The concept of digital PCR was first described in 1992 by Sykes et al., who recognized that the combination of limiting dilution, end-point PCR, and Poisson statistics could yield an absolute measure of nucleic acid concentration (Sykes et al. 1992). Subsequently, Vogelstein and Kinzler at Johns Hopkins University developed a method whereby a sample can be diluted and partitioned to the extent that single template molecules can be amplified individually, each in a separate partition, and the products detected using fluorescent probes (Vogelstein and Kinzler 1999). This approach transformed qPCR into digital-format qPCR because the results are binary — either positive or negative — and thus the new term “digital PCR” was coined for this generation of PCR methods.