Kidney School™—a program of Medical Education Institute, Inc.

Module 7—Understanding Kidney Lab Tests

Cracked egg

Albumin is a kind of protein that can be measured in the urine. (Egg whites are one type of albumin.) The test for albumin, or urine protein, measures how much protein passes through the kidneys and into the urine. Protein is a big molecule—too big to fit through the tiny blood vessels in healthy kidneys.

This means that finding protein in the urine is a sign that the kidneys are damaged. The tiny blood vessels are "leaky" and big protein molecules are slipping through.

Protein in the urine is a very important sign of kidney disease. A dipstick is usually used to measure protein.

Studies of people with diabetes show that kidney disease starts slowly, even before protein can be found in the urine with a dipstick.

Microalbuminuria means very tiny amounts of protein. It is a very sensitive measure of protein in the urine.

The good news is, when microalbuminuria is found, it can be treated with any one of several classes of blood pressure drugs. Using these drugs can slow down the rate of kidney disease, sometimes for years. Each person with diabetes should have a microalbuminuria test at least once a year. This test can be done on a single urine sample or a 24-hour urine collection.

There is another way to measure whether there is too much protein in your urine. You give one sample of urine in a cup, and it is tested for both protein and creatinine together. This is called the albumin-to-creatinine ratio. Looking at this ratio is more convenient than having you do a 24-hour urine collection. And it is accurate, even if you have had more or less fluid to drink.

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