COVID Variant Test Slide (IMAGE) Duke University Caption A new test can quickly test the ability of antibodies to neutralize spike proteins from different variants of COVID-19 simultaneously. The D4 assay shown here is the Teflon-like technology that makes the test possible. Credit Duke University Usage Restrictions None License Original content Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.