Proteinuria

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Name of Symptom/Sign:
**Proteinuria**
*Classifications and external resources*
ICD-10	R 80.
ICD-9	791.0

Proteinuria (from protein and urine) means the presence of an excess of serum proteins in the urine. The protein in the urine often causes the urine to become foamy although foamy urine may also be caused by bilirubin in the urine (bilirubinuria)[1],retrograde ejaculation [2], pneumaturia (air bubbles in the urine) due to a fistula[3], or drugs such as pyridium [4]. Proteinuria is often diagnosed by a simple dipstick test although it is possible for the test to give a false negative even with nephrotic range proteinuria if the urine is dilute[5]. False negatives may also occur if the protein in the urine is composed mainly globulins or Bence-Jones Proteins because the reagent on the test strips,Bromphenol blue, is highly specific for albumin [6][7]. Anyone with foamy urine should be more thoroughly evaluated with more sensitive tests such as a 24-hour urine collection test or Protein electrophoresis even if the dipstick is negative for protein to completely rule out proteinuria[8][9].

Proteinuria may be a sign of renal (kidney) damage. Since serum proteins are readily reabsorbed from urine, the presence of excess protein indicates either an insufficiency of absorption or impaired filtration. Diabetics may suffer from damaged nephrons and develop proteinuria.

With severe proteinuria, general hypoproteinemia can develop which results in diminished oncotic pressure. Symptoms of diminished oncotic pressure may include ascites, edema, and hydrothorax.