The diagnosis of IgA nephropathy relies on pathological examination. The name "IgA nephropathy" itself is a term used in immunopathological diagnosis, describing a type of chronic glomerulonephritis. There are many reasons that can cause inflammatory reactions in the kidneys, and the underlying mechanisms of the disease vary. Specifically, IgA nephropathy refers to the abnormal deposition of IgA immune complexes in the mesangial areas of the glomeruli. Therefore, a pathological examination is necessary for diagnosis. Typically, under a light microscope, proliferation of mesangial cells and widening of the mesangial areas can be observed. Additionally, immunofluorescence testing is conducted to detect a large presence of IgA immune complexes in the glomerular mesangial areas, confirming the diagnosis of IgA nephropathy.