Albumin
Albumin is the most abundant protein in your blood, making up about 60% of total plasma protein. Produced by the liver, this essential protein maintains fluid balance in your blood vessels, transports hormones and medications throughout your body, and serves as a key indicator of both liver function and nutritional status. Low levels signal important health issues — liver disease, kidney problems, malnutrition, or chronic inflammation — often before obvious symptoms appear.
Albumin is the most abundant protein in your blood, making up about 60% of total plasma protein. Produced by the liver, this essential protein maintains fluid balance in your blood vessels, transports hormones, vitamins, and medications throughout your body, and serves as a key indicator of both liver function and nutritional status.
Why does testing matter? Because low levels signal important health issues — liver disease, kidney problems, malnutrition, or chronic inflammation. This protein drops before obvious symptoms appear, making it valuable for early detection. It’s also a powerful predictor of health outcomes: low levels are associated with increased risk of complications in hospitalized patients and poorer outcomes in chronic disease.
This test is valuable for assessing liver function, evaluating nutritional status, monitoring chronic diseases, and understanding why you might have unexplained swelling (edema). Combined with other liver and kidney markers, it provides essential insight into your overall health.
Key Benefits of Testing
This blood test evaluates liver synthetic function — how well your liver produces proteins. Since this is the primary protein made by the liver, low levels can indicate liver damage or disease before other symptoms appear. It’s more sensitive to chronic liver problems than acute ones.
The test also assesses nutritional status. Inadequate protein intake or poor absorption leads to decreased production. In hospitalized or chronically ill patients, levels help identify malnutrition risk. Additionally, low values explain fluid retention — when this protein drops, fluid leaks from blood vessels into tissues, causing edema (swelling in legs, abdomen). Testing identifies this cause of unexplained swelling.
What Does This Test Measure?
The test measures the concentration of this protein in your blood serum. It’s produced exclusively by the liver at a rate of about 10-15 grams daily in healthy adults.
What This Protein Does
Maintains oncotic pressure: This is the primary function. The protein keeps fluid inside blood vessels by creating osmotic pressure. When levels drop, fluid leaks into tissues causing edema.
Transports substances: Carries hormones (thyroid, cortisol), fatty acids, bilirubin, calcium, and many medications through the bloodstream. Drug binding affects how medications work.
Antioxidant function: Acts as an antioxidant, helping neutralize harmful free radicals in the blood.
pH buffer: Helps maintain blood pH within normal range.
Production and Turnover
The liver produces this protein continuously. It has a half-life of about 20 days — meaning levels change slowly. This makes it a better marker of chronic conditions than acute changes. Sudden liver injury won’t immediately lower levels; chronic liver disease will.
Why Levels Drop
Levels decrease when: the liver can’t produce enough (liver disease), you’re not getting adequate protein (malnutrition), you’re losing protein (kidney disease, burns), or increased breakdown occurs (inflammation, infection). The pattern of other test results helps determine which cause applies.
Why This Test Matters
Assesses Liver Function
Since the liver produces this protein, low levels indicate impaired liver synthetic function. This occurs in cirrhosis, chronic hepatitis, and advanced liver disease. It’s often part of liver function panels to assess how well the liver is working — not just whether it’s damaged (which enzymes show), but whether it’s functioning adequately.
Evaluates Nutritional Status
This protein is a traditional marker of protein-calorie nutrition. Low levels suggest inadequate protein intake or absorption. In hospitalized patients, elderly, or those with chronic illness, testing helps identify malnutrition that might otherwise go unrecognized.
Explains Edema
When this protein drops significantly, fluid leaks from blood vessels into tissues — causing swelling in the legs, abdomen (ascites), or throughout the body. If you have unexplained edema, testing helps determine if low protein is the cause.
Predicts Health Outcomes
Low levels are associated with worse outcomes across many conditions — increased surgical complications, longer hospital stays, higher mortality in critical illness. This predictive value makes it important for risk assessment.
Monitors Chronic Disease
In chronic conditions like liver cirrhosis, nephrotic syndrome, or inflammatory diseases, serial testing tracks disease progression and response to treatment.
What Can Affect Your Levels?
Causes of Low Levels
Liver disease: Cirrhosis, chronic hepatitis, and liver failure reduce production. This is often the most concerning cause of low values.
Kidney disease (nephrotic syndrome): Damaged kidneys leak protein into urine, causing significant losses. Nephrotic syndrome is a major cause of very low levels.
Malnutrition: Inadequate protein intake or absorption reduces production. Common in elderly, chronically ill, or those with eating disorders.
Inflammation: Acute and chronic inflammation suppresses production. This protein is a “negative acute phase reactant” — it decreases during inflammatory states.
Burns and wounds: Protein is lost through damaged skin and diverted to wound healing.
GI protein loss: Protein-losing enteropathy (intestinal protein loss) from various GI conditions.
Overhydration: Dilution from excess IV fluids can artificially lower measured levels.
Causes of High Levels
Dehydration: The most common cause — concentration effect from fluid loss makes levels appear elevated.
True overproduction is rare. High values almost always reflect dehydration rather than excess protein.
Testing Considerations
No fasting typically required. Results should be interpreted with hydration status in mind. Recent acute illness can temporarily affect levels due to inflammation. For chronic disease monitoring, trends over time are more meaningful than single values.
When Should You Get Tested?
Liver Disease Evaluation
If liver disease is suspected or diagnosed, this test assesses synthetic function — how well the liver produces proteins. Combined with other liver tests, it provides comprehensive liver evaluation.
Unexplained Edema or Ascites
Swelling in the legs or fluid in the abdomen (ascites) can result from low protein levels. Testing helps determine if this is the cause and guides treatment.
Nutritional Assessment
In patients at risk for malnutrition — elderly, hospitalized, chronic illness, eating disorders, malabsorption conditions — this test helps evaluate protein nutritional status.
Kidney Disease Monitoring
In nephrotic syndrome (protein-losing kidney disease), monitoring helps track disease severity and response to treatment.
Pre-Surgical Evaluation
Low levels increase surgical risk. Testing before major surgery helps identify patients who may need nutritional optimization first.
Chronic Disease Monitoring
In liver cirrhosis, inflammatory conditions, or other chronic diseases, serial testing tracks progression and treatment response.
Understanding Your Results
Your lab provides reference ranges. General interpretation:
Low levels: Indicate reduced production, increased loss, or dilution. Requires evaluation for liver disease, kidney disease, malnutrition, or inflammation. Significantly low values can cause symptoms (edema).
Normal levels: Suggest adequate liver synthetic function and protein nutrition. However, mild disease may exist with normal levels.
High levels: Almost always indicate dehydration. Ensure adequate hydration and retest if needed.
Interpreting with Other Tests
Context from other tests helps identify the cause of low values:
Low + elevated liver enzymes + low platelets: Suggests liver disease
Low + protein in urine: Suggests nephrotic syndrome (kidney protein loss)
Low + elevated CRP/inflammation markers: Suggests inflammation-related decrease
Low + low prealbumin + weight loss: Suggests malnutrition
Slow Changes
Remember, this protein has a 20-day half-life. Levels change slowly, reflecting chronic rather than acute conditions. Sudden illness won’t immediately lower values; chronic conditions will.
What to Do About Low Levels
Address Underlying Cause
Treatment depends on why levels are low:
Liver disease: Treat underlying liver condition. Levels may improve with disease control but often remain low in cirrhosis.
Nephrotic syndrome: Treat kidney disease. Reducing protein loss improves levels.
Malnutrition: Improve protein intake. Oral protein supplementation or, in severe cases, enteral/parenteral nutrition.
Inflammation: Treat underlying inflammatory condition. Levels improve as inflammation resolves.
Manage Symptoms
If low levels cause edema, management includes sodium restriction, diuretics (to remove excess fluid), and addressing the underlying cause. Severe cases may require IV infusions temporarily.
Nutritional Support
For malnutrition-related deficiency, increase dietary protein: meat, fish, eggs, dairy, legumes. Protein supplements may help. Work with a dietitian for personalized guidance, especially in complex medical situations.
Monitoring
Serial testing tracks response to treatment. Given the 20-day half-life, allow adequate time between tests to see meaningful changes.
Related Health Conditions
Liver Disease
Cirrhosis: Advanced liver scarring impairs production. Low levels indicate advanced disease and poorer prognosis.
Chronic Hepatitis: Prolonged liver inflammation can eventually impair synthetic function.
Kidney Disease
Nephrotic Syndrome: Massive protein loss in urine leads to very low blood levels and severe edema.
Nutritional Conditions
Protein-Calorie Malnutrition: Inadequate nutrition reduces production. Common in hospitalized, elderly, and chronically ill patients.
Inflammatory Conditions
Chronic Inflammation: Inflammatory diseases suppress production as part of the acute phase response. This complicates interpretation in inflammatory conditions.
Edema and Ascites
Fluid Retention: Low levels cause fluid to leak from blood vessels, resulting in leg swelling or abdominal fluid accumulation.
Why Regular Testing Matters
In chronic conditions affecting the liver, kidneys, or nutritional status, regular testing tracks disease progression and treatment response. Declining levels may signal worsening disease before symptoms change. Improving levels indicate effective treatment.
For those at risk of malnutrition, periodic testing catches nutritional decline early — when intervention is easier and more effective than waiting for obvious signs.
Related Biomarkers Often Tested Together
Total Protein — Measures all blood proteins. Provides context for interpreting this specific protein.
ALT and AST — Liver enzymes showing liver cell damage. Combined with this protein, provides complete liver picture.
Bilirubin — Another marker of liver function, often tested alongside.
Creatinine and BUN — Kidney function markers. Help distinguish liver from kidney causes of low protein.
Prealbumin — Shorter half-life than this protein; responds faster to nutritional changes. Better for monitoring acute nutritional status.
Note: Information provided in this article is for educational purposes and doesn’t replace personalized medical advice.
Frequently Asked Questions
Low levels can indicate liver disease (reduced production), kidney disease (protein loss in urine), malnutrition (inadequate protein intake), or inflammation (suppressed production). The pattern of other test results helps determine the specific cause. Significantly low values cause edema due to fluid leaking from blood vessels.
Yes, but slowly. Severe protein malnutrition reduces levels over weeks to months. Short-term dietary changes won’t immediately affect results. For true malnutrition, improving protein intake gradually restores levels, but it takes time given the 20-day half-life.
During acute inflammation or infection, the liver shifts protein production toward inflammatory proteins (like C-reactive protein) and away from this protein. So levels decrease during inflammatory states — the opposite of “positive” acute phase reactants that increase.
Yes. Dehydration concentrates the blood, making levels appear higher than they truly are. This is the most common cause of elevated values. If results seem high, consider hydration status and retest when well-hydrated.
Both are liver-produced proteins used to assess nutrition and liver function. Prealbumin has a much shorter half-life (2-3 days vs. 20 days), so it responds faster to nutritional changes. For monitoring acute nutritional interventions, prealbumin is more useful. For assessing chronic status, this protein is valuable.
No. While liver disease is a major cause, kidney disease (nephrotic syndrome), malnutrition, and inflammation also cause low levels. The pattern of other tests helps distinguish between causes.
Depends on the clinical situation. For chronic liver or kidney disease: as directed by your provider, often every few months. For nutritional monitoring: periodically during treatment. For baseline health: as part of comprehensive metabolic panels when indicated.
References
Key Sources:
- Soeters PB, Wolfe RR, Shenkin A. Hypoalbuminemia: Pathogenesis and Clinical Significance. JPEN J Parenter Enteral Nutr. 2019;43(2):181-193.
- Nicholson JP, Wolmarans MR, Park GR. The role of albumin in critical illness. Br J Anaesth. 2000;85(4):599-610.
- Levitt DG, Levitt MD. Human serum albumin homeostasis: a new look at the roles of synthesis, catabolism, renal and gastrointestinal excretion. Int J Gen Med. 2016;9:229-255.
