Other tests vs AVCT’s, the best and only so far???4 May 2020 09:25
The article below reviews studies made into antibodies based tests. The main concerns raised are “sensitivity and specificity”, as well as “lateral flow immunoassays” test vs lab test. All these concern are overcome with avct affirmers antigen based test and it’s 2 US manufacturers partners.
“How (Not) to Do an Antibody Survey for SARS-CoV-2”
Catherine Offord
Apr 28, 2020
“Both the Santa Clara and the LA County studies used a test kit manufactured by Chinese company Hangzhou Biotest Biotech, which is not on China’s approved manufacturers list and has since been banned from exporting its kits, NBC reports. The US Food and Drug Administration (FDA) allows this kind of kit to be marketed in the US, but has not formally approved it or vouched for its efficacy.
The test is based on what’s known as a lateral flow immunoassay and is designed to detect antibodies in blood taken from a finger prick. Unlike lab-based tests on larger blood samples, which allow for repeat testing and provide quantitative results of antibody abundance, these so-called “point-of-care” kits return a one-off “positive” or “negative” based on some threshold antibody level set by the manufacturer.
For some researchers in public health, this is a non-starter. “I don’t think any of the current point-of-care tests are appropriate for use in seroprevalence surveys,” says Michael Busch, the director of Vitalant Research Institute, a nonprofit transfusion medicine organization. His team is coordinating a long-term, NIH-funded seroprevalence study using lab-based tests of donor blood across the US—initially in six metropolitan areas, but later in additional parts of the country.
Good antibody surveys require samples that can be retested, he adds. While lateral flow immunoassays offer rapid results, they’re “very non-specific [and] are not amenable to repeat testing and confirmation. . . . If you don’t have a good test, there’s no point in running a serologic survey.”
Neeraj Sood, the vice dean for research at the University of Southern California’s Price School of Public Policy and a collaborator on both the Santa Clara and LA County studies, argues that you “don’t need a perfect test,” provided you understand the test’s performance—in particular, its sensitivity and specificity.
A very sensitive test returns no or few false negatives for people who have the antibodies. A very specific test returns no or few false positives for people who don’t. When trying to detect something relatively rare such as SARS-CoV-2, specificity is usually the primary consideration because it’s important to avoid the detection of other things in the blood—such as antibodies for any of the relatively harmless coronaviruses already common in humans.”
https://www.the-scientist.com/news-opinion/how-not-to-do-an-antibody-survey-for-sars-cov-2-67488?utm_content=128381264&utm_medium=social&utm_source=twitter&hss_channel=tw-18198832
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