SF C19 antibody testing update: lots of mixed data due to non-conformity to testing parameters. improving checks on how we are getting tests out and results back. here is where data stands as of tonight:
338 tests, 7 positive, 20 inconclusive, 311 negative. HOWEVER, 3 of 7 positives were already PCR+ coronavirus patients (should've been excluded) and remaining 4 live outside SF. here are SF-only statistics:
258 tests, 0 positive, 14 inconclusive, 244 neg. age distribution: <23 0%, 24-30 10%, 31-40 42%, 41-60 46%. 60+ 2% (not a good fit for overall city demo data); no data from bayview/hunters pt, sea cliff, richmond districts (not ideal); odds of finding asymptomatic people by now:
340/840k SF residents are reported positive-0.04%. if we assume 0%,50%,80%,90% of people with c19 are asymptomatic (what we're looking for here), the odds of finding just ONE positive with ONLY 258 tests is 9%, 18%, 39%, and 63% respectively... so its early! next steps:
we are going to try to test 1000 total SF residents. issues we are having include getting adequate response rates (ppl take tests & dont distribute or dont take or dont report), distribution amongst tech/doctor/science communities not representative of SF geo/demo...
we are also seeing issues with sensitivity of the two test kits we've been using - wandfo and raybiotech. we've seen cases of recent PCR+ patients test negative for IgG, IgM, or both. this is explained in several papers but also highlights the risks of using these test kits ...
the sensitivity of these different test kits has not been widely validated. we will share our data of testing against PCR+ patients. UCSF conducting a large-scale testing of seropositive patients which will help inform these sorts of efforts. ok, we'll keep going & keep reporting
