Figure 2. Droplet digital PCR maintains linearity over a broad copy number range.

(A) Schematic representation of the 70-nucleotide double-stranded synthetic MYCN template covering the complete sequence of the MYCN amplicon. Primers (arrows), probe (green line) and the positions of the FAM fluorescent dye (green dot) and BHQ1 quencher (black dot) are indicated. (B) Theoretically calculated numbers of MYCN copies after serial dilution of the synthetic template in H₂O are shown. (C) Correlation analysis of theoretically calculated MYCN copies (x-axis) and copies of synthetic template assessed in dilution series using ddPCR (y-axis, as mean ± SD; n ≥ 3). Pearson’s correlation coefficient (r) and p-value is indicated.