This disclosure provides, in one aspect, a method for analyzing a sample from a subject for a biomarker that is indicative of the subject's immune response to β-glucan. Generally, the method includes obtaining a biological sample from a subject, analyzing the sample for a biomarker anti-β-glucan antibody compared to a reference standard, computing a Relative Antibody Unit (RAU) value for anti-β-glucan antibody in the sample, and identifying the subject as biomarker positive if the RAU value is greater than a predetermined RAU value for the biomarker anti-β-glucan antibody.