WHO releases new tightened guidelines regarding the diagnostic criteria for COVID-19. PCR positive no longer means you have COVID-19. You need a second test to confirm you have the virus
Yesterday, The World Health Organization released a new set of tightened guidelines and diagnostic criteria for detecting COVID-19 on the same day the 46th President of the United States was sworn in. The new guidelines may impact how healthcare professionals count the number of people infected with COVID-19.
The new tightened guidelines, which were released on January 20, were actually dated January 13. Call it coincidence or a chance, The WHO gave no reasons as to why the guidelines were delayed for one week before it was released.
The new guidelines involve the use of Nucleic acid testing (NAT) technologies that use polymerase chain reaction (PCR) for the detection of SARS-CoV-2. The WHO said the new guidelines “clarify information previously provided” by the organization.
Now according to the new WHO guidelines, a single positive PCR test for the virus isn’t going to cut it anymore. The fact that you are PCR positive no longer means you have COVID-19. In other words, you don’t have COVID-19 unless you get a second test to confirm it, and are presenting clinical symptoms. WHO also said that, even if you don’t show any symptoms, you’ll need to get a second test for confirmation as well.
In addition, The new WHO guidelines now demand that clinicians “must” also consider a wide array of other factors, like “timing of sampling, specimen type, assay specifics, clinical observations, patient history, confirmed status of any contacts,” and even something called “epidemiological information”—whatever that exactly is—before diagnosing anyone with COVID-19.
However, these tightened guidelines should not a surprise for anyone who has been following the organization. WHO is just returning back to what used to be the standard operating procedure. Before coronavirus hit in December 2020, neither WHO nor the CDC had ever considered a single positive PCR test sufficient for diagnosing viral infection.
Back in August, we wrote about how 90% of people who tested positive in 3 states barely carried coronavirus. Stunning new research also found that the usual COVID-19 PCR diagnostic tests may simply be too sensitive and too slow to contain the spread of the virus.
For example, in all four epidemics prior to COVID-19 since 2000, The CDC and WHO were concerned about the high false-positive rates for PCR tests and issued guidelines to try and minimize them. But for COVID-19, the two organizations somehow forgot all about PCR false-positive rates.
In research published at medRXiv, titled, “Diagnosing COVID-19 infection: the danger of over-reliance on positive test results,” the authors provided evidence that shows false-positive PCR results are common enough to impact clinical and policy decisions.
20 January 2021
Geneva
Reading time: 1 min (370 words)
Product type: Nucleic acid testing (NAT) technologies that use polymerase chain reaction (PCR) for detection of SARS-CoV-2
Date: 13 January 2021
WHO-identifier: 2020/5, version 2
Target audience: laboratory professionals and users of IVDs.
Purpose of this notice: clarify information previously provided by WHO. This notice supersedes WHO Information Notice for In Vitro Diagnostic Medical Device (IVD) Users 2020/05 version 1, issued 14 December 2020.
Description of the problem: WHO requests users to follow the instructions for use (IFU) when interpreting results for specimens tested using PCR methodology.
Users of IVDs must read and follow the IFU carefully to determine if manual adjustment of the PCR positivity threshold is recommended by the manufacturer.
WHO guidance Diagnostic testing for SARS-CoV-2 states that careful interpretation of weak positive results is needed (1). The cycle threshold (Ct) needed to detect virus is inversely proportional to the patient’s viral load. Where test results do not correspond with the clinical presentation, a new specimen should be taken and retested using the same or different NAT technology.
WHO reminds IVD users that disease prevalence alters the predictive value of test results; as disease prevalence decreases, the risk of false positive increases (2). This means that the probability that a person who has a positive result (SARS-CoV-2 detected) is truly infected with SARS-CoV-2 decreases as prevalence decreases, irrespective of the claimed specificity.
Most PCR assays are indicated as an aid for diagnosis, therefore, health care providers must consider any result in combination with timing of sampling, specimen type, assay specifics, clinical observations, patient history, confirmed status of any contacts, and epidemiological information.
Actions to be taken by IVD users:
Contact person for further information:
Anita SANDS, Regulation and Prequalification, World Health Organization, e-mail: rapidalert@who.int
References:
1. Diagnostic testing for SARS-CoV-2. Geneva: World Health Organization; 2020, WHO reference number WHO/2019-nCoV/laboratory/2020.6.
2. Altman DG, Bland JM. Diagnostic tests 2: Predictive values. BMJ. 1994 Jul 9;309(6947):102. doi: 10.1136/bmj.309.6947.102.
TRIAL International has filed legal complaints in Switzerland, urging an investigation into the Swiss-incorporated Gaza…
The Ministry of Foreign Affairs summoned the U.S. Chargé d'Affaires on Friday, June 30 to…
(by H.E. Tong Defa, Ambassador of China to Ghana) There is a famous saying about…
Amina Bouayach President of CNDH Thu, 05/29/2025 - New York (UN) 29 May 2025 (SPS)-…
Former Special Prosecutor Martin Amidu has taken a strong swipe at former Attorney-General Godfred Yeboah…
Nana Kwasi Gyan-Apenteng, distinguished journalist, passed away in London yesterday after a short illness with…
View Comments
Hey! I know this is somewhat off topic but I was
wondering which blog platform are you using for this site?
I'm getting sick and tired of Wordpress because I've had issues with hackers and I'm looking at alternatives for another platform.
I would be awesome if you could point me in the direction of a good platform.
I enjoy looking through a post that will make people think.
Also, many thanks for permitting me to comment!
Superb, what a weblog it is! This blog provides useful data to us, keep it
up.
continuously i used to read smaller content that as well clear their motive,
and that is also happening with this paragraph which I am reading here.
Asking questions are actually nice thing if
you are not understanding anything fully, but this paragraph offers pleasant understanding yet.
Yes! Finally someone writes about Small Business Advice.
After looking at a handful of the articles on your site, I honestly like your way of writing a blog.
I saved as a favorite it to my bookmark site list and will be checking
back soon. Please check out my website as well and tell me how
you feel.
I blog quite often and I truly thank you for your content. Your article has really peaked my interest. I am going to book mark your site and keep checking for new information about once per week. I opted in for your Feed as well.
Having read this I believed it was really enlightening. I appreciate you finding the time and effort to put this informative article together. I once again find myself personally spending way too much time both reading and leaving comments. But so what, it was still worthwhile!
Hello, Neat post. There's an issue with your site in internet explorer, might check this?
IE still is the marketplace leader and a big portion of folks will leave out your
fantastic writing because of this problem.