Microsatellite Instability (MSI) HNPCC/Lynch Syndrome by PCR

Casandra

Casandra Test Code AR93775Version 1 (DRAFT)

Performing Lab

Lab ARUP LaboratoriesLab Test ID 3004277CPT Code 81301

Microsatellite Instability (MSI) HNPCC/Lynch Syndrome by PCR

Also known as: MSIPCR

Clinical Use

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Use

This test is a screening tool for Lynch syndrome, also known as Hereditary Nonpolyposis Colorectal Cancer (HNPCC). It helps in determining potential eligibility for immunotherapy by identifying microsatellite instability-high (MSI-H) cancers, which often occur in colorectal cancer from individuals with Lynch syndrome and sporadically in some cancers. For specific treatment recommendations, reference is made to the NCCN Clinical Practice Guidelines in Oncology.

Special Instructions

Not provided.

Limitations

The test only detects microsatellite instability at markers BAT-25, BAT-26, MONO-27, NR-21, and NR-24. Instability at other loci will not be detected. The findings must be interpreted in the clinical context and are not definitive for malignancy diagnosis. It does not rule out other genetic disorders associated with colorectal cancer. Genetic counseling is recommended.

Test Details

New York Approved

Methodology

PCR-based (PCR)

Biomarkers

5 targets

BAT-25BAT-26MONO-27NR-21NR-24

LOINC Codes

Result Codes

81697-5 - MSI mark BAT25 Ca spec Ql
81698-3 - MSI mark BAT26 Ca spec Ql
81701-5 - MSI mark MONO27 Ca spec Ql
43368-0 - MSI Tiss
81699-1 - MSI mark NR21 Ca spec Ql
81700-7 - MSI mark NR24 Ca spec Ql

Result Turnaround Time

10-20 days

Specimen

Tissue (FFPE)

Volume

Not provided

Minimum Volume

Not provided

Collection Instructions

Formalin fix tissue (10 percent neutral buffered formalin) and paraffin embed. Transport tissue block(s) or 10 unstained 5-micron slides (5 tumor and 5 normal epithelial) in a tissue transport kit.

Storage Instructions

Room temperature is preferable, but refrigerated is acceptable. Transport in a cooled container during summer months.

Causes for Rejection

Specimens with less than 25 percent tumor or less than 50 percent normal epithelial tissue. Specimens fixed in fixatives other than 10 percent neutral buffered formalin or bone specimens in non-EDTA decalcifier.