Ordering Recommendation

First-line screening test for Lynch syndrome.  

Mnemonic
MSI
Methodology

Qualitative Immunohistochemistry

Performed

Tue-Sat

Reported

Within 5 days

New York DOH Approval Status
This test is New York DOH approved.
Specimen Required
Patient Preparation
Collect

Tumor tissue.

Specimen Preparation

Formalin fix (10 percent neutral buffered formalin is preferred) and paraffin embed specimen. If sending precut slides, do not oven bake. Transport tissue block or 10 unstained (3-5 micron thick sections), positively charged slides in a tissue transport kit (ARUP supply #47808) available online through eSupply using ARUP Connect™ or contact ARUP Client Services at (800) 522-2787.(Min: 5 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

Frozen specimens. Specimens fixed or processed in alternative fixatives (alcohol, Prefer) or heavy metal fixatives (B-4 or B-5). Depleted or no tumor in tissue. Specimens submitted with non-representative tissue type. Decalcified specimens.

Remarks

Only tissue that is clearly carcinoma (established by histological criteria) should be tested. 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.

Stability

Ambient: Indefinitely; Refrigerated: Indefinitely; Frozen: Unacceptable

Reference Interval
Interpretive Data

Refer to report

Compliance Category

Laboratory Developed Test (LDT)

Note
Hotline History
N/A
CPT Codes

88342; 88341 x3

Components
Component Test Code* Component Chart Name LOINC
0049199 Client Case or Ref # 49581-2
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
* 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
  • MLH1 IHC
  • MMR IHC
  • MMR Immunostaining
  • MSH2 IHC
  • MSH6 IHC
  • MSI
  • MSI Antibody Immunostaining
  • MSI IHC
  • PMS2 IHC
Mismatch Repair by Immunohistochemistry