Anti-HCVAg positivity is one of the symptoms that confirm the diagnosis of noncryoglobulinemic MPGN (membranoproliferative glomerulonephritis) as well as membranous nephropathy. Hepatitis C virus (HCV) is a single-stranded RNA virus that was first identified in 1989 and is now estimated to affect approximately 100 × 106 people worldwide, mainly through blood product transmission and intravenous drug use. The relationship between HCV infection and glomerular diseases has gradually increased in the last decade, and it is now believed that HCV-related kidney damage mainly includes cryoglobulinemic MPGN, noncryoglobulinemic MPGN, and membranous glomerulopathy (MPGN). membranous nephropathy (MN). The following diseases are also causes of anti-hcvag positivity: 1, hematuria Hematuria refers to ≥ 3 red blood cells per high-powered microscopic field in centrifuged precipitated urine, or more than 1 or 1 hour urine red blood cell count more than 100,000 or 12 hour urine sediment count more than 500,000, all indicate an abnormal increase of red blood cells in urine, and is a common urological symptom. 2.Cryoglobulinemia Cryoglobulinemia (cryoglobulinaemia) is a series of skin and systemic symptoms produced by cold globulin deposition under low temperature conditions, thus causing impaired blood circulation. 3, nephrotic syndrome “nephrotic syndrome” (NS) for short, refers to a group of syndromes caused by a variety of etiologies, with increased glomerular basement membrane permeability with reduced glomerular filtration rate and other glomerular lesions. 4, hepatitis C virus infection and glomerulonephritis hepatitis C virus (HCV) is a single-stranded RNA virus, first discovered in 1989, now estimated that there are about 100 * 106 infected people worldwide, mainly through blood products and the use of intravenous drug transmission. The relationship between HCV infection and glomerular diseases has gradually increased in the last decade, and it is now believed that HCV-related kidney damage mainly includes cryoglobulinemic MPGN, non-cryoglobulinemic MPGN, and membranous glomerulopathy. membranous nephropathy (MN). 5, cryoglobulinemia kidney damage Cryoglobulin (cryoglobulin) is a type of globulin that precipitates or jellies when the plasma temperature drops to 4-20°C, and dissolves when the temperature rises to 37°C. Normal serum contains only trace amounts of cryoglobulin, and when its concentration exceeds 100 mg/L, it is called cryoglobulinemia (cryoglobulinemia). Increased serum cryoglobulin is often accompanied by glomerular lesions, called renal damage due to cryoglobulinemia.