For mutation detection in FFPE tumor samples, how should one choose between NGS panel and ddPCR?

If you are only testing known hotspots in KRAS, NRAS, and BRAF, ddPCR is indeed more robust than Sanger for low-abundance mutations, especially for the small amount of mutant template derived from FFPE samples. ddPCR can separate and quantify wild-type and mutant through digital partitioning, making it less likely to be overwhelmed by background. However, its site scalability is poor: each additional hotspot requires an extra reaction, so you should consider whether you want to expand to other genes later. A small NGS panel can cover multiple exons or even more genes in one run and can detect rare or compound mutations, but FFPE samples first need quality control for the degree of degradation, and library complexity and background noise also need to be assessed. It is recommended to first use several known low-abundance specimens and serially diluted standards to determine the limit of detection and reproducibility separately, and then see which is more suitable for your reporting needs.

For kit lead times, it is advisable to have distributors quote both in-stock and future delivery timelines. Imported ddPCR or NGS panels often require 2–6 weeks, while domestic kits generally take 1–4 weeks, but popular catalog numbers may face customs or cold-chain delays. Before implementation, first review your existing platform: if you have a digital PCR instrument, prioritize compatible reagents; if you have an NGS sequencer, then check whether the panel is compatible. During validation, do not rely only on positive standards; select several samples with Sanger-confirmed mutations and several low-abundance missed-detection specimens, run both ddPCR and NGS, and compare detection rates, Ct values/read depth, and turnaround time. When changing kit lots, also perform external quality assessment or third-party quality control materials to confirm lot-to-lot consistency.

At a scale of 20 cases per week, my experience with ddPCR and small NGS panels is as follows: ddPCR is fast to operate, with a single run taking only a few hours, but once sample numbers increase, loading, sealing, and data interpretation become very labor-intensive, especially when three genes and multiple hotspots are involved, as the number of reactions can easily double; the per-sample cost rises linearly with the number of reactions. Small NGS panels require longer preprocessing, library preparation, and instrument run time, but when 20 cases are batched together, the per-sample cost is diluted, and labor is mainly in library construction and data analysis, requiring someone who can review QC and filter low-quality variants. If your turnaround time for reports is not tight, NGS is more suitable for routine batch testing; if the clinic urgently needs results for a few hotspots the same day, ddPCR is more flexible.