Negative Corona Tests offer no security
The common Tests for the detection of acute infection with the new Coronavirus SARS-CoV-2 can mediate in case of a negative test result is a false sense of security and thus, indirectly, have a significant impact on the containment of the pandemic have, warn Researchers from the Mayo Clinic (USA). For example, the health authorities have to reckon with a “less visible second wave of Infection of persons with false-negative test results,” warns the expert Dr Priya Sampath Kumar of the Mayo Clinic.
Over-reliance on COVID-19 Tests in making decisions in clinical and public health carries with it, according to the researchers some of the risks. Especially the so-called RT-PCR can run Tests (Reverse transcriptase-Polymerase chain reaction) to a false sense of security, which can affect the balance of measures and the evaluation of the infection events is negative, report the researchers in the journal “Mayo Clinic Proceedings”.
Positive Tests are most useful?
The sensitivity of the RT-PCR (Reverse transcriptase-Polymerase chain reaction), and the General performance characteristics of the Tests are not described in the medical literature is clear and consistent, so the criticism in the article. Therefore, the “RT-PCR are most Tests are most useful when they are positive,” says Dr. Sampath Kumar. However, they are less useful to COVID-exclude 19. A negative Test does not mean often that the Person suffers from the disease.
Test with a remaining uncertainty
Because even in a test sensitivity of up to 90 percent of the extent of the risk was incorrect test results considerably and with an increasing number of people tested will increase the number of false test results.
The example of California, the expert calculates that, for an assumed infection rate of 50 percent of the population at 40 million people, 20 million would be infected. If ten percent of them, the Test falsely negative result, were Infected two million undiagnosed. Even at 99-percent test accuracy 20.000 remained false-negative results.
Impending impact of the health personnel
In the article, the possible impact on the health personnel in the United States. “If the COVID-19-infection rate among the more than four million people in the USA direct patient care, would say amount to ten percent – far below most of the before – and- would more than 40.000 wrong to expect negative results, if all were to be tested”, warn the researchers.
Danger of the proliferation
This represents a risk for the health care system in this critical time, because in the United States, “the guidelines of the CDC (Centers for Disease Control and Prevention) for asymptomatic health care Workers with negative test results cause you to return immediately in the clinical routine care, increasing the risk of spread of diseases,” said study first author Dr. Colin West.
“For people with truly low-risk negative test results may be sufficiently reassuring,” says Dr. West. However, in individuals with a higher risk, even in people without symptoms, requires “the risk of false-negative test results, additional measures to protect against the spread of the disease, such as, for example, an advanced self-isolation.”
Several criteria should be observed
At the Mayo Clink of the RT-PCR Test is only “one of many factors that we take into account in deciding whether the Patient meets the criteria for COVID-19,” says Dr. Sampath Kumar. If the Test is negative, but the results of the x – ray or CT scan of the chest are abnormal or there was close contact with a sick Person, loud “, the recommendation to provide the patient, if he had COVID-19.”
Minimize the risk of incorrect test results
In order to avoid risks due to false-negative test results that are cited in the contribution of the Mayo Clinic four principle points:
- Furthermore, strict adherence to physical distancing, hand washing, surface disinfection and other preventive measures, regardless of risk level, symptoms, or COVID-19-test results.
- The development of highly sensitive Tests or test combinations in order to minimize the risk of false-negative results. Improved RT-PCR Tests and antibody Tests are required.
- The disease risk must be estimated prior to the Test carefully, and negative test results should be evaluated with caution, especially in the case of people from groups at risk and from areas where widespread COVID-19 infections have been confirmed.
- It is risk-stratified protocols for dealing with negative COVID-19-test results are required (detection of the risk of Disease despite the negative Test), the need to continue to develop, as soon as more statistics are available.
In addition, the recommendations for dealing with asymptomatic patients, as well as for exposed personnel in the health sector need to be further refined, says Dr. Sampath Kumar. (fp)