Test Catalog

Test ID: TMSI    
Microsatellite Instability, Tumor

Testing Algorithm Delineates situations when tests are added to the initial order. This includes reflex and additional tests.

When this test is ordered, slide review will always be performed at an additional charge.


See Lynch Syndrome Testing Algorithm in Special Instructions.

Specimen Type Describes the specimen type validated for testing


Necessary Information

Pathology report must accompany specimen in order for testing to be performed.

Specimen Required Defines the optimal specimen required to perform the test and the preferred volume to complete testing

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



Specimen Type: Tissue block

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



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.

Special Instructions Library of PDFs including pertinent information and forms related to the test


1. Molecular Genetics: Inherited Cancer Syndromes Patient Information (T519) in Special Instructions.

2. If not ordering electronically, complete, print, and send a Gastroenterology and Hepatology Client Test Request (T728) with the specimen.

Reject Due To Identifies specimen types and conditions that may cause the specimen to be rejected

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

Specimen Stability Information Provides a description of the temperatures required to transport a specimen to the performing laboratory, alternate acceptable temperatures are also included

Specimen TypeTemperatureTimeSpecial Container
VariesAmbient (preferred)