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Evaluation of proteinuria in children

Olivia Gillion Boyer, MD, PhD
Section Editors
Patrick Niaudet, MD
Jan E Drutz, MD
Deputy Editor
Melanie S Kim, MD


Proteinuria as a marker of renal disease has been well established. The dilemma that faces the primary care clinician is to differentiate the child with transient or other benign forms of proteinuria from the child with proteinuria from renal disease.

An overview of the evaluation of proteinuria in children will be presented here. Some related issues, including the mechanisms of proteinuria, are discussed in more detail elsewhere. (See "Assessment of urinary protein excretion and evaluation of isolated non-nephrotic proteinuria in adults".)


Normal protein excretion — Urinary protein excretion in the normal child is less than 100 mg/m2 per day or a total of 150 mg per day. In neonates, normal urinary protein excretion is higher, up to 300 mg/m2, because of reduced reabsorption of filtered proteins.

Approximately one-half of normal protein excretion consists of proteins secreted by tubular epithelium, mostly Tamm-Horsfall protein (uromodulin). The other half consists of plasma proteins including albumin, which accounts for approximately 40 percent of the total urinary protein, and low molecular weight (LMW) proteins, such as beta-2 microglobulin and amino acids.

The normally low rate of urinary protein excretion is due to two factors:

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Literature review current through: Nov 2017. | This topic last updated: Jun 19, 2017.
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