Albumin
The most abundant blood protein, made by the liver, which maintains fluid balance and transports substances.
| Typical reference range | 3.6–5.1 g/dL |
| Commonly cited optimal range | above 4.2 g/dL |
Ranges vary by laboratory, method, age and sex: always use the range printed on your own report. Why labs differ.
What it measures
Albumin keeps fluid inside blood vessels (oncotic pressure) and carries hormones, calcium, bilirubin, fatty acids and drugs. It is made exclusively by the liver and has a half-life of about 3 weeks.
Why it matters
Albumin reflects liver synthetic function, nutrition and inflammation. Lower albumin, even within the normal range, is associated with higher mortality, while it is also needed to interpret total calcium.
What a high result can mean
High albumin is almost always due to dehydration or prolonged tourniquet use.
What a low result can mean
Low albumin occurs with liver disease, inflammation or infection (it is a negative acute-phase protein), kidney loss (nephrotic syndrome), protein-losing gut conditions, malnutrition and overhydration.
What affects the result
Hydration status strongly affects it. Inflammation lowers it independent of nutrition. Interpret with total protein, globulin, liver enzymes and urine albumin.
Units and conversion
Usually reported in g/dL.
- From g/L: multiply by 0.1 to get g/dL
Also called on lab reports
Albumin, Serum, Serum Albumin, ALB
Related tests: Blood Proteins
This page is educational and does not replace advice from a healthcare professional.