In a healthy individual, which protein fraction has the greatest concentration in serum?

In a healthy individual, which protein fraction has the greatest concentration in serum?

• A. Alpha1-globulin
• B. Beta-globulin
• C. Gamma-globulin
• D. Albumin

Answer: (D)

Albumin is the most abundant protein in normal serum, which is why it has the greatest concentration in healthy individuals. It’s produced mainly by the liver in large amounts and makes up about 60% of total serum protein, roughly 3.5–5 g/dL. This high level gives albumin a central role in maintaining oncotic (colloid osmotic) pressure, helping keep fluid inside blood vessels, and it also serves as a major carrier for many substances, including medications, fatty acids, and bilirubin. The other protein fractions—alpha-1, alpha-2, beta, and gamma globulins—are present in smaller amounts. Gamma globulins are immunoglobulins involved in immune defense and comprise only a portion of total serum protein, not approaching the level of albumin. So, in a healthy person, the dominant concentration in serum is albumin.

Albumin is the most abundant protein in normal serum, which is why it has the greatest concentration in healthy individuals. It’s produced mainly by the liver in large amounts and makes up about 60% of total serum protein, roughly 3.5–5 g/dL. This high level gives albumin a central role in maintaining oncotic (colloid osmotic) pressure, helping keep fluid inside blood vessels, and it also serves as a major carrier for many substances, including medications, fatty acids, and bilirubin.

The other protein fractions—alpha-1, alpha-2, beta, and gamma globulins—are present in smaller amounts. Gamma globulins are immunoglobulins involved in immune defense and comprise only a portion of total serum protein, not approaching the level of albumin. So, in a healthy person, the dominant concentration in serum is albumin.