How likely it is that someone will test positive with COVID-19 a few days after developing symptoms? Useful preliminary analysis by @LourencoJML et al https://www.medrxiv.org/content/10.1101/2020.04.05.20053355v1.article-metrics

The authors estimated that in a single test of some who first had symptoms 10 days ago, there's a 33% chance of a false negative with a nasal swab, and 53% chance with a throat swab.