Microsatellite Instability, Tumor

Alphabetical Test listing

Microsatellite Instability, Tumor-Pathology add-on

Test name:

Test number:

Pathology add-on

Abbreviation:

MSI

Alternate names:

DNA Mismatch Repair-related HNPCC
Hereditary Nonpolyposis Colon Cancer (HNPCC)
Lynch syndrome
Lynch
Microsatellite Instability
MSI
Tumor microsatellite Instability
MMR
Mismatch repair
Mismatch repair deficiency

Useful for:

Evaluation of tumor tissue to identify patients at high risk for having Lynch syndrome, also known as hereditary nonpolyposis colorectal cancer.

Evaluation of tumor tissue for clinical decision-making purposes given the prognostic and therapeutic implications associated with microsatellite instability phenotypes

Specimen type:

Tissue Block

Volume:

Preferred amount of tumor area with sufficient percent tumor nuclei: tissue 72 mm(2)

Minimum volume:

Minimum amount of tumor area: 18 mm(2) (at least 40% tumor nuclei for endometrial specimens and at least 20% tumor nuclei for colorectal specimens)

Collection instructions:

Submit a formalin-fixed, paraffin-embedded tissue block with acceptable amount of tumor tissue.

Transport container:

Formalin-fixed, paraffin-embedded (FFPE) tissue block

Alternate specimen type:

Tissue Slide

Alternate collection container:

1 stained and 5 unstained slides

Alternate collection instructions:

Submit 1 slide stained with hematoxylin and eosin and 5 unstained, nonbaked slides with 5-micron thick sections of the tumor tissue.

Required forms/information:

Molecular Medicare billing request

Hospital clients submitting a request for this assay on an outpatient with Medicare should complete and submit a Molecular Medicare billing request form to notify us of the need for Allina Health Laboratory to bill insurance.

Molecular Genetics: Inherited Cancer Syndromes Patient Information

Complete and submit the form
All information requested is required in order for your request to be completed

Transport and stability:

Ambient

Reason for rejection:

Decalcified specimens
Low tumor percentage
Insufficient amount of tumor
Nonformalin-fixed
Fresh tissue
Cytology smears

Performing lab:

Mayo Clinic Laboratories (TMSI): R-NX

Days set up:

Mo -Fr

TAT:

2 - 5 days

Method:

Polymerase Chain Reaction (PCR)

Preauthorization:

This test may require preauthorization from the insurance provider. Check the payer guidelines and, if needed, obtain the pre-authorization prior to sample collection.

CPT codes:

81301
88381 - Microdissection, manual

Subject to medical necessity (Y/N):

Yes

Other billing information:

Medical necessity

Molecular Medicare billing request

Date created:

05/08/2023

Revised date:

05/23/2024

Review date:

07/11/2023