Mismatch Repair Assessment (MMR-IHC) with Reflex to MSI Testing
| Label Mnemonic: | MMR |
| Epic code: | LAB8680 |
| Order form: | Molecular Oncology Requisition |
| Supply order: | Supply Order Form |
| Billing: | Billing Policies |
| CPT code: | "MLH-1, Immunostain" - 88341, 88342 (if appropriate) "MSH-2, Immunostain" - 88341, 88342 (if appropriate) "MSH-6, Immunostain" - 88341, 88342 (if appropriate) "PMS-2, Immunostain" - 88341, 88342 (if appropriate) "MSI, PCR" - 81301 |
Specimen(s):
Tumor
Collection Medium:
) |
| Tissue Block |
Turn Around
Time:
Within 5 days upon receipt
Reference Range:
An interpretive report will be provided.
Comments:
Mismatch repair protein immunohistochemistry is useful to screen for
Lynch syndrome and to determine the functional status of the DNA
mismatch repair apparatus.
A normal result argues against the presence of Lynch syndrome and indicates with a high degree of specificity that the tumor has proficient mismatch repair function.
Microsatellite instability testing is complementary and may be used to confirm a normal result. Depending on the pattern of staining with an abnormal result, additional testing and/or genetic counseling may be indicated.
Test results should be interpreted in the context of clinical findings, family history, and other laboratory data. Errors may occur in our interpretation of results if information given to us is inaccurate or incomplete
A normal result argues against the presence of Lynch syndrome and indicates with a high degree of specificity that the tumor has proficient mismatch repair function.
Microsatellite instability testing is complementary and may be used to confirm a normal result. Depending on the pattern of staining with an abnormal result, additional testing and/or genetic counseling may be indicated.
Test results should be interpreted in the context of clinical findings, family history, and other laboratory data. Errors may occur in our interpretation of results if information given to us is inaccurate or incomplete
Methodology:
Immunohistochemical staining is used to determine the presence or
absence of protein expression for MLH1, MSH2, MSH6, and PMS2.
Instructions:
Tumor tissue is required for this test. Pathology report MUST accompany the
specimen.
Send formalin-fixed, paraffin-embedded tissue block (preferred) or 1 slide stained with hematoxylin-and-eosin and 10 unstained, nonbaked slides (5 slides with 5-um thick sections) of the tumor tissue.
Send formalin-fixed, paraffin-embedded tissue block (preferred) or 1 slide stained with hematoxylin-and-eosin and 10 unstained, nonbaked slides (5 slides with 5-um thick sections) of the tumor tissue.
Transport
Instructions:
Protect block or slides from excessive heat and ship in cooled container during summer months.
CPT Code:
"MLH-1, Immunostain" - 88341, 88342 (if appropriate)
"MSH-2, Immunostain" - 88341, 88342 (if appropriate)
"MSH-6, Immunostain" - 88341, 88342 (if appropriate)
"PMS-2, Immunostain" - 88341, 88342 (if appropriate)
"MSI, PCR" - 81301
"MSH-2, Immunostain" - 88341, 88342 (if appropriate)
"MSH-6, Immunostain" - 88341, 88342 (if appropriate)
"PMS-2, Immunostain" - 88341, 88342 (if appropriate)
"MSI, PCR" - 81301