Choosing dPCR vs qPCR – Explore the benefits and see if it’s right for your research goals
When comparing dPCR vs qPCR technologies, the key difference is precision power. While both offer highly sensitive and reliable nucleic acid detection and quantification, the key difference between the two technologies can be best described using an analog versus digital radio analogy, says Dr. Jim Huggett, Principal Scientist, National Measurement Laboratory. "With an analog radio, the dial must first be fine-tuned to get the desired station with the least interference. Still, the quality depends on reception and the signal is subject to interference from static. This is qPCR. It is reliable but requires optimization to get a good result, and even then, you must contend with background noise. With digital radio, you simply call up the station and it is either there, with a clear signal, or not. The latter is like dPCR, which provides precise, binary results. It literally counts the presence or absence of DNA molecules. The clarity of results combined with a low error rate makes for an incredibly high level of precision. Digital PCR is well-suited to measure smaller quantitative differences."
Compare and contrast: qPCR vs dPCR
| Real-time PCR/ qPCR | Digital PCR |
|---|---|
| Quantitative, relative or absolute but standard curves or reference samples needed |
Quantitative, absolute and no standards or references needed |
|
Bulk PCR
|
Sample partitioning
|
| Measures PCR amplification at each cycle | Measures at the end of the PCR cycles |
| Detects mutation rate at >1% | Detects mutation rate at ≥ 0.1% (high signal-to-noise ratio) |
| Well-established protocols | Higher precision for higher reproducibility across laboratories |
When to use dPCR vs. qPCR?
When it comes to molecular biology and genomics research involving nucleic acid quantification, scientists often find themselves standing at the crossroads. Which quantification technique to choose to achieve research goals efficiently – the more precise and robust digital PCR (dPCR) or the more standardized and familiar quantitative real-time PCR (qPCR). Both technologies have similarities, but also their benefits and limitations that make the choice application-dependent.
The application grid indicates the suitability level of each technology for some of the common applications.
Droplet digital PCR (ddPCR), one of the earliest forms of digital PCR, could already offer advantages over qPCR for most of the applications above. In ddPCR vs qPCR, qPCR is suitable for applications that require a broad dynamic range, whereas ddPCR is for those applications that require higher precision or analysis of fractional abundance.
The evolution from ddPCR to nanoplate dPCR has widened the scope of this technology to include more applications. The nanoplate dPCR workflow is substantially faster thanks to the simultaneous reading of all sample partitions, front-end automation, and an easy qPCR-like plate set-up. This added speed makes it suitable for screening and high-throughput applications without compromising precision, accuracy and sensitivity.