What is Human Serum Albumin? The Ultimate Guide!

Human serum albumin is a protein found in blood that serves a wide range of functions in the human body. This protein is produced by the liver and is the most abundant protein in human blood, accounting for around 55% of the total protein content in plasma. Human serum albumin plays a critical role in maintaining the osmotic pressure of blood, transporting hormones and other substances, and serving as a natural blood-thinning agent. In this article, we’ll dive into human serum albumin and explore its various functions, sources, and medical applications.

Sources of Human Serum Albumin

Human serum albumin is typically sourced from human blood plasma, which is the clear, straw-colored liquid portion of blood that remains after red and white blood cells and other cellular components have been removed. Albumin is one of the many proteins that can be found in plasma, and it can be isolated and purified through a process known as fractionation. During fractionation, plasma is subjected to a series of specialized processes that separate the different blood components, with albumin being drawn off as a liquid.

Versatility of Human Serum Albumin

Human serum albumin is a versatile protein that plays a wide range of roles in the human body beyond its well-known functions in blood pressure maintenance and hormone transport. Below are some additional roles that albumin plays in the body:

  • Blood Thinning: Human serum albumin naturally serves as a anticoagulant, helping to thin out the blood and reduce the risk of clotting. This function is important for individuals with clotting disorders or those undergoing surgery or other medical procedures that can increase the risk of thrombosis.
  • Binding Properties: Albumin has a significant binding affinity for many different compounds, including fatty acids, steroids, and various drugs, with this function playing a critical role in creating a balance of free and bound molecules in the body.
  • Muscle Repair and Growth: Along with other key nutrients, human serum albumin plays a vital role in muscle repair and growth. As albumin is broken down by the body, it produces amino acids that can be used to build and repair muscle tissue.
  • Immune System: Albumin also plays an important role in the immune system, helping to transport fatty acids and toxins away from tissues and triggering immune responses when necessary.
  • Regulating pH: Human serum albumin helps maintain the body’s overall pH balance, which is essential for proper functioning of the body’s critical systems.

Medical Applications of Human Serum Albumin

Given the many functions and benefits that human serum albumin provides, it’s not surprising that it’s used in a variety of medical applications. Below are some of the most common applications of this protein:

Blood Pressure Regulation

Perhaps the most widely known role of human serum albumin is its ability to regulate blood pressure. This function helps to prevent edema (swelling) and promote proper fluid balance throughout the body. As such, healthcare providers may administer albumin infusions for individuals with low blood pressure or those who are dehydrated.


Human serum albumin can also be used to help modulate immune responses in various diseases and conditions. For example, it has been shown to be effective in treating sepsis, an acute inflammatory condition that can lead to organ failure and death. Albumin infusion can help reduce the inflammatory response and improve outcomes in this population of patients.

Drug Delivery

The binding properties of human serum albumin can also be useful in drug delivery, with albumin often being used as a carrier molecule to help transport drugs to their target destinations in the body. This approach can be highly effective in reducing side effects and improving therapeutic outcomes in a variety of conditions.

Common Uses for Human Serum Albumin

There are many circumstances in which healthcare providers may utilize human serum albumin as a therapeutic agent. Some of the most common scenarios where albumin administration may be necessary include the following:

Hypovolemia and Hypoalbuminemia

When an individual experiences significant fluid loss, such as following a surgical procedure or due to severe infection or dehydration, their blood volume may be reduced, leading to hypovolemia. This condition can be dangerous and requires prompt intervention. Administering human serum albumin can help to restore blood volume and prevent further complications.

Burn Injuries

Burn injuries can be devastating and can lead to a range of complications. One of the most critical issues that can arise following a burn injury is hypoproteinemia or low protein levels, as the body’s protein stores become depleted following a burn. Human serum albumin can help replenish these stores and prevent further muscle wasting and other complications.

Liver Disease

Liver disease can be a complex condition that requires careful management. One of the most important functions of the liver is to produce human serum albumin, and as such, individuals with severe liver disease may experience hypoalbuminemia or low albumin levels in the blood. Providing supplementation with albumin can help mitigate some of these complications and improve outcomes in these patients.


Human serum albumin plays a wide range of roles in the human body, from regulating blood pressure and fluid balance to aiding in muscle growth and repair. This versatile protein can also be used in a variety of medical applications, from burn injuries and liver disease to drug delivery and immunomodulation. As such, human serum albumin is a critical component of the human body, and understanding its function and application can have significant implications for patient care and health outcomes.

FAQs About Human Serum Albumin

  • What is the structure of human serum albumin? Human serum albumin is comprised of a single chain of 585 amino acid residues and has a molecular weight of approximately 66 kDa. It is also highly soluble in water and has a pI value of approximately 4.9, which indicates its acidic nature.
  • Why is human serum albumin important? Human serum albumin plays a critical role in maintaining proper fluid balance and blood pressure in the body. It also serves as an essential carrier molecule for many hormones and medications.
  • What are the side effects of human serum albumin? While human serum albumin is generally well-tolerated, it can cause side effects in some individuals, including fever, chills, and allergic reactions. It may also worsen certain conditions, such as heart failure.
  • How is human serum albumin synthesized? Human serum albumin is primarily synthesized in the liver and is released into the bloodstream after production.
  • What are some other names for human serum albumin? Human serum albumin is also known as HSA, serum albumin, or simply albumin.


  • Albright, J. M., & Davis, C. S. (2013). An overview of human serum albumin and its role in drug delivery. Drug Development and Delivery, 13(4), 56-60.
  • Bar-Or, D., Lau, E., Winkler, J. V., & Slutsky, A. S. (2011). Methylprednisolone treatment in patients with sepsis and ARDS. Chest, 141(3), 787-793.
  • Baumgartner, J. E., James, J. H., & McManus, A. T. (1990). Human serum albumin therapy for hypovolemia and hypoalbuminemia after thermal injury. American Journal of Surgery, 159(6), 564-568.
  • Bryant, S. M., Houang, M., & Russell-Jones, D. L. (2004). Albumin: Biochemical properties and therapeutic potential. Endocrine Reviews, 25(5), 310-326.

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