Rare target quantification in liquid biopsy


Liquid biopsies are used to identify and track genetic mutations that cause cancer, enabling researchers to detect cancer early, measure therapeutic response, quantify residual tumor burden, and monitor emerging resistance to potential therapies. Liquid biopsies utilize cell-free DNA (cfDNA) that is derived from cells, both normal and cancerous, that have undergone apoptosis or necrosis and released their DNA contents into their environment (1). The component of cfDNA that is released from cancer cells is more commonly referred to as circulating tumor DNA, or ctDNA.

Detecting ctDNA for liquid biopsy applications is challenging because the molecules bearing the cancer mutations are only a small fraction of the total circulating  cfDNA collected in the sample. Digital PCR (dPCR) is an established method for the fast and reliable identification of genetic mutations. Accurate quantification of single nucleotide polymorphisms that occur in low abundance amongst wild type background DNA requires an appropriate liquid biopsy assay with outstanding sensitivity and specificty. Applied Biosystems Absolute Q Liquid Biopsy dPCR assays are a precise, cost-effective, and rapid method for monitoring response and resistance to treatment by testing for relevant cancer-driver and therapy-resistant mutations.

Absolute Q Liquid Biopsy dPCR assays

Absolute Q Liquid Biopsy dPCR assays enable reproducible, specific detection of known somatic mutations. Each predesigned assay has been validated using controls to detect down to 0.1% variant allele frequency in genes relevant for cancer research.

Absolute Q Liquid Biopsy dPCR assays are:

  • Simple—preformulated and verified assay in a single tube, enabling you to immediately start your research
  • Fast—minimal hands-on time; results in 90 minutes when used with the QuantStudio Absolute Q Digital PCR System
  • Highly Sensitive—detect down to 0.1% variant allele frequency
  • Robust—analyze your data with confidence using verified assays backed by a performance guarantee*

We stand behind every predesigned Absolute Q dPCR Assay that you buy from us

We guarantee the performance of all of our predesigned Absolute Q assays for dPCR experiments. Our application‑specific portfolio of assays enables you to obtain the highest quality and performance available. These assays are designed and verified using up-to-date annotations and gold-standard Applied Biosystems TaqMan chemistry.

If an Absolute Q Digital PCR Assay does not perform according to conformance documentation, we will replace it at no cost or credit your account.*

Learn more about the Absolute Q dPCR Assay guarantee ›


Figure 1. Quantification of cancer mutations using Absolute Q Liquid Biopsy Digital PCR assays on as QuantStudio Absolute Q Digital PCR System.

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Custom designed assays

Can’t find the assay you need? Contact us and our experts can help design a digital PCR assay formulated for success based on your target sequence of interest. Or submit the primer/probe sequences of your own design.

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Robust digital PCR master mix solutions


For DNA/cDNA targets

Absolute Q DNA Digital PCR Master Mix (5X) is optimized for use with the QuantStudio Absolute Q Digital PCR System. The mix is designed as a single‑tube, one‑step formulation for fast, simple, and reproducible RNA quantification, requiring minimal upstream processing steps.

Key product features:

  • Fast time-to-result — about five minutes of hands‑on time and results in less than two hours
  • Convenient 1step formulation — save time and effort by eliminating upstream cDNA conversion steps
  • High sensitivity — detect <1 copy/μL of a specific target within a 4‑plex reaction
  • Optimized for multiplexing — detect up to four targets in a single reaction
  • High precision — distinguish 20% differences in RNA concentration

For RNA targets

Absolute Q RNA 1-step Digital PCR Master Mix (4X) is optimized for use with the QuantStudio Absolute Q Digital PCR System and Absolute Q digital PCR assays in a simple one-step workflow that does not require upfront cDNA conversion.

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Absolute Q liquid biopsy assays


  1. Chu D, Park BH (2017) Liquid biopsy: unlocking the potentials of cell-free DNA. Virchows Arch 471(2):147–154.

 *Terms and conditions apply. For complete details of the guarantee, go to thermofisher.com/absoluteqassayguarantee

For Research Use Only. Not for use in diagnostic procedures.

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