# False negative rate of PCR

## Source 1
https://www.acpjournals.org/doi/full/10.7326/M20-1495

False negative rate (top) and posterior probability of being infected given a negative result and assuming a probability prior of infection upon contact of 11.2% (bottom) as a function of days since exposure.

Same posterior probabilities as bottom figure above but for different infection probability priors.

Limitations with this source:
- it is a metareview and modeling based on 7 papers but for which they have too little data for the presymptomatic phase
- they mix tests done with nasopharyngeal with oropharyngeal swabs and unclear specimen source swabs; nasopharyingeal seems to be according to other authors slightly more sensitive

Data used for this study

## Source 2
https://www.medrxiv.org/content/10.1101/2020.04.05.20053355v3

1-p(false negative) as a function of days since symptom onset

Limitations:
- it is not informative regarding the pre-symptomatic phase nor regarding the asymptomatic cases...

## Source 3
https://www.medrxiv.org/content/medrxiv/early/2020/11/04/2020.11.01.20223107.full.pdf