Library · Test
Urine protein test
Make it clearer
The urine protein test usually comes as part of a urinalysis, a lab test used to check the health of the urinary tract: the kidneys, the ureters, the bladder and the urethra.
To understand what protein in the urine means, you have to look at the filter. In the glomerulus, the tuft of capillaries where the kidney filters blood, the basement membrane restricts the passage of proteins according to their size and weight. And that wall has a second barrier as well: its electrical charge is negative, so it holds back proteins that are also negatively charged, such as albumin. Protein in the urine means the filter let through what it was supposed to hold back.
That said, not every finding carries the same weight. Proteinuria is divided into two types: transient, which comes and goes, and persistent, which signals kidney damage. And there are benign causes of proteinuria, meaning causes that are not serious, such as fever and strenuous exercise.
In brief
The urine protein test is usually part of a urinalysis, which checks the health of the urinary tract.
The basement membrane of the glomerular capillary restricts the passage of proteins by size and weight, and the negative charge of that wall holds back negatively charged proteins such as albumin.
Protein in the urine means the filter let through what it was supposed to hold back.
Proteinuria is classified as transient or persistent; persistent proteinuria signals kidney damage, and there are benign causes such as fever or strenuous exercise.
Sources (2)
- MedlinePlus, U.S. National Library of MedicineProtein in Urine, MedlinePlus Medical TestsPublished
- National Center for Biotechnology Information, StatPearls PublishingProteinuria, StatPearlsPublished
This page explains the topic in general terms; it does not tell anyone what treatment to follow.
Updated