Ordering Recommendation

First-line screening test for Lynch syndrome. 

New York DOH Approval Status

This test is New York state 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(TM) 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 nonrepresentative 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. 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.

Stability

Ambient: Indefinitely; Refrigerated: Indefinitely; Frozen: Unacceptable

Methodology

Qualitative Immunohistochemistry

Performed

Mon-Fri

Reported

1-3 days

Reference Interval

Interpretive Data



Compliance Category

Laboratory Developed Test (LDT)

Note

This orderable is offered as a panel only. Individual MLH1, MSH2, MSH6, and PMS2 IHC stains are not offered at this time.

This orderable is performed as a stain and return (technical) service only. Please refer to ARUP test code 0049302 if ARUP pathologist interpretation is needed.

Hotline History

N/A

CPT Codes

88342/88341x3

Components

Component Test Code* Component Chart Name LOINC
3017883 SO MSI Panel by IHC
3017884 SO MSI Reference Number
* 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 Panel by Immunohistochemistry