Albumin
Primary plasma protein for protein synthesis, liver function, and nutritional status
Also known as
Definition
Albumin is the most abundant plasma protein (approximately 55–60% of total proteins) and is produced exclusively in the liver. It performs central transport functions (fatty acids, hormones, medications, bilirubin, calcium), regulates colloid osmotic pressure, and is an important indicator of liver function, nutritional status, and protein deficiency. Albumin is a negative acute-phase reactant — it falls during inflammation.
| Parameter | Value |
|---|---|
| Unit | g/l |
| Reference Range | 35–52 g/l |
| Optimal Range (lab2go) | 42–50 g/l (lab2go Optimum Zone — values < 40 g/l increase mortality risk; > 50 g/l seen in dehydration) |
↓ What a low value means
Hypoalbuminemia (< 35 g/l) can indicate liver disease (reduced synthesis — important functional parameter in cirrhosis), malnutrition/protein deficiency, nephrotic syndrome (renal loss), chronic inflammation (negative acute-phase reactant), heart failure, or burns. Clinical consequence: edema (reduced oncotic pressure), impaired drug binding.
↑ What a high value means
Elevated albumin (> 52 g/l) is usually a sign of dehydration (concentration effect). Rarely: congenital bisalbuminemia. In dehydration: albumin normalizes rapidly after rehydration.
✓ How to optimize this marker
Ensure adequate protein intake (1.2–1.6 g/kg/day); high-calorie protein shakes for malnutrition or cachexia. Treat the underlying condition (liver, kidney, inflammation). Albumin infusion is only used clinically for ascites or shock. Exercise and muscle maintenance improve albumin synthesis long-term.
When to test
Routinely in liver function panels; nutritional screening (MUST score uses albumin); for edema, ascites, liver disease, kidney disease (nephrotic syndrome), chronic inflammation, and bariatric follow-up. Albumin as a long-term malnutrition marker (half-life ~20 days; prealbumin ~2 days is more sensitive for short-term changes).
Frequently asked questions
Why is albumin often low in chronic disease? +
In chronic inflammation, the body releases IL-6 and other cytokines. These signal the liver to reduce albumin production in favor of acute-phase proteins like CRP and fibrinogen. Low albumin in inflammation primarily reflects the inflammatory state, not protein deficiency.
How long does it take for albumin to respond to improved nutrition? +
Albumin has a half-life of approximately 20 days — it responds slowly to nutritional improvement. Prealbumin (transthyretin, half-life ~2 days) and retinol-binding protein (half-life ~12 h) are more sensitive markers for short-term nutritional improvements. Albumin remains relevant for long-term assessment.
Why must albumin be considered when interpreting calcium? +
About 40% of blood calcium is bound to albumin. With low albumin, total calcium appears falsely low even though active ionized calcium is normal. Formula: corrected calcium = measured calcium + 0.02 × (40 − albumin g/l). Always measure ionized calcium when albumin is abnormal.
Is albumin a marker of liver function or nutritional status? +
Both — depending on context. In liver disease (cirrhosis): albumin is a synthesis parameter and part of the Child-Pugh score for severity. In other conditions: albumin primarily reflects nutritional status and degree of inflammation. Always interpret in the full clinical context alongside other lab values.
Sources
Last Reviewed: May 28, 2026 · sina
This information is for orientation only and does not replace medical advice. Reference ranges can vary by laboratory, method and country.