Albumin

Albumin is a water-soluble protein synthesized in the liver and found in the blood plasma, serving various functions including maintaining oncotic pressure and transporting hormones, fatty acids, and other substances.

Because of its many roles in human health, albumin serves as a crucial biomarker in medical diagnostics: its presence and concentration offer valuable insights into various physiological and pathological conditions within the body. 

Understanding albumin's role as a biomarker is essential for healthcare professionals in diagnosing and managing numerous diseases effectively.

Understanding Albumin: What is Albumin?

What is Albumin in a Blood Test? 

Albumin is a water-soluble protein, constituting about half of the total protein content in healthy human plasma (3.5 g/dL to 5 g/dL).  It is synthesized in the liver hepatocytes and swiftly enters the bloodstream. 

As the most abundant protein in the blood, albumin is a modulator of plasma oncotic pressure and a carrier for both endogenous and exogenous substances, including drugs. Serum albumin levels are utilized in clinical medicine as markers of an individual's nutritional status and liver function, offering insights into the body's ability to synthesize essential proteins and maintain overall homeostasis. 

Albumin is administered as a colloid fluid in patient fluid resuscitation, particularly in trauma scenarios or large-volume paracentesis procedures.

Functions of Albumin in the Body: What Does Albumin Do?  [2., 7.]

Albumin actively contributes to several essential functions in human health. 

Albumin modulates plasma oncotic pressure, which regulates the amount of fluid in the blood vessels.  Its role in oncotic pressure management ensures proper hydration and prevents fluid buildup in tissues. 

Albumin also acts as a general carrier molecule, transporting various substances such as metal cations, fatty acids, many hormones, bilirubin, metalloporphyrins, nitric oxide, aspirin, warfarin, ibuprofen, phenylbutazone, and others throughout the body. 

Albumin exhibits diverse redox properties, trapping reactive oxygen species (ROS) and demonstrating antioxidant capabilities. 

Moreover, albumin plays a role in copper transport and possesses both antioxidant and prooxidant activities, impacting redox reactions and signaling pathways. These redox-modulating properties of albumin have implications for various physiological processes and diseases, yet further research is needed to elucidate its specific effects on different tissues and its role in pathogenesis.

Moreover, it aids in buffering pH levels, assisting in maintaining the body's acid-base balance.

Glycated Albumin and Disease Risk  [2.]

Glycation is a non-enzymatic chemical reaction between sugars and proteins or lipids in the blood, resulting in the formation of advanced glycation end-products (AGEs) that can impact the structure and function of biomolecules and contribute to various health complications.

Glycated albumin, a product of non-enzymatic glycation of albumin molecules in the bloodstream, is a significant marker for predicting diabetes risk and systemic effects of advanced glycation end-products (AGEs). 

While initially synthesized as a non-glycosylated protein, albumin gradually undergoes glycation, with up to 40% of circulating proteins being glycated in diabetic individuals. This glycation alters albumin's structure and function, making it a target for immune responses, including autoantibody production. 

Measurement of glycated albumin levels offers diagnostic utility comparable to plasma glucose and HbA1c in diabetes monitoring. However, methods for detecting glycated albumin vary in complexity and accessibility. 

Glycated albumin not only serves as a marker of hyperglycemia but also exhibits pleiotropic effects on endothelial cells (ECs). It interacts with the endothelium through various receptors and influences vascular function and permeability. 

Glycated albumin induces the expression of procoagulant and inflammatory factors in ECs, contributing to endothelial dysfunction, atherosclerosis, and cardiovascular diseases. Moreover, it plays a role in the pathogenesis of diabetic complications such as neuropathy and nephropathy. 

Additionally, glycated albumin alters the behavior of blood cells, exacerbating endothelial damage and thrombogenicity. 

Factors Affecting Albumin Levels

Several factors can influence albumin levels in the blood, including hydration status, nutritional intake, liver function, and underlying medical conditions. 

Dehydration, malnutrition, liver disease, kidney disease, and inflammatory conditions are among the many factors that can either elevate or decrease albumin levels. 

Healthcare providers consider these factors when interpreting albumin test results to ensure accurate diagnosis and appropriate treatment planning.

Lab Testing for Albumin

Knowing an individual’s albumin status provides valuable insights into overall health status and aids in the detection and monitoring of various medical conditions.

Albumin Blood Test: Procedure and Purpose

The albumin blood test is a routine diagnostic procedure that measures albumin levels in plasma.  Testing involves drawing a blood sample from a vein.  Fasting is typically required.

Reference Range for Albumin Levels

It is important to consult individual labs for reference ranges used.  Common reference ranges for albumin are given as 3.5 to 5.5 g/dL.  [3., 6.]

Clinical Significance of High Albumin Levels: What Does High Albumin Mean?

Typically, elevated albumin levels are associated with dehydration.  Additional findings may include elevated hemoglobin and/or hematocrit.  [1.]

Clinical Significance of Low Albumin Levels: What Does Low Albumin Mean?  [1., 4., 5., 8.]

Several conditions can cause decreases in albumin levels.  Edema may or may not be present in these conditions.   

Liver disease: cirrhosis, hepatitis, liver failure, chronic alcoholism, and other liver conditions can impair albumin synthesis.

‍Overhydration: rapid overhydration can cause a temporary decrease in albumin concentration.

Malnutrition: inadequate dietary protein intake or malabsorption disorders can lead to low albumin levels.

Kidney disease: nephrotic syndrome, a condition where the kidneys leak protein into the urine, can decrease albumin levels.

Gastrointestinal disorders: conditions such as Crohn's disease, celiac disease, and inflammatory bowel disease can interfere with albumin absorption.

Protein-losing enteropathy: disorders affecting the gastrointestinal tract, such as intestinal infections or lymphatic obstruction, can cause protein loss, including albumin.

Severe burns: extensive burns can lead to fluid loss and decreased albumin levels.

Proteinuria: excessive protein loss through the urine, often associated with kidney disease or certain medications, can result in low albumin levels.

Acute infections or inflammation: conditions such as sepsis, burns, trauma, or chronic inflammatory diseases can cause a temporary decrease in albumin due to increased demand or redistribution.

Congestive heart failure: fluid overload and dilutional effects can lead to decreased albumin concentrations.

Excessive diuresis: overuse of diuretic medications can lead to increased excretion of albumin.

Medications: certain drugs can affect albumin synthesis or metabolism.

Genetic disorders: rare genetic conditions affecting albumin production or metabolism can lead to low levels.  Additionally, Wilson’s disease can cause low albumin levels.  

Chronic illnesses: long-term diseases such as cancer, HIV/AIDS, thyroid diseaese, and autoimmune disorders can contribute to low albumin due to increased metabolic demands or inflammation.

Pregnancy: Albumin levels may decrease during pregnancy due to physiological changes and increased demand for nutrients.

Biomarkers Related to Albumin

Understanding albumin's role as a biomarker often involves considering other related markers that provide complementary information about a patient's health status.

Total Protein

Total protein encompasses all proteins present in the blood, including albumin and globulins. Measuring total protein levels alongside albumin and globulin allows for a comprehensive assessment of protein status in the body. 

Abnormalities in total protein levels can indicate various medical conditions, such as liver or kidney disease, malnutrition, or inflammatory disorders, necessitating further evaluation and management.

Globulin

Globulins comprise a diverse group of proteins including antibodies and carrier proteins, among others. The globulin fraction can be further subdivided into specific types, such as alpha, beta, and gamma globulins, each with distinct functions. 

Assessing globulin levels along with albumin provides valuable information about immune function, liver health, and overall protein balance in the body. 

Abnormalities in globulin levels may indicate immune disorders, infections, or certain cancers, warranting further investigation and targeted interventions.

Maintaining Healthy Albumin Levels

Maintaining optimal albumin levels is essential for overall health and well-being. This section explores strategies to increase or decrease albumin levels as appropriate, depending on individual health needs and medical conditions.

To maintain optimal albumin levels, a multifaceted approach is often necessary. Firstly, treating the cause of low or high albumin levels is necessary and may warrant medical interventions.  

Additionally, dietary interventions and appropriate hydration play a crucial role. 

How to Raise Albumin Levels

Consuming a well-balanced diet rich in protein is recommended. Foods high in protein include lean meats, poultry, fish, eggs, dairy products, legumes, nuts, and seeds. Additionally, incorporating foods rich in essential amino acids, such as lysine and methionine, can support albumin synthesis in the body.

In some cases, medical treatments are necessary to increase albumin levels. Healthcare providers may prescribe albumin infusions or administer medications to address underlying medical conditions contributing to hypoalbuminemia, such as liver or kidney disease.

How to Lower Albumin Levels

Maintaining adequate hydration is important for supporting albumin blood concentration and maintaining blood volume. Encouraging patients to drink sufficient fluids, such as water, herbal teas, and electrolyte-rich beverages, can help prevent dehydration and support overall health.

Testing Options for Albumin Levels

Click here to compare testing options and order tests for albumin.