05/06/2024
Albuminuria (proteinuria)
Albuminuria (sometimes referred to as proteinuria) is when you have albumin in your urine. Albumin is an important protein normally found in the blood that serves many roles in the body - building muscle, repairing tissue, and fighting infection. It is not usually found in the urine.
Healthy kidneys stop most of your albumin from getting through their filters and entering the urine. There should be very little or no albumin in your urine. If your kidneys are damaged, albumin can “leak” through their filters and into your urine.
Albuminuria (proteinuria) is not a separate disease. It is a symptom of many different types of kidney disease and a significant risk factor for complications. Having albumin in your urine can be a sign of kidney disease, even if your estimated glomerular filtration rate (eGFR) is above 60 or “normal”.
Signs and symptoms
Most people with albuminuria (proteinuria) may not notice any symptoms. This is why it is so important to get regular health checkups (including lab tests), especially if you have any risk factors for albuminuria or kidney disease.
If symptoms are present, you may notice one or more of the following:
Foamy urine
Puffiness around the eyes (especially in the morning)
Frequent urination (p*eing more often than usual)
Swelling of your feet, ankles, belly area, or face
Causes
Albuminuria (proteinuria) is caused by kidney damage, specifically when the damage occurs in the glomerulus (the kidney’s filter). Sometimes this is temporary (short-term damage), while other times it is chronic (long-term damage). The exact cause for the kidney damage is different for each person and may even be due to several factors combined.
Some of the most common causes of temporary (short-term) albuminuria include:
Dehydration (not drinking enough water)
High-intensity exercise
Fever and/or infection
Heart failure exacerbation (flare-up)
Some of the most common causes of chronic (long-term) albuminuria include:
Diabetes (especially if your blood sugars are higher than your target range)
Hypertension (high blood pressure)
Heart disease and/or heart failure
Glomerular disease (such as IgA nephropathy, lupus nephritis, focal segmental glomerulosclerosis (FSGS), or glomerulonephritis)
Having albuminuria may not always mean you have actual kidney damage. This is why repeat testing is so important – to help tell the difference between chronic (long-term) kidney damage and temporary (short-term) stress on the kidneys.
Types
You may have heard or read about the words “microalbuminuria” and “macroalbuminuria”. These words were used in the past to help describe categories for how high a person’s urine albumin-creatinine ratio (uACR) level is. However, these separate words are no longer recommended - they add confusion without providing any extra benefit. Newer research has shown that any uACR level above the goal range is a risk factor for complications. Any level above 30 mg/g is now called “albuminuria” (instead of using two separate terms).
Complications
Albuminuria is a significant risk factor for developing complications. Some of these complications include:
Kidney failure
Cardiovascular disease (heart failure, heart attack, or stroke)
Heart failure
Decreased life expectancy (early death)
Your risk for getting these complications is directly connected with your uACR level. This means a higher uACR level comes with a higher risk for developing one or more of these complications. Getting your uACR level down will help lower your risk for complications, even if you are not able to get your uACR level into the goal range.
Diagnosis
Urine albumin-creatinine ratio (uACR)
The primary way to diagnose albuminuria is through a urine test called the urine albumin-creatinine ratio (uACR). Your uACR results help describe the degree of albuminuria you may be experiencing, if any.
A lower number is better for this test, ideally lower than 30. A value of 30 or higher suggests you may be at a higher risk for complications. The higher your number, the higher your risk.
It is important to emphasize that this test often needs to be repeated one or more times to confirm the results. Decisions are rarely made based on the results of one test