It can be nephritis even if there is no proteinuria. This is because if there is no proteinuria but there is hematuria and it can be confirmed that the amount of hematuria is sufficiently high, usually the second morning urine with >8000/ml of red blood cells. more than 75% of these red blood cells are aberrant red blood cells it is considered to be of glomerular origin and this condition is also called nephritis. Whether it is simple hematuria, hematuria plus proteinuria, or only proteinuria, these are all signs of nephritis. When it is confirmed that the red blood cells are also hematuria, and the morphology of the red blood cells is aberrant, it is more considered a kind of nephritis hematuria, except that this hematuria is the mildest kind of nephritis, called occult nephritis.