High-fidelity PCR enzymes are used for applications requiring high accuracy during DNA amplification such as cloning, sequencing or mutagenesis. Thermo Scientific Phusion high-fidelity DNA polymerases were created by fusing a dsDNA-binding domain to a Pyrococcus polymerase–like proofreading enzyme. Due to this unique protein fusion engineering, Phusion DNA Polymerases have very low error rates, fast extension rates, and high inhibitor tolerance.

Select a Phusion DNA polymerase best suited for your application

Phusion high-fidelity DNA polymerases are available in a variety of formats. Please reference the table below to find an appropriate Phusion format for your application.

  NEW Phusion Plus DNA Polymerase Phusion High-Fidelity DNA Polymerase Phusion Hot Start II DNA Polymerase Phusion Flash High-Fidelity PCR Master Mix Phusion U Hot Start DNA Polymerase Phusion U Multiplex PCR Master Mix
Fidelity (vs. Taq enzyme) >100x 52x 52x 25x 25x 25x
Tm calculation required No Yes Yes Yes Yes Yes
Enhanced specificity (hot-start version) Yes No Yes Yes Yes Yes
Amplification length Up to 20 kb Up to 20 kb Up to 20 kb Up to 20 kb  Up to 20 kb Up to 2.5 kb
Speed 15–30 sec/kb 15–30 sec/kb 15–30 sec/kb <15 sec/kb 15–30 sec/kb 15–30 sec/kb
GC-rich format Yes (new GC enhanced) Yes Yes No Yes No
dUTP incorporation No No No No Yes Yes
Designed for multiplex PCR No No No No No Yes, up to 20 targets
Stand-alone enzyme format*    
2x master mix format*

* All stand-alone enzymes are supplied with their reaction buffers. The 2x master mix formats include all necessary PCR components except the template and primers.
** Contains green loading dyes and a density reagent for direct gel loading of PCR products


Ordering information for Phusion high-fidelity DNA polymerases

Do you need a DNA polymerase with higher fidelity and/or performance than Phusion enzymes? Discover Invitrogen Platinum SuperFi II DNA Polymerase with >300x Taq fidelity and a simplified PCR protocol.