Albumin in the urine (albuminuria): is it serious?

Albumin is a protein found in large quantities in the blood.. She alone represents 60% of blood proteins, and is therefore the most important of them. But normally, it is not found in the urine. When it does, it signals kidney dysfunction. We speak then albuminuria. How to test albumin in urine? How interpret their results? What does high albuminuria mean? And a low rate?

Definition: what is albuminuria?

Albumin is a protein found in large quantities in the blood. She alone represents 60% of blood proteins, and is therefore the most important of them. But normally, it is not found in the urines. When it does, it signals kidney dysfunction. This is called albuminuria. “Albumin is not the only protein that can be found in the urine in the event of pathologyexplains Dr. Romain Troalen, general practitioner. In general, we then make a proteinuria to find them all.” These are mainly found in cases of kidney disease or diabetes. But they can be complicated by an edematous syndrome, corresponding to the accumulation of water in the interstitial sector (space located between the vessels and the tissues and often visible by swelling of the dependent areas, ankles and legs). When the presence of albumin in the urine is low, but slightly above normal, it is called microalbuminuria.

albuminuria or proteinuria, is done on an empty stomach. “There are two ways of measuringr, explains Doctor Romain Troalen. Via urine dipsticks, and via 24-hour proteinuria.” For him “The use of strips is only a track. If it is positive, it is absolutely necessary to do a more thorough urine analysis”. In this case, the search for albumin in the urine is done in the laboratory, on a first morning urination samplethen on a collection of urine carried out for 24 hours.

“In most cases, albuminuria is detected by chance”

Why have albuminuria?

The search for albumin in the urine makes it possible to easily detect kidney disease, which cause few symptoms until an advanced stage. “In most cases, albuminuria is detected by chance during a test at occupational medicine, for example”, says Dr. Troalen. The search for albumin in the urine is carried out punctually when the doctor suspects various pathologies such as pancreatitis, high blood pressure or diabetes.

“Between 30 and 300 mg/24 hours, we are faced with a microalbuminism. If we exceed 300 mg / 24 hours, then there, it is very high, and we must quickly do additional examinations “explains the doctor.

What is elevated albuminuria?

When a high level is detected on the first test, it does not mean with certainty that there is a serious lesion of the kidney. Doctor Troalen advises first to check that it is not a false positive. Proteins can be highly concentrated in the urine due to Urine pH too high, or if there is blood in the urine. You have to recheck 15 days later, or do another test 24 hours later. This one, if it is coupled with urinary creatinine assay (another protein) over 24 hours, can point to the probable cause of proteinuria. Further laboratory tests will then be required. “Nevertheless, when there is a very high albuminuria, more than 3 g/24 hours, then you have to quickly an opinion from a nephrologist (kidney specialist)”warns Dr. Troalen. “When you have a patient with a family history, hypertension or diabetes, proteinuria over 1 g / 24 hours must also be taken care of quickly.” In fact, large quantities of albumin are found in the urine in the event of a serious lesion. This is usually a process that spans several years, such as in diabetic patients: small amounts of albumin pass through the urine first, due to small changes in the kidney filter. Then these modifications worsen and the quantities present are more and more important.

What does high albumin mean during pregnancy?

In pregnant women, “it is normal for the albumin level to double or triple“, explains Dr. Troalen. It can show up to 200 mg/24 hours without one having to worry. Nevertheless, the albumin level is regularly checked in pregnant women to avoid any risk. In effect, if the test is very high (exceeds 300 mg/24 hours) additional examinations must be carried out quickly to find the associated pathology, which may be a risk for the unborn baby: “A high albumin level may be a sign of pre-eclampsia (also called “toxemia of pregnancy”), which is the association of hypertension and edema which, added to proteinuria, gives a risk of intrauterine growth retardation, or even a risk in very rare cases if it is not supported, of death in utero.

What does low albuminuria mean?

“If it’s less than 30 mg/24 hours, then there’s no problem, since albumin is not supposed to end up in the urine”, recalls the general practitioner. Nevertheless, there may be false negatives if the other proteins are poorly detected, or if the urine is too dilute. What to do ? There is nothing to do if the rate is low, except when a pathology is suspected, then it will be necessary to request a specific search or redo the tests.

Thanks to Dr Romain Troalen, general practitioner.