A method for detecting renal disease or a method for assisting diagnosis of renal disease that is superior in sensitivity and specificity, as well as a kit that can be used therefor is provided. The present invention provides a method for detecting renal disease or a method for assisting diagnosis of renal disease comprising a step of detecting or quantifying free AIM in a biological sample derived from a test subject, as well as a kit for examining or assisting diagnosis of renal disease comprising an antibody that binds to free AIM.