Mismatch Repair by Immunohistochemistry with Reflex to MLH1 Promoter Methylation
2005270
Ordering Recommendation
Preferred reflex screening test for LS in non-CRC tumors (eg, endometrial carcinoma) .
Mnemonic
MSI MLH1
Methodology
Qualitative Immunohistochemistry/Qualitative Real-time Polymerase Chain Reaction
Performed
Mon, Thu
Reported
Within 5 days
If the test reflexes, results will be available within 15 days.  
New York DOH Approval Status
This test is New York DOH approved.
Submit With Order
Specimen Required
Patient Preparation
  
Collect
Tumor tissue.  
Specimen Preparation
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 20 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: 15 slides). Protect paraffin block and/or slides from excessive heat.  
Storage/Transport Temperature
Room temperature or refrigerated. Ship in cooled container during summer months.  
Unacceptable Conditions
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.  
Remarks
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.  
Stability
Ambient: Indefinitely; Refrigerated: Indefinitely; Frozen: Unacceptable  
Reference Interval
   
Interpretive Data
Refer to report.

See Compliance Statement B: www.aruplab.com/CS  
Note
If MLH1 is abnormal for Mismatch Repair by IHC, then MLH1 Promoter Methylation will be added. Additional charges apply.
CPT Code(s)
88342 x4; if reflexed, add 88381, 81479
Components
Component Test Code*Component Chart Name
0049199Client Case or Ref #
0049305Mismatch Repair by IHC with MLH1
0049310Mismatch Repair by IHC with MSH2
0049320Mismatch Repair by IHC with MSH6
0049325Mismatch Repair by IHC with PMS2
2005503Mismatch Repair by IHC Result
* Component test codes cannot be used to order tests. The information provided here is not sufficient for interface builds; for a complete test mix, please click the sidebar link to access the Interface Map.
Aliases
  • Microsatellite Instability
  • MLH1 Promoter Methylation
  • MSI
  • MSI reflex to MLH1 Methylation