By Dianna Maar, Nicholas J. Heredia, and Shawn Hodges , Bio-Rad Laboratories
Droplet Digital PCR (ddPCR) enables easy multiplexing of numerous targets within each fluorescent channel. Multiplexing with Droplet Digital PCR allows for improved sensitivity and precision, as well as increased low-level detection in limited sample types like liquid biopsies. This is especially useful for increasing the sensitivity when detecting somatic mutations, edits, viruses, and other very rare targets. Multiple targets can be measured simultaneously by creating a unique endpoint fluorescence for each target. Amplitude-based multiplexing achieves this by varying primer and/or probe concentrations. In probe-mixing multiplexing, probes are mixed at desired concentrations to place targets in a defined position on a 2-D plot. This paper describes strategies for both approaches using the large portfolio of ddPCR Assays readily available through Bio‑Rad.