1/ Has anyone seen data on the testing specs for rtPCR (sensitivity/specificity) in asymptomatic/presymptomatic #covid19 patients?

This is critical-- but if there is low sensitivity/high false negative in this patient population, then obviously an issue.

More thoughts below:

2/ We know from some limited data that viral load is similar early in the course in both symptomatic/asymptomatic patients. @NEJM

https://www.nejm.org/doi/full/10.1056/NEJMc2001737

3/ We also have data suggesting that viral replication is high early on in the upper respiratory tract.

Over time, that replication decreases there, & increases in the lower respiratory tract (shedding viral RNA from sputum well after symptoms)

@nature
https://www.nature.com/articles/s41586-020-2196-x_reference.pdf

4/ So theoretically, the sensitivity for picking up cases using rtPCR from NP/OP swabs is reduced later in disease course - but hard to know where you are if you are asymptomatic or have disease that is so mild that you didn't present right away for testing/ don't remember onset.

5/ I'm sure people have thought this through more. Please share any understanding or data you have.

cc @RanuDhillon @IngridKatzMD @AaronRichterman @FranciscoMarty_ @s_keshavjee @paimadhu @sri_srikrishna @amymaxmen @michaelmina_lab @HelenBranswell @carlzimmer @ericashenoy

thread/question on rtPCR sensitivity in presymptomatic/asymptomatic- any leads would be helpful

cc @florian_krammer @angie_rasmussen @hewlett_angela @UNMC_ID @edyong209 @juliaoftoronto @KrutikaKuppalli @CarlosdelRio7 @CT_Bergstrom @CarolineYLChen @gregggonsalves

thread/question on rtPCR sensitivity in presymptomatic/asymptomatic- any leads would be helpful
@sciencecohen @kakape @JenniferNuzzo @DrJRMarcelin @KellyCawcuttMD @mugecevik @SaskiaPopescu @jflier @choo_ek @EricTopol @trvrb @mlipsitch much appreciated, thank you in advance