The FDA is at risk of de-listing the "move knife" data for COVID-19 antibody detection products.

The outbreak of new crown pneumonia is still spreading, as of 13 o'clock today, the global total of more than 3.82 million cases confirmed, more than 1.26 million confirmed cases in the United States.
the outbreak is unprecedentedly severe, governments are urgently authorizing potential drugs/therapies for the treatment of severe new coronary pneumonia.
and before treatment, it is important to accurately identify the target patient, which facilitates the concentration of current highly stressful medical resources in the treatment of patients with new coronary pneumonia.
recently, the FDA began to "move the knife" on the less accurate COVID-19 diagnostic kit, and diagnostic products from Ortho-Clinical Diagnostics and BD were at risk of being de-marketed.
The FDA has so far granted emergency use authorizations (EUA) to 10 antibody testing products that test blood samples to assess the presence of antibodies against the new coronavirus (SARS-CoV-2), according to evaluate Pharma, a pharmaceutical market research firm.
the evidence supporting these antibody testing products is uneven in quality, and some companies sell antibody testing products in the U.S. in full legal terms, but do not provide any data on accuracy at all.
now, the FDA is finally taking action on the situation.
Monday, the agency said developers must provide accuracy data within the next 10 days or risk being delisted.
, the FDA has developed exact criteria that antibody testing products must meet.
and based on current evidence, some antibody testing products do not meet the requirements.
, the agency did not require data accuracy to award an antibody testing product, EUA, and developers did not have to sell their testing products in the U.S. by obtaining EUA.
, for example, obtained EUA for its antibody-testing product on April 26, but actually began selling it in the U.S. on April 15.
, it's unclear how many antibody-testing products are on sale in the U.S., but there could be hundreds of them, according to the report.
but that will soon change.
the FDA said that "the cautious balance of risks and benefits has shifted from mid-March levels" and that the agency has revised its policy and listed the types of evidence needed to allow COVID-19 antibody testing products to continue to be sold.
FDA did not use sensitivity and specificity, but instead used the terms positive and negative percentage consistency (PPA and NPA).
these values are calculated in the same way as sensitivity and specificity, but used when the control test product is considered imperfect.
in this case, the best possible control is PCR testing for coronavirus RNA, which is not yet recognized as a clinical reference standard.
standards for antibody testing products Specifically, the FDA notes that data supporting COVID-19 antibody detection products are at least 90% PPA (equivalent to sensitivity) and NPA (equivalent to specificity) is at least 95%.
for testing products that specialize in reporting IgM and IgG results, IgM and IgG require PPA to be at least 70% and 90%, respectively.
agency also stipulates that at least 30 antibody-positive samples and 75 antibody-negative samples should be used to provide clinical consistency data.
table below summarizes the accuracy data of some known antibody test products sold in the United States.
important warning is that the data relies on information published by companies, and in some cases by dealers or academic researchers.
these companies are likely to have better data, but keep them secret, although it is unclear why.
table above, some antibody detection products do not meet FDA sensitivity/PPA or specific/NPA standards, such as The Covid-19 IgM/IgG Rapid Detection Kit, developed by Biomedomics and sold by BD.
other testing products are not up to standard in the sample size that is tested, such as Epitope Diagnostics' IgG Elisa kit, which is only validated in a small sample, while CTK Biotech claims that its testing products are accurate enough, but does not provide sample size information.
addition, the FDA has developed a separate program with the U.S. Centers for Disease Control and Prevention (CDC) and the National Institutes of Health (NIH) to double-check the accuracy of tested products sold in the U.S.
, the FDA said it had investigated 13 testing products so far and that the data was still under review.
, the FDA recently released an umbrella EUA for antibody testing products that have completed this validation process, and will announce in the future which testing products have met the standards.
source: FDA Clamps down on Covid-19 antibody tests.