Which Rats Are Most Accurate?

There are many different factors to consider when deciding which RAT is the best choice for your lab. For instance, one factor to consider is sensitivity, which is the percentage of positive cases that the RAT can accurately detect. In addition, one factor to consider is the specificity rate, which is the sensitivity of the test compared to the number of positive cases. High sensitivity RATs are those that pick up 91% or more of positive cases. Low sensitivity RATs are those that miss less than 80% of positive cases.

While it may be tempting to use an inaccurate test, this may not be the best option. Although imperfect, these tests can still be used to make important clinical decisions. In particular, RATs that have positive predictive values that are below chance should not be used for one-off testing of individuals who are not at high risk. For instance, a 50% posterior probability of SARS-CoV-2 positivity is a low-precision RAT result.

Positive predictive values ranged from 38% to 100% when the prevalence of the disease was 1% or higher. Positive predictive values were also higher in patients who were symptomatic. In contrast, negative predictive values were uniformly 99%.