As Joe Biden was inaugurated, the WHO released guidelines making it harder to diagnose positive cases.
- One PCR test isn't enough anymore. Health care providers "must" now consider other factors before diagnosing.
- A second PCR test is now needed to diagnose asymptomatic cases. Previously, one was enough.
- For retesting, the WHO now warns about PCR cycle counts. High cycle counts inflated case numbers with false positives.
- The Result? The Biden Administration will log fewer positive cases, all because of new testing guidelines.
The PCR Test Changes
A single positive PCR result is no longer a positive case.
A second PCR test is also now needed if the individual doesn't have any symptoms.
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. - WHO
The Tests Were Being Used Improperly
In August, NYT reported in over-sensitive tests resulted in false positives, inaccurately portraying the extent of the pandemic.
Up to 90% of people that tested positive were barely carrying any virus.
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.
Sources: New York Times, WHO, medRxiv