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Test Code MSI Microsatellite Instability (MSI), Tumor

Useful For

Evaluation through comparison of both tumor and normal tissue to identify patients at high risk for having hereditary nonpolyposis colorectal cancer (HNPCC)/Lynch syndrome

 

Evaluation through comparison of both tumor and normal tissue for clinical decision-making purposes given the prognostic implications associated with MSI phenotypes

Additional Tests

Test ID Reporting Name Available Separately Always Performed
SLIRV Slide Review in MG No, (Bill Only) Yes

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.

Method Name

A polymerase chain reaction (PCR)-based assay is used to test for tumor microsatellite instability with the use of 5 mononucleotide repeats.

Reporting Name

Microsatellite Instability, Tumor

Specimen Type

Varies


Advisory Information


 



Shipping Instructions


Ambient specimen preferred to arrive within 96 hours of draw.



Necessary Information


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



Specimen Required


This test cannot be used to assess tumor tissue unless both tumor and normal tissue are submitted.

 

If sending multiple blocks, identify individual blocks as normal or tumor.

 

Paraffin-embedded tissue blocks that have been decalcified are generally unsuccessful and not validated for testing. If a decalcified specimen is submitted (regardless of decal solution), testing will be canceled.

 

Specimen Type: Tumor tissue block, formalin-fixed, paraffin-embedded (FFPE) prepared cell block unstained slides

Specimen Volume: Approximately 1 cm(2) of tumor is required. This can be 1 cm(2) in aggregate (eg, 5 unstained slides each containing with 0.2 cm(2) of tumor and normal tissue).


Collection Instructions:

1. Submit formalin-fixed, paraffin-embedded tissue block with corresponding hematoxylin and eosin (H and E) slides (preferred) or 1 slide stained with H and E and 10 unstained, nonbaked slides (5- micrometer thick sections) of the tumor tissue.

2. Label specimen as Tumor.

 

Specimen Type: Normal tissue block or slide

Specimen Volume: Approximately 1 cm(2) of normal tissue is required. This can be 1 cm(2) in aggregate (eg, 5 unstained slides each with 0.2 cm(2) of normal tissue)

Collection Instructions:

1. Submit formalin-fixed, paraffin-embedded tissue block with corresponding hematoxylin and eosin (H and E) slides (preferred) or 1 slide stained with H and E and 10 unstained, nonbaked slides (5- micrometer thick sections) of the normal tissue.

2. Label specimen as Normal.

Additional Information:

1. Normal tissue does not have to be from the same specimen or tissue source as the tumor specimen submitted for testing. Any normal tissue block, with the exception of tissues composed primarily of adipose tissue, may be submitted. Specimens composed primarily of adipose tissue would not yield a sufficient amount of DNA and if submitted, testing will be canceled.

2. If normal tissue in a formalin-fixed, paraffin-embedded tissue block is not available, whole blood may be submitted instead (see below). A separate FFPE-tumor block is still required for testing if sending in a whole blood specimen for normal.

 

Specimen Type: Normal whole blood (if normal tissue block is not available)

Container/Tube: Lavender-top (EDTA) or yellow-top (ACD)

Acceptable: Any anticoagulant

Specimen Volume: 3 mL

Collection Instructions:

1. Invert several times to mix blood.

2. Send specimen in original tube.

3. Label specimen as Normal.


Specimen 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

Monday, Wednesday; 2 p.m.

Performing Laboratory

Mayo Clinic Laboratories in Rochester

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-Microsatellite instability analysis (eg, hereditary non-polyposis colorectal cancer, Lynch syndrome) of markers for mismatch repair deficiency (eg, BAT25, BAT26), includes comparison of neoplastic and normal tissue, if performed

88381-Microdissection, manual

LOINC Code Information

Test ID Test Order Name Order LOINC Value
MSI Microsatellite Instability, Tumor 43368-0

 

Result ID Test Result Name Result LOINC Value
53306 Result Summary 50397-9
53307 Result 43368-0
53308 Interpretation 69047-9
53309 Specimen 31208-2
53310 Source 31208-2
54448 Tissue ID 80398-1
53311 Released By 18771-6

Forms

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

2. If not ordering electronically, complete, print, and send 1 of the following forms with the specimen:

-Oncology Test Request (T729)

-Gastroenterology and Hepatology Client Test Request (T728)