When to Test – Start Calculator

When to Test – Start Calculator


The COVID-19 Testing Impact Calculator uses the following default assumptions for all calculations:

  • A person is contagious for a total of ten days.
  • After becoming infected with COVID-19, 50% of the population in the United States exhibits symptoms.
  • The maximum time between tests is 21 days.
  • Each individual must wait 15 minutes before being sampled.
  • Assumes that the prevalence of COVID-19 inside a company is comparable to that of the general public.

Testing Methodologies

The COVID-19 Testing Impact Calculator uses the following assumptions for test groups:

  • The default assumptions do not apply to any particular test.
  • Tests used for asymptomatic screening are currently used off-label and under practitioner guidance.
  • The default values for each test group are a conservative estimate based on consultation with industry experts due to inadequate data for asymptomatic screening.

Knowing the difference between test sensitivity and test specificity

  • Tests with poorer sensitivity are more likely to produce false negatives, which means they are more likely to miss a true infection by producing a negative test result in people who are infected with COVID-19.
  • A positive result suggests that you are likely to be infected with COVID-19, especially if you are tested within the first week of infection and are symptomatic. Tests with lesser specificity may result in more false positives.

Suggestions are as follows:

  • If you get a negative test result but still have symptoms, quarantine yourself and get a confirmatory test.
  • If you get a positive result and you’re sick, you’re probably infected with COVID-19.
  • If you get a positive result on a test with a specificity of less than 99% and are not symptomatic (asymptomatic), there’s a chance you’re getting a false positive. A confirmatory molecular PCR test should be considered.