The COVID-19 pandemic made ‘PCR testing’ a household phrase. But what quality and service features are important for accurate, convenient PCR testing that can be used across a broad range of applications? Medix Biochemica is offering a novel DNA polymerase in order to develop PlexTaq® 5x qPCR Multiplex Master Mix for use in PCR testing.1 Here we share some of the background, unique features and key takeaways of PlexTaq®, all of which play a role in convenient, reliable, sensitive and useful PCR testing.1-4

Why use the Medix Biochemica PlexTaq® for IVD pathology testing?

PlexTaq® 5x qPCR Multiplex Master Mix offers robust PCR (polymerase chain reaction) performance for a wide range of applications.1-4 It contains all the components needed for rapid, sensitive and reproducible quantification of DNA and cDNA.1-4 Medix Biochemica’s unique engineered Taq DNA polymerase variant, which is used in PlexTaq® products, is very stable at room temperature,  offers a fast start feature and exhibits high specificity and sensitivity in a PCR setup.1

Find out more about what Medix Biochemica can do for you, and be sure to get in touch with us should you have any questions or concerns.

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3 Key PlexTaq® takeaways

1. Available as a freeze-dryable (or Lyo-Ready) formulation

In keeping with the future of molecular diagnostic testing, PlexTaq® is available in a formulation that can be freeze-dried (lyo-ready). Lyophilized PlexTaq performs as effectively as the liquid form whilst offering the intrinsic advantages of an engineered, room-temperature-stable Taq DNA polymerase as well as reduced time for assay preparation (just add primers/probes). Quantifiable gains from using a lyophilized PlexTaq® in molecular biology assays include room-temperature shipping and storage, extended shelf life, flexible assay designs and increased flexibility in sample volume.

2. A novel engineered DNA polymerase: Medix Biochemica has the expertise
At Medix Biochemica, we shape enzymes to behave the way biotechnology needs them to.3 During PCR testing, DNA polymerases can impact the efficacy of the test in various ways, including:1

- Undesired DNA synthesis due to either mispriming or the formation of primer dimers. These 2 events, which occur within seconds at ambient temperature, can hinder the sensitivity and specificity of a PCR test. 
- Being susceptible to potential inhibitors from clinical specimens. This means that nucleic acids from the specimen have to be purified prior to amplification.


At Medix Biochemica, we have the experts at hand and they’ve addressed these challenges by engineering a unique DNA polymerase used in PlexTaq®. Produced in-house to ISO13485 standards,1-3 this novel polymerase offers:

  • Inactivity at room temperature1

To create a hot start DNA polymerase that exhibits higher specificity and sensitivity in a PCR setup, we generated a mutant that only activates at the optimal PCR cycling temperatures: 

Figure 1: The mutation in the α helix 28 of Taq Hotstart DNA Polymerase confers inactivity of the enzyme at room temperature.

  • Improved hot start activity1

Additionally, we designed an aptamer sequence to bind to the enzymatic pocket of the active site and block the activity of the enzyme in a thermally reversible manner.

Figure 2: Enzyme inactivation at lower temperatures is achieved by a tight bond of the aptamer to the polymerase. Temperatures above 55° C results in an activation of the enzyme by dislodging the aptamer from the active site.

  • Reduced time to results1

The PCR run time can be significantly reduced, since no activation step is needed. Fast start PCR protocol can be used for multiplex pathogen detection.

  • Robustness and uniform amplification in multiplexing1

The Taq DNA polymerase offers high sensitivity and specificity for multiplexing. It has been successfully used in amplification of up to 30 different DNA sequences in one reaction.

  • The ability to directly test from crude samples (any blood and plasma), saving critical time and reducing high costs2,3

Targets can be reliably amplified from a variety of sources without a purification step, because the polymerase exhibits a strong tolerance to common PCR inhibitors. This means that the extraction step can be skipped and the blood sample simply added into the real-time PCR test– saving significant time and cost.

To access a scientific poster presented at European Congress of Clinical Microbiology & Infectious Diseases (ECCMID) 2023 about this novel engineered DNA polymerase, please click below:

Download ECCMID 2023 Scientific Poster


3. Medix Biochemica offers unique, tailored customization, working with our customers to bring you what you need2,3

We offer support beyond simply providing a novel product. As a quality-driven organization, we offer a high degree of flexibility and customization. We can customize, bulk fill, aliquot or freeze-dry for our customers. 

What’s more, we can provide lyo-ready PlexTaq® or we can show you how to effectively and precisely freeze-dry it yourself – the right way. We can also freeze-dry customized products for you if that’s what your team needs.

We’re excited that, in keeping with Medix Biochemica’s drive to provide quality products and service excellence to the industry, PlexTaq® 5x qPCR Multiplex Master Mix enhances convenience, accuracy, robustness, speed and simplicity during PCR testing across a broad range of applications. It’s a step into the cutting-edge future of sensitive and reliable detection of pathogens.1-4

For more information on this novel engineered DNA polymerase, please click below:

Download our PlexTaq 5x qPCR Multiplex Master Mix leaflet



  1. Medix Biochemica. Data on file. 33rd ECCMID poster: Clinical utility of a novel engineered DNA polymerase for the sensitive and reliable detection of pathogens. 2023.

  2. Expert opinion. Interview follow-up with Ramon Kranaster, R&D Director , Medix Biochemica. May 05, 2023.

  3. Expert opinion. Interview with Ramon Kranaster, R&D Director,  Medix Biochemica. May 05, 2023.

  4. Medix Biochemica. Data on file. PlexTaq® 5x qPCR Multiplex Master Mix is now lyo ready (#4000). 2023.

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