What Is Cell-Free DNA (cfDNA)? - Seq It Out #19

Learn that cell-free DNA (cfDNA) refers to all non-encapsulated DNA fragments in the bloodstream, including circulating tumor DNA (ctDNA) from cancer cells. These nucleic acid fragments enter the bloodstream during apoptosis or necrosis.

Assess the analytical performance of cfDNA detection methods, demonstrating high sensitivity and specificity for variants at frequencies greater than 0.1% with 20 nanograms of input DNA and greater than 0.5% with 5 nanograms.

Determine the practical detection limits by isolating cfDNA from a 10 milliliter blood sample using the Applied Biosystems MagMax cell-free DNA isolation kit, which routinely yields about 20 nanograms of cfDNA for analysis.

Calculate the expected number of target molecules at different detection thresholds: approximately 25 molecules at 1% limit of detection and only 2-3 molecules at 0.1%, indicating a practical lower limit below which molecules may not be present.

Recognize that cfDNA concentrations are highly variable and can be critically low during early recurrence or development of resistance, which impacts the choice of downstream analytical methods.

Choose between digital PCR for recurrence monitoring studies or next-generation sequencing methods for research and therapy selection based on your specific research objectives and cfDNA characteristics.

Deploy complete liquid biopsy solutions for cfDNA analysis spanning from single target assays to multiple gene assays to support your research needs.