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 Medical billing request form along with the sample.

Complete and submit the form to notify us of the need for Allina Health Laboratory to bill insurance for Molecular testing performed
All information requested is required in order for your request to be completed

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

Hospital clients submitting a request for this assay on an outpatient with Medicare should complete and submit a Molecular Medical billing request form along with the sample.

Complete and submit the form to notify us of the need for Allina Health Laboratory to bill insurance for Molecular testing performed
All information requested is required in order for your request to be completed

Molecular Medicare billing request

Date created:

05/08/2023

Revised date:

07/11/2023

Review date:

07/11/2023