Abstract: A problem to be solved by the present invention is to provide a method of assisting diagnosis of the health condition of a subject by correcting variation in an amount of a collected disease marker, which is caused by variation in the skin barrier function of the subject, and acquiring information reflecting the health condition of the subject accurately, and to solve the problem, the present invention provides a method of assisting diagnosis of a disease in a subject using a disease marker and a reference marker, the method including: applying, to a skin surface of the subject, a sheet capable of generating an attractive force due to electrostatic interaction between the sheet and each of the disease and reference markers; detaching the sheet from the skin surface; measuring the amount of each of the disease and reference markers that are attached to the sheet; and acquiring information on the disease in the subject based on a value obtained by correcting the measured amount of the disease marker with the me