As COVID-19 testing turns into extra broadly obtainable, it is vital that well being care suppliers and public well being officers perceive its limits and the impression false outcomes can have on efforts to curb the pandemic.
A particular article revealed in Mayo Clinic Proceedings calls consideration to the danger posed by overreliance on COVID-19 testing to make medical and public well being choices. The sensitivity of reverse transcriptase-polymerase chain response (RT-PCR) testing and general take a look at efficiency traits haven’t been reported clearly or constantly in medical literature, the article says.
Consequently, well being care officers ought to anticipate a “much less seen second wave of an infection from folks with false-negative take a look at outcomes,” says Priya Sampathkumar, M.D., an infectious illnesses specialist at Mayo Clinic and a examine co-author.
“RT-PCR testing is most helpful when it’s optimistic,” says Dr. Sampathkumar. “It’s much less helpful in ruling out COVID-19. A destructive take a look at usually doesn’t imply the individual doesn’t have the illness, and take a look at outcomes should be thought-about within the context of affected person traits and publicity.”
Even with take a look at sensitivity values as excessive as 90%, the magnitude of threat from false take a look at outcomes shall be substantial because the variety of folks examined grows. “In California, estimates say the speed of COVID-19 an infection could exceed 50% by mid-Could 2020,” she says. “With a inhabitants of 40 million folks, 2 million false-negative outcomes could be anticipated in California with complete testing. Even when only one% of the inhabitants was examined, 20,000 false-negative outcomes could be anticipated.”
The authors additionally cite the consequences on well being care personnel. If the COVID-19 an infection fee among the many greater than four million folks offering direct affected person care within the U.S. have been 10% — far under most predictions ¬¬ — greater than 40,000 false-negative outcomes could be anticipated if each supplier have been examined.
This poses dangers for the well being care system at a vital time. “At present, CDC (Facilities for Illness Management and Prevention) tips for asymptomatic well being care employees with destructive testing might result in their fast return to work in routine medical care, which dangers spreading illness,” says Colin West, M.D., Ph.D., a Mayo Clinic doctor and the examine’s first creator. Victor Montori, M.D., a Mayo Clinic endocrinologist, is also a co-author.
Whereas coping with the enormity of the rising COVID-19 pandemic, it is essential for public well being officers to stay to rules of evidence-based reasoning concerning diagnostic take a look at outcomes and false-negatives. 4 suggestions are outlined within the Mayo Clinic article:
- Continued strict adherence to bodily distancing, hand-washing, floor disinfection and different preventive measures, no matter threat stage, signs or COVID-19 take a look at outcomes. Common masking of each well being care employees and sufferers could also be crucial.
- Improvement of extremely delicate exams or mixtures of exams is required urgently to attenuate the danger of false-negative outcomes. Improved RT-PCR testing and serological assays — blood exams that determine antibodies or proteins current when the physique is responding to infections akin to COVID-19 — are wanted.
- Danger ranges should be rigorously assessed previous to testing, and destructive take a look at outcomes needs to be seen cautiously, particularly for folks in higher-risk teams and in areas the place widespread COVID-19 an infection has been confirmed.
- Danger-stratified protocols to handle destructive COVID-19 take a look at outcomes are wanted, they usually should evolve as extra statistics develop into obtainable.
“For really low-risk people, destructive take a look at outcomes could also be sufficiently reassuring,” says Dr. West. “For higher-risk people, even these with out signs, the danger of false-negative take a look at outcomes requires extra measures to guard in opposition to the unfold of illness, akin to prolonged self-isolation.”
At Mayo Clinic, RT-PCR testing is “considered one of many components we have in mind in deciding whether or not the affected person meets standards for COVID-19,” Dr. Sampathkumar says. If the RT-PCR take a look at is destructive however chest X-ray or CT scan outcomes are irregular, or there was shut contact with an individual who has confirmed COVID-19, the advice is to proceed caring for the affected person as if she or he has COVID-19.
“We have to proceed to refine protocols for asymptomatic sufferers and uncovered well being care employees,” says Dr. Sampathkumar.