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Beaumont Laboratory

Mismatch Repair Mechanism (MMR) by Immunohistochemistry

MMR for Colon Cancer, Immunohistochemistry for Colon Cancer

Specimen Collection Criteria

Collect: Paraffin-embedded tissue. A paraffin block must be submitted. Submit formalin-fixed, paraffin-embedded block with corresponding H&E slide. Tissue should be well fixed and well processed. Average tissue size 5.0 mm2.

The specimen must be accompanied by a completed requisition and must contain the patient name, date of birth, collection date, ordering physician, and source of specimen.   

Physician Office/Drawsite Specimen Preparation

Maintain paraffin-embedded tissue at room temperature (20-26°C or 68-78.8°F) until transport.

Preparation for Courier Transport

Transport: Paraffin-embedded tissue, at room temperature (20-26°C or 68-78.8°F).

Rejection Criteria

  • Tissue in fixatives other than 10% formalin or zinc formalin.
  • Improper labeling, inadequate information.


Specimen Stability for Testing:

Room Temperature (20-26°C or 68-78.8°F): Indefinitely
Refrigerated (2-8°C or 36-46°F): Unacceptable
Frozen (-20°C/-4°F or below): Unacceptable

Specimen Storage in Department Prior to Disposal:

Room Temperature (20-26°C or 68-78.8°F): 7 days


Royal Oak Anatomic Pathology - Advanced Diagnostics Laboratory.


Monday - Friday.
Results available in 10 business days.

Reference Range

An interpretive report will be provided.

Test Methodology

Tissue sections are stained with four antibodies (MLH1, MSH2, MSH6, and PMS2) by immunohistochemistry.


An interpretive report will be provided.

Clinical Utility

Loss of protein expression is associated with loss or suppression of DNA mismatch repair complex.

CPT Code

88341x3, 88342.

Last Updated


Microtainer® and Vacutainer® are registered trademarks of Becton, Dickinson and Company.
UroVysion® is a registered trademark of Abbott Laboratories. ThinPrep® is a registered trademark of Hologic, Incorporated.

This directory currently reflects information only for specimens collected and/or processed at the Farmington Hills, Grosse Pointe, Royal Oak, and Troy campuses.