Mismatch Repair by Immunohistochemistry with Reflex to BRAF Mutation Detection with Reflex to MLH1 Promoter Methylation
Ordering Recommendation
Preferred screening test for Lynch syndrome (LS) in individuals with colorectal cancer. Definitive diagnosis of LS requires additional targeted germline mismatch repair gene testing. Do not use in endometrial cancer. If MLH1 is abnormal for Mismatch Repair by IHC, then BRAF Mutation Detection (3017204) will be added. If BRAF Mutation Detection is negative, MLH1 Promoter Methylation will be added.
New York DOH Approval Status
Specimen Required
Tumor tissue.
Tumor Tissue: Formalin fix (10 percent neutral buffered formalin is preferred) and paraffin embed tissue. If sending precut slides, do not oven bake. Transport tissue block or 15 unstained (3- to 5-micron thick sections), positively charged slides in a tissue transport kit (ARUP Supply #47808). Available online through eSupply using ARUP Connect(TM) or contact ARUP Client Services at 800-522-2787. (Min: 10 slides). Protect paraffin block and/or slides from excessive heat.
Room temperature. Also acceptable: Refrigerated. Ship in cooled container during summer months.
Paraffin block with less than 25 percent tumor tissue. Specimens fixed in any fixative other than 10 percent neutral buffered formalin. Decalcified specimens.
Include surgical pathology report. Submit electronic request. If you do not have electronic ordering capability, use an ARUP requisition form complete with an ARUP client number. For additional technical details, please contact ARUP Client Services at 800-522-2787.
If multiple specimens (blocks or slides) are sent to ARUP, they must be accompanied by one of the following: an order comment indicating that the ARUP pathologist should choose the specimen most appropriate for testing (e.g., "Choose best block"), or individual orders for each sample submitted. A Pathologist Block Selection Fee (ARUP test code 3002076) will be added to orders that utilize the first option. If multiple specimens are sent to ARUP without a request for pathologist block/slide selection or individual orders, they will be held until clarification is provided.
Ambient: Indefinitely; Refrigerated: Indefinitely; Frozen: Unacceptable
Methodology
Qualitative Immunohistochemistry (IHC)/Qualitative Real-Time Polymerase Chain Reaction
Performed
Mon-Fri
Reported
1-5 days
If reflexed, add 7-10 days.
Reference Interval
Interpretive Data
Refer to report.
Refer to the Colorectal Cancer or Lynch Syndrome topics at arupconsult.com.
Modified FDA
Note
If MLH1 is abnormal for mismatch repair by IHC, then BRAF Mutation Detection with Reflex to MLH1 Promoter Methylation (ARUP test code 3017204) will be added. If BRAF mutation detection is negative, MLH1 promoter methylation will be added. Additional charges apply.
Hotline History
Hotline History
CPT Codes
88342; 88341 x3; if reflexed, add 81210; if further reflexed, add 81288
Components
Component Test Code* | Component Chart Name | LOINC |
---|---|---|
0049199 | Client Case or Ref # | 94736-6 |
0049303 | Mismatch Repair by IHC, Result | 50595-8 |
0049305 | Mismatch Repair by IHC with MLH1 | 50322-7 |
0049310 | Mismatch Repair by IHC with MSH2 | 50323-5 |
0049320 | Mismatch Repair by IHC with MSH6 | 50324-3 |
0049325 | Mismatch Repair by IHC with PMS2 | 50328-4 |
3002969 | MSI Tissue Source | 31208-2 |
Aliases
- MSI
- MSI with BRAF, MLH1reflex
- MSI reflex to BRAF and MLH1 Methylation