tubular proteinuria
Proteinuria characterized by the presence of low-molecular-weight proteins due to impaired tubular reabsorption rather than glomerular damage.
Full Definition
Tubular proteinuria occurs when the renal tubules fail to reabsorb normally filtered low-molecular-weight proteins, resulting in their excretion in urine. Unlike glomerular proteinuria which features albumin and larger proteins, tubular proteinuria typically contains β2-microglobulin, retinol-binding protein, and lysozyme. In pediatric patients, this pattern may indicate tubulointerstitial disease, drug toxicity, or hereditary tubular disorders. The total protein excretion is usually lower than in glomerular diseases, typically less than 2 grams per day. Diagnosis requires protein electrophoresis or specific assays for tubular proteins, as standard dipstick tests may be negative or only mildly positive.
Usage
Usage note: Specify the type of proteinuria when documenting; standard dipsticks may not detect tubular proteins effectively.
In Context
- "Urine electrophoresis revealed tubular proteinuria with elevated β2-microglobulin levels." — Laboratory interpretation
- "The pattern of tubular proteinuria suggested underlying tubulointerstitial nephritis." — Nephrology consultation