Microsatellite Instability (MSI)

Test name:
MSI – Microsatellite Instability

Order name:
MSI

Specimen requirements:
Formalin-fixed paraffin embedded tissue (FFPE)

Minimum volume:
This test compares tumor DNA to normal DNA. Therefore, two tissue types must be submitted; slides containing tumor in addition to slides with normal tissue.
Tumor containing block: 5-10 10µm thickness unstained slides with stained H&E of same block.
Normal tissue block: 5-10 10µm thickness unstained slides with stained H&E of same block.

Storage and stability information:
Room temperature

Test performed:
Once per week

Methodology:
Polymerase Chain Reaction (PCR), Capillary Electrophoresis

Reference range:
MSI stable

Clinical significance:
The Microsatellite Instability assay is used to evaluate tumor tissue to identify patients at high risk for having HNPCC/Lynch syndrome. Tumor tissue is indirectly evaluated for the presence of defective DNA Mismatch repair by analyzing MSI (Microsatellite instability) patterns.

CPT codes:
81301