Disclaimer: This infographic is not a validated clinical decision aid. This information is provided without any representations, conditions, or warranties that it is accurate or up to date. BMJ and its licensors assume no responsibility for any aspect of treatment administered with the aid of this information. Any reliance placed on this information is strictly at the user's own risk. For the full disclaimer wording see BMJ's terms and conditions: http://www.bmj.com/company/legal-information/ Covid-19 lateral flow tests Calculator for interpreting test results © 2021 BMJ Publishing Group Ltd. Interactive Pre-test probability Likelihood of having covid-19 % Test sensitivity The proportion of patients with covid-19 who have a positive test % Test specificity The proportion of patients without covid-19 who have a negative test % If 100 000 people were tested with these values True positive False positive False negative True negative Lateralflow testpositive Lateralflow testnegative
100% Probability of having covid-19 if test is negative Adjust these values to update graphic below people who test positive have covid-19 100 000 100 000 people who test negative do not have covid-19 person who tests positive does not have covid-19 100 000 people who test negative have covid-19 100 000 Probability of having covid-19 if test is positive 100% have covid-19 100 000 100 000 do not have covid-19 This calculator demonstrates how interpreting a covid-19 lateral flow device (LFD) result varies according to the pre-test probability, and the sensitivity and specificity of the LFD used. LFDs are best for identifying people with active infection. We recommend choosing values for test performance and pre-test probability that reflect somebody having covid-19 and being infectious (see article below).
Please enter a number between 0 and 100 Please enter a number between 0 and 100 Please enter a number between 0 and 100