Method and device for diagnosing organ injury

A method of treating an acute kidney injury (AKI) in a human subject, the method comprising:

• (A) having a vesicle-containing sample obtained from said human subject sent to a laboratory for the laboratory to perform an assay comprising the following steps (1)-(3):
• (1) capturing at least a portion of vesicles from said sample on or in a vesicle-capture material, thereby generating a vesicle sample;
• (2) quantifying an expression level of at least one gene in said vesicle sample, wherein said at least one gene comprises CALM1 and at least one additional gene selected from the group consisting of SLC12A1, CFLAR, GSTA1, HIF1A, and ALB;
• (3) determining that said subject has said AKI due to said expression level of each of said at least one gene being significantly different from the expression level of the respective gene in a vesicle sample of a healthy human control subject not suffering from said AKI, thereby diagnosing said subject as having AKI;
• and
• (B) administering an effective amount of an AKI medication to the human subject having said AKI, wherein said AKI medication is selected from the group consisting of a diuretic agent, an intravenous fluid, a steroid medication, a plasma exchange, and a cyclophosphamide, thereby treating said AKI in said human subject.