What is albumin?

Albumin is the most abundant protein in the body. But what causes low albumin in the blood and what does this mean?

We look at the function of albumin and how doctors interpret levels of albumin.

- What is albumin?
- When is albumin measured?
- What does albumin do?
- What is a normal albumin level?
- What does a low albumin level mean?
- What does a high albumin level mean?
- How can I improve my albumin levels?
- What should I do if my albumin levels are abnormal?

What is albumin?

Albumin is a protein made in the liver. It is a marker of liver and kidney health and is the most abundant protein in the blood.

Albumin is included in many of our blood tests that include a liver profile, such as our Advanced Well Man Blood Test, Advanced Well Woman Blood Test, and Ultimate Performance Blood Test.

When is albumin measured?

Albumin is usually included as part of a liver screen along with other biomarkers such as alanine aminotransferase (ALT), alkaline phosphatase (ALP), bilirubin, and gamma GT (GGT).

Some hormones, like testosterone, bind to albumin and become less active than when they are free. Therefore, to calculate free testosterone levels, labs must first measure total testosterone levels, albumin, and other proteins, then use a mathematical formula to work out an estimate.

What does albumin do?

Albumin keeps fluids from leaking out of blood vessels and carries hormones, fatty acids, vitamins, and medicines throughout the body.

As albumin is made in the liver, its concentration in the blood is sensitive to liver damage. High levels may indicate dehydration, or low levels could point towards liver damage, kidney disease, or inflammation in the body.

After albumin is made in the liver, the majority is secreted directly into the bloodstream, where it has two main functions [1, 2]:

• Maintains oncotic pressure — Albumin draws water into the blood vessels. If levels are low, fluid can leak into the surrounding tissues.
• Transports substances — Albumin is a transport protein, meaning it can bind and transport many different substances—like nutrients, enzymes, medications, and hormones—around the body.

What is a normal albumin level?

The normal concentration of albumin in healthy adults is 35 to 50 g/L (3.5 to 5 g/dL) [1]. It is important to look at the reference range given when interpreting results as they vary between laboratories. If your levels are above or below this range, it may suggest an underlying health condition.

What does a low albumin level mean?

A low albumin level (hypoalbuminaemia) may be a sign of inflammation, advanced liver damage, or kidney disease.

Causes of low albumin levels include [3]:

• Severe liver disease – Albumin is made by the liver, therefore conditions like liver cirrhosis (advanced scarring) can cause levels to drop. Water and salt retention in liver disease make this effect more marked [2].
• Kidney disease – Healthy kidneys act as a sieve to prevent albumin and other proteins from being lost in the urine. The sieve-like component becomes damaged in conditions such as nephrotic syndrome and chronic kidney disease (CKD). Uncontrolled diabetes may also cause low albumin indirectly if the condition damages the kidneys.
• Inflammatory processes – Inflammation, both short-term and chronic, can lower albumin levels. This includes sepsis, burns, trauma, surgery, and chronic inflammatory conditions.
• Diseases of the gut – Conditions like Crohn’s and coeliac disease can cause proteins, including albumin, to be lost through the gut faster than it is made.
• Malnutrition – Low albumin can be suggestive of malnutrition, though in these cases, there are often other bodily processes, such as inflammation, contributing to the low albumin levels.
• Cancer – Albumin levels are often lower in people who have cancer, especially in more advanced stages. The reason for this is not entirely clear but is likely multifactorial [4].
• Pregnancy — Concentrations of albumin naturally lower during the second and third trimesters of pregnancy due to an increase in plasma volume.

Low levels of albumin can cause several complications, including fluid leaking into different areas of the body. However, an albumin level just outside the normal range is unlikely to cause symptoms.

Complications of low albumin [3]:

• Swelling
• Ascites (fluid accumulation in the belly)
• Pleural effusion (fluid accumulation around the lungs)

In practice, albumin levels are useful as a prognostic indicator. Among hospitalised patients, lower serum albumin levels correlate with an increased risk of morbidity and mortality [5].

What does a high albumin level mean?

Higher than normal levels may be due to severe hydration (of which there are many causes) or may be an erroneous result due to a tourniquet being applied for too long during the blood draw.

Causes of high albumin include:

• Falsely elevated result due to prolonged tourniquet application
• Severe dehydration, for example, due to burns or severe diarrhoea
• Certain medications such as steroids and insulin

How can I improve my albumin levels?

An abnormal albumin result is best corrected by treating the underlying cause. Making sure you eat a well-balanced, nutritious diet, rich in protein is also important.

Although albumin supplements exist, they are unlikely to offer any benefit for people with slightly lowered albumin levels. When albumin supplementation is needed in hospitalised patients, albumin is often given as a solution directly into the bloodstream.

For some of the more severe conditions that cause low albumin, there is no cure. But some treatments can prevent disease progression or flare-ups. Sometimes, medications can counter the complications of low albumin. For example, diuretics (water tablets) can help the body get rid of excess fluid build-up.

What should I do if my albumin levels are abnormal?

If your albumin levels are abnormal, your doctor can advise you on any further additional tests you might need.

If you have received an abnormal result as part of a Medichecks blood test, we will always inform you if you should seek medical attention.

Relevant blood tests

Liver blood test — This simple finger-prick blood test includes important liver enzymes and proteins including albumin to give you an idea of how your liver is functioning.

Advanced Well Man Blood Test or Advanced Well Woman Blood Test— Our bestselling blood tests include not only a liver screen but a huge range of additional biomarkers to give you a much broader picture of your health.

References

1. Raoufinia, R., Mota, A., Keyhanvar, N., Safari, F., Shamekhi, S., & Abdolalizadeh, J. (2016). Overview of Albumin and Its Purification Methods. Advanced pharmaceutical bulletin, 6(4), 495–507. https://doi.org/10.15171/apb.2016.063
2. Moman RN, Gupta N, Varacallo M. Physiology, Albumin. [Updated 2021 Aug 9]. Treasure Island (FL): StatPearls Publishing; 2021 Jan. Available from: https://www.ncbi.nlm.nih.gov/books/NBK459198/?report=classic
3. Gounden V, Vashisht R, Jialal I. Hypoalbuminemia. [Updated 2021 Sep 28]. Treasure Island (FL): StatPearls Publishing; 2021 Jan. Available from: https://www.ncbi.nlm.nih.gov/books/NBK526080/
4. Nazha, B., Moussaly, E., Zaarour, M., Weerasinghe, C., & Azab, B. (2015). Hypoalbuminemia in colorectal cancer prognosis: Nutritional marker or inflammatory surrogate?. World journal of gastrointestinal surgery, 7(12), 370–377. https://doi.org/10.4240/wjgs.v7.i12.370
5. Kung, S. P., Tang, G. J., Wu, C. W., & Lui, W. Y. (1999). Serum albumin concentration as a prognostic indicator for acute surgical patients. Zhonghua yi xue za zhi = Chinese medical journal; Free China ed, 62(2), 61–67.