Droplet digital PCR improved the EGFR mutation diagnosis with pleural fluid samples in non-small-cell lung cancer patients.

•The clinical value of ddPCR in pleural fluid was first demonstrated in this study.•With ddPCR, the EGFR mutation detection rate in pleural fluid was significantly elevated.•Compared with ARMS, EGFR-positive patients detected by ddPCR had higher ORR.•Compared with sequencing, EGFR-positive patients detected by ddPCR had longer PFS.•The obtained experience is practical and favorable for the proper application of ddPCR.