An ultrafast microfluidic PCR module (30 PCR cycles in 6 min) based on the oscillating fluid plug concept was developed. A robust amplification of native genomic DNA from whole blood samples could be achieved at operational conditions established from systematic investigations of key parameters including heat transfer and in particular flow velocities. Experimental data were augmented with results from computational fluid dynamics simulations. The reproducibility of the current system was substantially improved compared to previous concepts by integration of a closed reservoir instead of utilizing a vented channel end at ambient pressure rendering the devised module suitable for integration into complex sample-to-answer analysis platforms such as point-of-care applications.