An albumin assay is a common blood test that measures the amount of albumin in your bloodstream. Albumin is a protein produced by the liver that performs several functions in the body. This test is often used as part of a routine health screening to evaluate liver and kidney function, as well as a person’s nutritional status.
What Is Albumin and Why Is It Important?
Albumin is the most abundant protein in blood plasma and is produced by the liver. One of its primary functions is to maintain oncotic pressure, which keeps fluid inside blood vessels. This prevents fluid from leaking into surrounding tissues and causing swelling.
Albumin also acts as a transport vehicle for substances like hormones, vitamins, calcium, and enzymes. It binds to these compounds and carries them through the bloodstream to their intended destinations. This transport function also affects how certain medications are distributed and used by the body.
Common Reasons for an Albumin Test
A healthcare provider may order an albumin test as part of a routine check-up to assess general health. It is a standard component of a comprehensive metabolic panel (CMP) or liver function tests (LFTs). These panels provide a snapshot of your metabolic health and organ performance.
The test is also used to investigate symptoms that suggest liver or kidney problems. These symptoms can include jaundice, swelling in the abdomen or legs, dark urine, or persistent fatigue. Because the liver produces albumin and the kidneys filter it, abnormal levels can indicate disease in these organs.
The assay is also used to evaluate nutritional status, as low albumin can suggest malnutrition or malabsorption from conditions like Crohn’s disease. In hospitals, the test helps monitor critically ill patients, those with extensive burns, or individuals recovering from surgery. This is because their nutritional needs and organ function can change rapidly.
Undergoing an Albumin Assay: What to Expect
Measuring albumin is done with a blood test, where a professional draws a sample from a vein in your arm. The process is quick, lasting less than five minutes. You might feel a slight sting from the needle and have minor, temporary bruising at the site afterward.
No special preparation is needed for an albumin test alone. However, it is often part of a larger panel that may require you to fast for several hours. Inform your healthcare provider of any medications you are taking, as drugs like anabolic steroids, insulin, and some hormones can influence the results.
Albumin can also be measured with a urine test to detect microalbuminuria, or small amounts of albumin in the urine. This test is useful for screening for early kidney damage, a common complication of diabetes. The results are often compared to urine creatinine levels for a more accurate assessment of kidney function.
Understanding Normal Albumin Levels and Variations
Albumin test results are reported in grams per deciliter (g/dL), with a normal range between 3.4 and 5.4 g/dL. This range can vary slightly between laboratories based on their measurement techniques. Your provider will interpret your results using the specific reference range from the lab that performed the test.
Slight fluctuations in albumin levels can occur that are not related to a significant medical condition. For instance, albumin levels can be lower during pregnancy.
What Low or High Albumin Levels Can Mean
Persistently low albumin levels, or hypoalbuminemia, can signal several health issues. Because the liver is the sole producer of albumin, liver diseases like cirrhosis or hepatitis can impair its ability to make the protein. This impairment leads to low levels in the blood.
Kidney disease is another cause of low albumin. Healthy kidneys prevent albumin from passing into the urine, but damaged kidneys can become leaky, allowing it to be lost from the body. Other causes of low albumin include:
- Malnutrition
- Severe infections or widespread inflammation
- Digestive diseases, such as Crohn’s disease, that interfere with protein absorption
- Kidney conditions, like nephrotic syndrome, that cause protein to leak into the urine
High albumin levels, or hyperalbuminemia, are much less common than low levels. This condition is most frequently a sign of dehydration, which concentrates albumin in the blood. In rare cases, high levels may be associated with receiving large amounts of intravenous albumin.