HiDi^® (pronounced “Heidi”) stands for highly discriminating.¹ A highly discriminating  enzyme is an enzyme that’s been artificially modified to work in highly selective PCR testing and mutation detection.¹ They are the gold standard for cases where a researcher or healthcare provider is tasked with ‘finding a needle in a haystack’, delivering a level of certainty that other products can’t provide.¹ 

What Are HiDi® Enzymes and What Sets Them Apart?

A HiDi^® enzyme differentiates between primers that bind to their intended targets versus primers that are not fully binding.¹ In simple terms, the enzyme discards any mismatched primers and only ‘searches’ for the primers that are fully matched to the enzyme’s target sequences.¹ 

Many enzymes on the market today feature low discrimination or none at all.¹ This becomes an issue when tests need to focus on specific primers, e.g. in as-PCR testing.¹ 

Highly discriminating enzymes, on the other hand, are exceptionally useful in these cases.¹

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3 Applications for HiDi^® enzymes:

HiDi^® enzymes can be used in genotyping to determine the alleles (genetic variants) an individual might have inherited.^1-3

HiDi^® gives testers key advantages in genotyping:²

• Up to 30% total time and labor cost reduction compared to PCR- and NGS-based genotyping
• No significant protocol changes required
• Enables confident acceleration of research
  
  

HiDi^® products can be used in as-PCR testing to detect cancer mutations.^1,2 

The traditional PCR workflow would include primer design, followed by PCR testing, followed by separation of DNA fragments (gel electrophoresis).^2,4 With HiDi^®, the workflow is shorter, starting with primer design and progressing straight to quantitative (real-time) PCR.² qPCR can simultaneously amplify and detect the target DNA.⁵

3. CRISPR-Cas SNP quality control
SNPs can provide crucial information about an individual’s genetic makeup and indicate their predisposition towards certain diseases.² SNPs introduced by CRISPR technology must undergo quality control filtering which can be done by HiDi very efficiently.¹

The traditional CRISPR workflow for SNP quality control takes up to 60 days, but the workflow using HiDi^® DNA polymerase only takes just over 40 days.²

This means:² 

• 20% less time required
• 20% labor cost reduction
• 60% overall total workflow cost reduction
• 50% less plastic consumable waste used
• 65% lower cost associated with external services
  
  

HiDi^® Applications in HLA Typing and Matching and in Liquid Biopsies

HiDi^® enzymes are valuable in HLA typing and matching, helping to test patients and donors for bone marrow and cord blood transplant compatibility.^1,6

HiDi^® enzymes can also be used in liquid biopsies to detect mutations in a high background of wild-type or ‘irrelevant’ biotype sequences.^1,2 This is useful for tracking the progress of a disease and testing the efficacy of treatment, e.g. the effect of chemotherapy on cancer progression.¹

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HiDi^® Enzymes From Medix Biochemica

There are 4 proprietary HiDi^® formulations in Medix Biochemica’s HiDi^® product family. These include enzymes, Taq enzymes and ready-to-use master mixes:²

• HiDi^® DNA polymerase
• HiDi^® Taq DNA polymerase
• HiDi^® 2x PCR Master Mix
• HiDi^® Taq 2x PCR Master Mix
  
  

What can you expect from Medix Biochemica’s HiDi^® products?²

• Excellent SNP discrimination: Differentiate alleles reliably.
• Superior performance: Excellent for as-PCR and the first choice for highly selective PCRs. Outperform competitors.
• Easy primer design: Standard primers, changing only the 3’ nucleotide.
• Highly sensitive: Fewer than 10 copies of a mutation can be detected in a background of >10 000 wild-type copies.
• No false amplification: Aptamer-based hot-start prevents false amplification and provides a fast-start function.
  
  

Benchmarking data for HiDi^® Taq DNA polymerase

Benchmarking data clearly shows the benefits of Medix Biochemica’s HiDi^® Taq DNA polymerase.⁷ 

This highly selective DNA polymerase variant is specially evolved for all assays where high single nucleotide discrimination is required, e.g. as-PCR, mutation detection and genotyping.⁷

HiDi^® Taq DNA polymerase efficiently discriminates matched primers from those that have a mismatch at the 3'-terminus.⁷ It outperforms competitor products in both signal generation and discrimination.⁷

HiDi^® enzymes are the gold standard for high discrimination as-PCR testing, liquid biopsy and HLA typing and genotyping.² Medix Biochemica is proud to offer HiDi^® products of superior quality.

References:

1. Expert opinion. Interview with Ramon Kranaster, Managing Director and R&D Director at myPOLS Biotec GmbH. May 16, 2023.  
2. Data on file. Medix Biochemica. HiDi^® Family: True gold-standard for high discrimination allele-specific PCR. February 14, 2023.
3. Karch SB. Autopsy: molecular. In: Payne-James J, Byard RW, eds. Encyclopedia of Forensic and Legal Medicine (Second Edition). Elsevier; 2016:290-296. doi:10.1016/B978-0-12-800034-2.00041-0.
4. Polymerase chain reaction (PCR). Khan Academy. Accessed June 13, 2023. https://www.khanacademy.org/science/ap-biology/gene-expression-and-regulation/biotechnology/a/polymerase-chain-reaction-pcr.
5. Hussain B, Yüce M, Ullah N, et al. 3 - Bioconjugated nanomaterials for monitoring food contamination. In: Grumezescu AM, ed. Nanobiosensors. Academic Press; 2017:93-127. doi:10.1016/B978-0-12-804301-1.00003-5.
6. HLA basics. BeTheMatch.org. Published March 10, 2023. Accessed June 13, 2023. https://bethematch.org/transplant-basics/how-blood-stem-cell-transplants-work/hla-basics/.
7. Data on file. Medix Biochemica. Benchmarking data for HiDi^® Taq DNA polymerase (#9201).
8. Data on file. Medix Biochemica 33rd ECCMID. 2023.