Physiological
- Functional, such as intense exercise, fever, leading to protein breakdown
- Positional
Pathological
- Glomerular proteinuria: damage to the glomerular basement membrane
- Selective proteinuria: damage to the charge barrier, mainly albumin (medium molecule) and small molecules, commonly seen in minimal change disease
- Non-selective proteinuria: damage to the mechanical barrier, including globulins (large molecules) + albumin + small molecules, seen in various primary and secondary glomerular diseases
- Tubular proteinuria: tubular dysfunction, unable to reabsorb small molecules in the primary urine (such as β_2 microglobulin, ribonuclease, lysozyme), seen in pyelonephritis, interstitial nephritis, renal tubular acidosis, toxic nephropathy (heavy metals like mercury, tin, bismuth and use of gentamicin, kanamycin, polymyxin, etc.), post kidney transplantation, etc.
- Overflow proteinuria: normal tubules, but excessive small molecules in the primary urine
- Small molecule light chain proteins ([[Bence-Jones Protein BJP]]): such as in multiple myeloma, where大量浆细胞 in bone marrow release antibodies (composed of light chains + heavy chains, light chains being Bence-Jones proteins)
- Hemoglobin: hemolytic reaction
- Myoglobin: skeletal muscle crush injury, large area myocardial infarction
- Increased tubular secretion: excessive tubular secretion of T-H proteins
- Others
- Tissue proteinuria
- Pseudoproteinuria
24-hour Urine Protein
Less than 1 g indicates a small amount of proteinuria
Between 1-3 g indicates a moderate amount of proteinuria
Greater than 3 g indicates a large amount of proteinuria