Mismatch Repair by Immunohistochemistry with Reflex to MLH1 Promoter Methylation
Preferred reflex screening test for Lynch syndrome in non-colorectal cancer tumors (eg, endometrial carcinoma).
Qualitative Immunohistochemistry/Qualitative Real-time Polymerase Chain Reaction
Within 5 days
If the test reflexes, results will be available within 15 days.
New York DOH Approval Status
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 (3-5 micron thick sections), positively charged slides in a tissue transport kit (ARUP supply #47808). Available online through eSupply using ARUP ConnectTM or contact ARUP Client Services at (800) 522-2787. (Min: 7 slides). Protect paraffin block and/or slides from excessive heat.
Room temperature or refrigerated. Ship in cooled container during summer months.
Less than 25 percent tumor. Specimens fixed or processed in alternative fixatives (alcohol, Prefer) or heavy metal fixatives (B-4 or B-5). Depleted or no tumor in tissue. 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, 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
Refer to report.
This test was developed and its performance characteristics determined by ARUP Laboratories. It has not been cleared or approved by the US Food and Drug Administration. This test was performed in a CLIA certified laboratory and is intended for clinical purposes.
Laboratory Developed Test (LDT)
If MLH1 is abnormal for Mismatch Repair by IHC, then MLH1 Promoter Methylation will be added. Additional charges apply.
88342; 88341 x3; if reflexed, add 81288; 88381
|Component Test Code*||Component Chart Name||LOINC|
|0049199||Client Case or Ref #||49581-2|
|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|
|2005503||Mismatch Repair by IHC Result|
|3002969||MSI Tissue Source|
- Microsatellite Instability
- MLH1 Promoter Methylation
- MSI reflex to MLH1 Methylation