Test ID TMSI Microsatellite Instability, Tumor
Shipping Instructions
Necessary Information
Pathology report must accompany specimen in order for testing to be performed.
Specimen Required
This assay requires at least 40% tumor nuclei for endometrial specimens and at least 20% tumor nuclei for colorectal specimens
-Preferred amount of tumor area with sufficient percent tumor nuclei: tissue 72 mm(2)
-Minimum amount of tumor area: 18 mm(2)
-These amounts are cumulative over up to 10 unstained slides and must have adequate percent tumor nuclei.
-Tissue fixation: formalin-fixed paraffin-embedded (FFPE), non-decalcified
Preferred:
Specimen Type: Tissue block
Collection Instructions: Submit a formalin-fixed, paraffin-embedded tissue block with acceptable amount of tumor tissue.
Acceptable:
Specimen Type: Tissue slide
Slides: 1 stained and 5 unstained
Collection Instructions: Submit 1 slide stained with hematoxylin and eosin and 5 unstained, nonbaked slides with 5-micron thick sections of the tumor tissue.
Note: The total amount of required tumor nuclei can be obtained by scraping up to 5 slides from the same block.
Forms
Molecular Genetics: Inherited Cancer Syndromes Patient Information (T519) in Special Instructions
Useful For
Evaluation of tumor tissue to identify patients at high risk for having Lynch syndrome, also known as hereditary nonpolyposis colorectal cancer (HNPCC)
Evaluation of tumor tissue for clinical decision-making purposes given the prognostic and therapeutic implications associated with microsatellite instability phenotypes
Testing Algorithm
When this test is ordered, slide review will always be performed at an additional charge.
See Lynch Syndrome Testing Algorithm in Special Instructions.
Special Instructions
Method Name
Polymerase Chain Reaction (PCR)
Reporting Name
Tumor, Microsatellite InstabilitySpecimen Type
VariesSpecimen Stability Information
Specimen Type | Temperature | Time | Special Container |
---|---|---|---|
Varies | Ambient (preferred) | ||
Frozen | |||
Refrigerated |
Reference Values
An interpretive report will be provided.
Day(s) and Time(s) Performed
Daily; Varies
Performing Laboratory

Test Classification
This test was developed and its performance characteristics determined by Mayo Clinic in a manner consistent with CLIA requirements. This test has not been cleared or approved by the U.S. Food and Drug Administration.CPT Code Information
81301
88381-Microdissection, manual
LOINC Code Information
Test ID | Test Order Name | Order LOINC Value |
---|---|---|
TMSI | Tumor, Microsatellite Instability | In Process |
Result ID | Test Result Name | Result LOINC Value |
---|---|---|
609365 | Result Summary | 50397-9 |
609366 | Result | 43368-0 |
609367 | Interpretation | 69047-9 |
609368 | Specimen | 31208-2 |
609369 | Source | 31208-2 |
609370 | Tissue ID | 80398-1 |
609371 | Released By | 18771-6 |
NY State Approved
YesAdditional Tests
Test ID | Reporting Name | Available Separately | Always Performed |
---|---|---|---|
SLIRV | Slide Review in MG | No, (Bill only) | Yes |