ARUP's Laboratory Test Directory

Mismatch Repair by Immunohistochemistry with Reflex to MLH1 Promoter Methylation : 2005270
[ image for: Additional Technical Information]
Additional Technical Information
  


Mnemonic: MSI MLH1

Ordering Recommendation: Preferred primary test to distinguish between sporadic and Lynch associated microsatellite unstable (MSI) noncolorectal cancer. Distinguish sporadic versus inherited Lynch syndrome in colorectal cancer; preferred reflex test is Mismatch Repair by Immunohistochemistry with Reflex to BRAF Codon 600 Mutation and MLH1 Promoter Methylation (2002327).
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.
Specimen Required: 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.

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.

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.

Stability (collection to initiation of testing): Ambient: Indefinitely; Refrigerated: Indefinitely; Frozen: Unacceptable
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 (4); if reflexed, add 88381, 81479, G0452
Cross References: Endometrial Cancer (Mismatch Repair by Immunohistochemistry with Reflex to MLH1 Promoter Methylation) , HNPCC/Lynch Syndrome (Mismatch Repair by Immunohistochemistry with Reflex to MLH1 Promoter Methylation) , Lynch Syndrome/Microsatellite Instability (Mismatch Repair by Immunohistochemistry with Reflex to MLH1 Promoter Methylation) , Microsatellite Instability (Mismatch Repair by Immunohistochemistry with Reflex to MLH1 Promoter Methylation) , MSI (Mismatch Repair by Immunohistochemistry with Reflex to MLH1 Promoter Methylation)