The impact of false positive COVID-19 results in an area of low prevalence
Public Health England reports that RT-PCR assays show a specificity of over 95%, meaning that up to 5% of cases are false positives.2 The impact of false positive results includes risk of overestimating the COVID-19 incidence, the demand on track and trace, and the extent of asymptomatic infection.
假陽性5%，計算方法？
During the same period, there were 5,079 negative tests; thus a total of 5,110 tests were carried out. The false positive rate (single gene low level positive) in this period was 0.5% (26/5110), giving a specificity of 99.5% (5,079/5,105). Over the same period, the true positive rate was 16% (5/31). From this data collected in a very low prevalence setting, the negative predictive value was 100% (no identified false negative results) and the positive predictive value was 16% (5/31).
拜托假陽性up to 5%已經夠高了。
