Provided is a method that involves the detection of protein antigen (PA) and/or collagen-binding protein (CBP) of oral cavity bacteria in a sample, and in which oral cavity bacteria that exacerbate hemolysis are detected for and/or subjects at high-risk for hemolysis aggravation are screened and/or the level of risk of the hemolysis aggravation in a subject is assessed if a PA is not detected and/or a CBP is detected in the sample. Also provided are a detection reagent and kit for use in the method.
