A Breakthrough in Quantitative PCR
The QX100™ Droplet Digital™ PCR (ddPCR™) system is the third generation of PCR technology. The QX100 ddPCR system provides an absolute measure of target DNA molecules for quantitative PCR applications, such as copy number variation, rare sequence detection, mutation detection, and gene expression analysis. The QX100 ddPCR system provides single copy PCR resolution to accelerate discoveries and new strategies for the research of inherited disorders, cancer, and infectious diseases.

A Simple, Elegant Workflow
The QX100 droplet generator partitions samples into thousands of nanoliter-sized droplets. After PCR on a thermal cycler, droplets from every sample are streamed in single file on the QX100 droplet reader to count positive and negative reactions. The PCR-positive and PCR-negative droplets are counted to provide absolute quantification in digital form.

The high precision, accuracy, and sensitivity of Droplet Digital PCR can be applied to a range of applications, including copy number variation (CNV) and rare mutation detection. The following data illustrate the performance of Bio-Rad's QX100™ Droplet Digital™ PCR (ddPCR™) system.

Copy Number Variation Data
The QX100 ddPCR system provides high resolution between copy number states and allelic discrimination. The ddPCR system's CNV data are shown to help validate next generation genome sequencing data.

Calculation of copy number variation. A, for MRGPRX1, the copy number states from 1 to 6 were completely resolved. B, SMN1 and SMN2 copy number estimation is plotted in two dimensions where each point represents an individual sample. The allelic discrimination 5' nuclease assays for SMN1 and SMN2 allow researchers to count genes that differ by only one nucleotide. C, CCL3L1 gene copy number determination on 19 samples demonstrates the accuracy and precision of ddPCR. The data demonstrate that copy number measurements cluster on integers up to 13 copies. Results validate previous next generation genome sequencing data, indicating 5.7 copies for NA18507.** Samples were obtained from the Coriell Institute. All error bars represent 95% Poisson confidence intervals (CIs).

Rare Mutation Detection Data
The QX100 ddPCR system offers high sensitivity and displays the ability to measure the varying degrees of a cell line mutagenesis.

Duplex PCR using TaqMan probes targeting the BRAF V600E mutation. The data show ddPCR detects a 0.001% mutant fraction. AU, absorbance units.

Gene Expression Analysis Data
The QX100 ddPCR system enables gene expression analysis with ±10% precision.

The data show a dilution series of two mRNAs. β-actin (); ANP32B ().

Performance Data
The QX100 ddPCR system demonstrates a linear dynamic range, extreme precision, accurate quantitative measurements, and high sensitivity.

Dynamic range. A, concentration results for twofold dilutions from 150 to 150,000 copies per reaction; B, concentration results for 1.1-fold dilutions demonstrate precision at ±10% with a 95% CI. The error bars are at the 95% CI. The reference gene () was constant at 19,000 copies/reaction.

* Replicate variation (95% Cl).
** Alkan C et al. (2009). Nat Gen 41, 1061–1067.