Proteinuria: is the protein in urine dangerous?

Normally, there is a small amount of protein present in the urine. When the amount of protein present in the urine rises to higher than normal amounts, it is called proteinuria.

Normal adults may urinate up to 150 mg of protein per day and interestingly enough, in adolescents, this may be as high as 250 mg/day. Higher amounts of protein may appear in our urine after strenuous exercise or while we are ill with a variety of common illnesses. This type of proteinuria will quickly disappear and is of no consequence. In one large study of healthy school children between six and 12 years of age, about 3% had mild proteinuria at some time or another and about five children per thousand had abnormal amounts of protein in urine on each of three separate occasions. Nephrotic syndrome, a group of conditions in which urine protein is particularly high, occurs in about 1-2 per 100,000 children below the age of 16.

What causes it?

About 25% of all the blood the heart pumps every day flows through the kidneys. There, the blood is filtered through small vessels called glomeruli. Normally, the” filtering slits” in these glomeruli are big enough to let water and waste products through, but small enough to keep the red blood cells and almost all the protein in the bloodstream. Proteinuria can be caused by changes in the size of these filtering slits or by the illness that damaged the kidney and its glomeruli. Other causes of proteinuria include medications that may damage the kidney or be born within an abnormally shaped or functioning set of kidneys. One common cause of proteinuria in adults is long-standing diabetes mellitus.

What are the symptoms?

People who have moderate amounts of protein in their urine may have no symptoms whatsoever. Those with large amounts of protein in their urine may develop swelling around their eyes, their abdomen, or their feet. This is due to water retention and will cause them to gain weight and perhaps feel more tired than usual. The large amounts of protein in their urine may cause abnormal amounts of bubbles to be present in the toilet after they urinate. Occasionally, these people may retain enough fluid so that it goes to their lungs and causes difficulty breathing.

How is it diagnosed?

Proteinuria is diagnosed by examining the urine. The first test your doctor may do it is a simple urinalysis. Normal urine has very small amounts of protein present. Larger amounts are usually reported as 1+ to 4+. To confirm this test, your doctor may send a sample of your urine to the laboratory to measure the actual amount of protein present. Occasionally your doctor will ask you to collect a timed sample, often 24-hours, to learn how much protein you excrete each day.

How to prepare for the diagnosis

All urine is collected during the day in a clean container with a volume of 2-3 liters.

On the eve of the test (in the evening), the container for collecting urine must be rinsed from the inside with boiling water, turned over, and left until morning.

In the morning after sleep, you need to urinate in the toilet. All urine is then collected over a 24-hour period (including the morning portion the next day!).

In the morning, the urine collected during the day is mixed and about 100 ml is taken into a special container for collecting urine.

In patients who test positive for protein in the urine, routine microscopic examination of urine should be done. Abnormal urinalysis (eg, abnormal red blood cells indicating glomerulonephritis; glucose or ketone bodies indicating diabetes mellitus) or diseases suspected based on history and physical examination require further evaluation.

If other indicators of the urinalysis are normal, further studies may be postponed until the re-determination of the presence of protein in the urine. If proteinuria is not detected on re-examination, it is likely to be functional. Persistent proteinuria is a sign of glomerular pathology and requires additional examination and referral of the patient to a nephrologist.

The collected analysis and referral to the sentry nurse.

The direction must indicate the total amount of urine collected per day.

What is the treatment?

The treatment of proteinuria depends upon the amount of protein excreted and upon its cause. There are many reasons for having proteinuria and treatments vary, depending upon the specific cause. Your doctor will need to perform other tests, generally, blood tests as well as X-ray or ultrasound tests, to determine the cause of proteinuria. Small amounts of protein the urine may not need any therapy at all. Patients with large amounts of protein in their urine will probably need medication both to improve or stabilize the kidney function and to help them deal with their weight gain and swelling.

Self-care tips

High levels of proteinuria almost always indicate a renal problem. Proteinuria may be the first sign of renal disease and control of proteinuria has been shown to help maintain kidney function. Individuals who develop the symptoms of proteinuria or who are told that they have abnormal amounts of protein in their urine on screening tests should have their kidney function evaluated by their physician.


The article is written by licensed urologists: Dr. David M. Kaufman and David M. Weiner, MD. If you have any questions after reading the article, you can contact us by asking a question in the feedback form

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