The characteristics of mixed proteinuria, including large, medium and small molecule proteinuria, indicate that glomerular as well as tubular damage is caused, which generally represents a more serious condition. 1. Glomerular injury: common in glomerular disease, usually produce medium and large molecule proteins in urine, large molecule proteins such as IgG, C3, medium molecule proteins such as albumin. 2. Tubular injury: common in tubulointerstitial diseases, such as hypertensive nephropathy, interstitial nephritis, etc., mostly manifested as small molecule proteinuria, such as β2microglobulin, α1microglobulin and so on. Mixed proteinuria refers to the presence of large, medium and small molecule proteinuria, generally suggesting that the lesion involves the glomerulus and tubules, considering the seriousness of the condition, the need for timely consultation in a regular hospital, standardized treatment under the guidance of physicians.