Ordering Recommendation

First-line screening test for Lynch syndrome.  


Qualitative Immunohistochemistry




Within 5 days

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

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.


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.


Ambient: Indefinitely; Refrigerated: Indefinitely; Frozen: Unacceptable

Reference Interval
Interpretive Data

Refer to report

Compliance Statement B: For laboratory developed tests not using a RUO kit, and for FDA approved, cleared or 510(k) exempt assays with alterations. This test was developed and its performance characteristics determined by ARUP Laboratories. The U. S. Food and Drug Administration has not approved or cleared this test; however, FDA clearance or approval is not currently required for clinical use. The results are not intended to be used as the sole means for clinical diagnosis or patient management decisions.

Hotline History
CPT Codes

88342; 88341 x3

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
* 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.
  • MLH1 IHC
  • MMR Immunostaining
  • MSH2 IHC
  • MSH6 IHC
  • MSI
  • MSI Antibody Immunostaining
  • PMS2 IHC
Mismatch Repair by Immunohistochemistry