Note: Digital PCR is a new alternate method to conventional real-time PCR and quantitative PCR for absolute quantification and rare allele detection. Digital PCR works by partitioning a sample of deoxyribonucleic acid (DNA) or complementary DNA into many individual, parallel PCR reactions; some of these reactions contain the target molecule (complementary DNA, positive) while others do not (negative). A single molecule can be amplified a million-fold or more.