For the study, the researchers developed their own antibody test. They then used it to compare the performance of 10 commercial antibody test kits on an identical panel of 110 positive blood samples from hospitalized COVID-19 patients, and 50 pre-pandemic coronavirus-negative blood samples. … Specificity -- the ability to correctly identify those without the disease -- ranged from 82% to 100%. Overall sensitivity -- the ability to correctly identify those with the disease -- ranged from 61% to 87%.