Microsatellites are regions of DNA repeats with different lengths, i.e., instability, highlighting DNA mismatch repair gene deficiencies. Typical repeat units are between 1-6 base pairs and the number of repeats vary from person to person such that each person has a set length of these microsatellites in their genome. Measurements of MSI have traditionally been performed using qPCR/CE fragment length analysis methods, or immunohistochemistry (IHC), but new methodologies such as digital droplet PCR (ddPCR) and Next Generation Sequencing (NGS) are now being applied to determination of MSI status of cancer patients. High incidence of microsatellite instability (MSI) has been linked to favorable outcomes in immuno-oncology (I-O) treatment response by patients with diseases such as Lynch Syndrome and colorectal cancer. Hence determination of MSI status for cancer patients is important in I-O therapeutics management.