Serum Albumin
Albumin is the most abundant protein in blood plasma, produced by the liver. It performs several vital functions: maintaining fluid balance (oncotic pressure) to prevent edema, transporting hormones, drugs, and fatty acids, and serving as a nutritional marker. Low albumin is a red flag for liver disease, kidney disease, or malnutrition.
Reference Ranges
Male
3.5 – 5.5
g/dL
Female
3.5 – 5.5
g/dL
Child
3.5 – 5.5
g/dL
Ages 1–18
Reference ranges may vary by laboratory. Always compare with the range printed on your lab report.
What Low Levels Mean
Low albumin (hypoalbuminemia) causes fluid to leak from blood vessels into tissues, causing swelling (edema) — especially in the legs and abdomen (ascites). Causes include liver disease (cirrhosis), nephrotic syndrome (kidney protein loss), malnutrition, chronic inflammation, and severe burns.
What High Levels Mean
High albumin is almost always due to dehydration (concentrated blood). True overproduction of albumin is extremely rare. If albumin is high with other concentrated values (hemoglobin, hematocrit), dehydration is the likely explanation.
Frequently Asked Questions
Why is albumin important in liver disease?
The liver produces albumin, so low albumin is a key marker of liver damage. In cirrhosis, the liver can no longer produce enough albumin, leading to fluid retention, ascites, and edema. Albumin level helps determine the severity of liver disease (Child-Pugh score).
Can low albumin be caused by diet?
Yes. Severe protein malnutrition (kwashiorkor) causes very low albumin. However, in developed settings, low albumin more often reflects chronic disease or inflammation rather than dietary deficiency. The body prioritizes albumin production — it drops only in significant illness or prolonged malnutrition.
What is the albumin/globulin ratio?
The A/G ratio compares albumin to globulin (other blood proteins). A normal ratio is 1.1–2.5. A low ratio may indicate liver disease, autoimmune conditions, or chronic infection. A high ratio is less common and usually not clinically significant.
This information is for educational purposes only and should not replace professional medical advice. Always consult your doctor for interpretation of your test results.
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