Correction of Daily Positivity Rates for contribution of various test protocols being used in a pandemic

Abstract

Daily positivity rates (DPR) are a popular metric to judge the prevalence of an infection in the population and the testing response to it as a single number. It has been widely implicated in predicting future course of the SARS CoV-2 pandemic in India. With increasing use of multiple testing protocols with varying sensitivity and specificity in various proportions, the naive calculation loses meaning particularly during comparison between states/countries with large daily variations in contribution of different testing protocols to the testing response. We propose an adjustment to the naive DPR based on the testing parameters and the relative proportional use of each such protocol. Such a correction has become essential for comparing testing response of Indian states from Jun 2020 to Aug 2020 because of steep variations in testing protocol in certain states.

Early warning indicators of COVID-19 burden for a prosilient European pandemic response

“…Various adjustments to the TPR have been proposed, including the inclusion of antigen tests in the denominator, 22 testing parameters and the proportional use of different testing protocols 24 and an adjustment that takes into account the number of persons vaccinated. 22 Vong and Kakkar put forward an adjusted TPR that amends the TPR to reflect the relative increase in cases and the relative increase in tests, and show how it reflects the COVID-19 caseload more appropriately than the TPR.…”