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Colorectal Cancer – Microsatellite Instability by PCR

Detects instability of microsatellite loci associated with a loss or suppression of DNA mismatch repair system. Detects instability in 5 mononucleotide markers.

CPT Codes:

83891(2), 83900(1), 83901(8), 83907(1), 83909(2), 83912-26(1), 88381(1)


Specimen Requirements:

Please Note: This assay requires submission of normal tissue (normal colonic mucosa or normal tissue from other sites of the same patient or patient’s peripheral blood sample) for comparison with tumor.

  1. Peripheral Blood (for control for MSI):
    • 10-20 ml in EDTA (lavender-top) tube.
    • Refrigerate specimen. Use cold pack for transport. Be sure cold pack is not in direct contact with specimen during transport.
  2. Fixed Paraffin Block with Corresponding H&E:
    • Tissue should be well-fixed in formalin. If alternative fixative is used, it should be noted on the requisition. Average tissue size 5 mm.
    • 0.2 cm x 0.2 cm x 0.2 cm tissue.
    • Store specimen at room temperature (20-23.5° C).
    • Use cold pack for transport. Be sure cold pack is not in direct contact with specimen during transport.
  3. Precut 5-10 Slides of Microsections from Each Paraffin Block Submitted
    • Send all slides within 6 weeks of cutting.
    • Precut slides from paraffin blocks in 7 micron sections.
    • Mount on uncoated slides.
    • Air dry. Do not oven dry.
    • Store specimen at room temperature (20-23.5° C).

Turnaround Time:

6-7 days


Client Services: Oncology/Pathology   800-447-5816

Specimen Services/Pickup:  877-246-1226