PCR and Dispelling the Falsehoods
PCR, that one subject which has always been commonly misconstrued, misinterpreted and lies have spread. You’ll hear from people all over the internet from fictitious articles claiming all sorts, to individuals (that have no clue about PCR) ringing up hospitals telling them about lawsuits because they’re using the cycle threshold at 45. Below are the facts.
➡️ PCR and telling the difference between two viruses.
PCR is sequence-specific, so what this means is that each test is designed to identify very specific sequences of nucleic acids. (Source: CDC, Division of Laboratory Systems, July 21, 2021)
➡️ PCR testing and false positives
False positives are very rare unless the sample has been contaminated, false negatives are more likely than false positives as PCR tests are very accurate. False negatives are more common, they can occur between 2% and 37%. (Source: https://www.bmj.com/content/369/bmj.m1808)
➡️ Kary Mullis
The main misinterpretation is surrounding the creator and his interview which has been seen multiple times on YouTube, they were discussing HIV and AIDS. So he never stated anything about the reliability of PCR tests. (Source: http://www.virusmyth.org/aids/hiv/jlprotease.htm)
➡️ CDC removal of a EUA License for one PCR test
So earlier this year the CDC issued a warning regarding the Curative SARS-CoV-2 Assay, co-developed by Korvalabs and San Dimas, CDC stated its removal for EUA was based on risks on false negatives which the company disputes but at the request of the company they wanted the EUA revoked as they’re transitioning away from this at their labs. Now the CDC wants to use Multiplex PCR testing which can detect both Flu and SARS-CoV-2 (Source: https://www.genomeweb.com/molecular-diagnostics/cdc-withdraw-eua-covid-19-test-fda-revokes-three-other-euas-non-use-agency#.YQACaEBOmHs)
➡️ Multiplex PCR
Multiplex PCR (polymerase chain reaction) can be used to diagnose multiple viruses simultaneously from a single swab. (Source: http://www.premierbiosoft.com/tech_notes/multiplex-pcr.html)
➡️ The Steps of PCR
A sample is collected, if RNA is collected this would need to be converted back to DNA. Using the enzyme known as reverse transcriptase Primers would then be used, with blocks and enzymes are added for amplification. Then the PCR test can accurately detect the specific gene(s) that matches the primers, this is why the testing is so accurate, anything else in there will not be picked up. If the specific gene(s) are not in the primers then the test would come back negative for SARS-CoV-2 or Influenza. (Source: https://discoverysedge.mayo.edu/2020/03/27/the-science-behind-the-test-for-the-covid-19-virus/)
➡️ PCR Primers
The definition: PCR primer design is the creation of short nucleotide sequences for use in amplifying a specific region of DNA. (Source: https://www.genome.gov/genetics-glossary/Primer)
PCR primers are designed to: Highly conserved DNA regions, Protein-coding regions with low degeneracy, More conserved regions that flank variable regions.
PCR primers are not designed to: Repeat regions, Regions with secondary structure, Regions that can form primer-dimers, Regions with low G/C content. A primer is a short single-stranded nucleic acid used by all living organisms in the initiation of DNA synthesis. (Source: Cox, Michael M. (2015). Molecular Biology: Principles and Practice. 41 Madison Avenue, New York, NY 10010: W. H. Freeman and Company. pp. 221–238, 369–376, 592–593. ISBN 9781464126147)
Guideline on primers: “Here are some guidelines for designing your PCR primers: Aim for the GC content to be between 40 and 60% with the 3' of a primer ending in G or C to promote binding. A good length for PCR primers is generally around 18–30 bases. Specificity usually is dependent on the length and annealing temperature.” Source attached also explains more in-depth about Primer design too. (Source: https://www.thermofisher.com/blog/behindthebench/pcr-primer-design-tips/#:~:text=Here%20are%20some%20guidelines%20for,or%20C%20to%20promote%20binding.&text=A%20good%20length%20for%20PCR,on%20length%20and%20annealing%20temperature)
➡️ Cycle Threshold
This cycle repeats until the Ct (cycle threshold) is reached. If something is detected, we then look at how many cycles it took to detect it. If it takes fewer cycles, it means that more of the specific genetic material was present in the sample. If nothing is detected, that means the gene was not present in the sample. (Source: https://assets.publishing.service.gov.uk/government/uploads/system/uploads/attachment_data/file/926410/Understanding_Cycle_Threshold__Ct__in_SARS-CoV-2_RT-PCR_.pdf)
➡️ Cycles
The fallacy that if a cycle threshold of 35 or above has been used the test supposedly is invalid is completely untrue as seen from the rest of the evidence on this post, the test is highly accurate and this false claim seems to have stemmed from an Instagram post. No source as that post has since been removed.
➡️ RNA Viruses
SARS-CoV-2 and Influenza A/B are all RNA viruses, RT-PCR (Reverse Transcription Polymerase Chain Reaction) is used. Before amplification, the RNA of the virus is converted DNA strand by a reverse transcriptase enzyme in order for PCR reactions to proceed. What is an RNA virus? An RNA virus is a virus that has (ribonucleic acid) RNA as its genetic material. (Source: https://archive.org/details/basicvirology0000wagn)
Notable human diseases caused by RNA viruses include the common cold, influenza, SARS, MERS, COVID-19 (SARS-CoV-2), Dengue Virus, hepatitis C, hepatitis E, West Nile fever, Ebola virus disease, rabies, polio, mumps, and measles. Introduction to RNA Viruses: “RNA viruses replicate their genomes using virally encoded RNA-dependent RNA polymerase (RdRp). The RNA genome is the template for the synthesis of additional RNA strands. During replication of RNA viruses, there are at least three types of RNA that must be synthesized: the genome, a copy of the genome (copy genome), and mRNAs. Some RNA viruses also synthesize copies of subgenomic mRNAs. RdRp is the key player for all of these processes. RdRps of all RNA viruses probably arose from a common ancestor.” (Source: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7173417/)
➡️ Conclusion
As we can see from the above, PCR as a methodology of testing is very accurate. All strawman claims have been refuted with evidence-based information including the very commonly spread false claim about Kary Mullis, this claim is literally everywhere.
💥 Thanks for reading, Lawrence. Please consider a small contribution, in the form of a beer as all articles are created in my small amount of spare time: https://www.buymeacoffee.com/LawrenceRob