From the Stanford Daily:
By Kate Selig on April 5, 2020
Over 3,200 people in Santa Clara County were tested for COVID-19 antibodies on Friday and Saturday in an effort to determine the proportion of the population that either has or has recovered from coronavirus. The study, led by researchers at Stanford Medicine, is the first of its kind in the nation.
The results, expected to be released within a week, could be used to guide future public health policy in the county, according to associate professor of medicine and study co-lead Eran Bendavid.
“It’s hard to stand up in this epidemic and say, ‘Look, we really don’t know if this epidemic is impending Armageddon,’” Bendavid said. “In order to know and reduce that uncertainty, you need numbers.”
COVID-19 antibody tests differ from nasal swab tests currently employed by healthcare providers both in method and results. Nasal swab tests take samples from the back of the throat — leading some to characterize the experience as “being stabbed in the brain” — and determine whether live coronavirus is present in the body. The antibody tests used in the Stanford study, which were supplied by Premier Biotech, require only a fingerstick of blood and test for IgM and IgG antibodies that indicate that a person either has coronavirus or had it and recovered.
Widespread antibody testing is also taking place in Colorado’s San Miguel County, where all residents will be provided with tests donated by United Biomedical executives who live in the county. Another coronavirus seroprevalence study will be conducted in Los Angeles next week, according to Bendavid.
So results should be out by the end of this week or early next week.
Unfortunately, the Telluride, Colorado test has bogged down in processing because the lab is in New York, where 40% of workers are out. Here are the results so far:
1,631 tests have been processed
8 were positive
25 were indeterminate (borderline)
1,598 were negative
A big study of thousands of blood donations in six U.S. cities is also underway. The Seattle data has been processed but not released yet, with New York City being processed. Blood donors tend to be healthier than the local average.
How accurate antibody tests are in terms of false positives and false negatives is another question. And do all people infected develop antibodies? Time will tell.