What laboratory finding is characteristic of IgA nephropathy?

The characteristic laboratory finding of IgA nephropathy is gross hematuria that often occurs following an upper respiratory infection (URI). In IgA nephropathy, which is also known as Berger’s disease, the deposition of IgA immune complexes in the mesangial cells of the glomeruli leads to glomerular inflammation. Following a respiratory or gastrointestinal infection, patients frequently present with hematuria as a result of this immune-mediated process.

Hematuria can be microscopic or gross, but in this context, gross hematuria can be particularly prominent and is often a key clinical feature that helps distinguish IgA nephropathy from other forms of glomerulonephritis.

The other potential laboratory findings listed do not align as directly with the pathophysiology or typical presentation of IgA nephropathy. Low complement levels are more characteristic of conditions such as post-infectious glomerulonephritis or lupus nephritis. Segmentation of red blood cells may indicate a microangiopathic hemolytic anemia, and elevated uric acid levels are not specifically associated with IgA nephropathy but could suggest other conditions, such as gout or renal impairment.