), immunohistochemistry (IHC), and next-generation sequencing (NGS)



Molecular pathology requisition form



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.


CPT codes:

88381, 81210, 81275, 81276x3, 81301, 81311, 81403x2, 88342, 88341x2, 88377, G0452

Test reported:

Results are reported within 7-10 days