There are many reasons which can cause protein in urine. We should consider from the following aspects.
1. It is caused by renal glomerular damage such as acute renal glomerular nephritis, lupus nephritis, purpura nephritis, diabetic nephropathy, tumor, renal artery sclerosis, nephrotic syndrome.
2. It is caused by renal tubules such as pyelonephritis, damage of renal parenchyma and rejection after kidney transplant.
It can also be caused by protein which spills out such as acute hemolysis, myeloma multiplex, macroglobulinemia.
3. Tissue protein such as inflammation in kidney, poisoning and so on.
4. Others such as chronic kidney failure, diabetes, lupus nephritis.
