Abstract: The purpose of the present invention is to provide: a method for testing the aggravation risk for a person infected with the COVID-19 virus, the method allowing the use of urine as a test sample; a test kit for the method; and a companion diagnostic drug and an aggravation risk marker thereof. The present invention is a method that includes a step for determining the amount of liver fatty acid binding protein in urine sampled from a subject, and that tests the aggravation risk of SARS-CoV-2 infectious disease (COVID-19) on the basis of the quantitative determination result.

Abstract: Disclosed is a method for assisting prediction of exacerbation of respiratory infection, comprising measuring a biomarker in a specimen collected from a subject suffering from a respiratory infection or a subject suspected of having a respiratory infection, wherein the biomarker is at least one selected from the group consisting of IFN?3, CCL17, CXCL11, IP-10, IL-6 and CXCL9, and a measured value of the biomarker is used as an index to predict exacerbation of the respiratory infection.