What is the main component of total protein measured in serum?

The main component of total protein measured in serum is albumin. Albumin plays a crucial role in maintaining oncotic pressure in the bloodstream, which helps to regulate the distribution of fluids between blood vessels and tissues. It is also involved in transporting various substances, including hormones, vitamins, and drugs, throughout the body.

Albumin constitutes a significant portion of the total protein concentration in serum, typically accounting for about 60% of total plasma proteins. Its concentration can provide valuable insights into a patient's nutritional status, liver function, and overall health.

Globulin is another protein fraction that is part of total serum protein, but albumin remains the most abundant and is therefore the primary focus when measuring total protein levels. Fibrinogen, while important for blood coagulation, is typically measured separately and is not considered a major contributor to the total protein content in serum. Transferrin, responsible for iron transport, is also present in smaller amounts compared to albumin and does not comprise the bulk of serum protein. Thus, albumin is correctly identified as the principal component of total protein in serum.