Microsatellite Instability Analysis (MSI) in Tumors


For determining microsatellite instability analysis (MSI) in colorectal and endometrial carcinomas for outcome predication and assessment of possibility hereditary contributions due to germline mutations in mismatch repair (MMR) genes. Tumors developing due to mutations in these genes exhibit instability of nucleotide repeats in microsatellites, which are short tandem repeat sequences distributed throughout the genome.


A total of 7 markers including a panel of 5 markers (BAT25, BAT26, D2S123, D5S346, D17S250) recommended by the National Cancer Institute (NCI) and, 2 additional markers (TGFβRII and BAT40) are tested. Fluorescently labeled primers are used in a multiplex PCR assay. Tumor and normal tissues from each patient are analyzed in parallel.

Test Parameters

The careful selection of an involved tumor sample and normal (uninvolved) sample is essential for appropriate interpretation of results.

Turnaround Time

Seven to 10 days

Sample Requirements

Sections of microdissected, paraffin-embedded tissue fixed on five to six slides, with areas of normal tissue and tumor clearly indicated. Please contact our laboratory for more information on submission requirements for this test.

Please provide a copy of the corresponding pathology report.

CPT Codes


Additional charges may apply for tissue extraction.

The CPT codes provided are based on AMA guidelines and are for informational purposes only. CPT coding is the sole responsibility of the billing party. Please direct any questions regarding coding to the payer being billed.