Total protein in the blood

The concentration of total protein in the blood serum depends mainly on the synthesis and breakdown of two main protein fractions - albumin and globulins. The physiological roles of blood proteins are numerous, the main ones are as follows:

• maintain colloid-oncotic pressure, maintaining blood volume, binding water and retaining it, preventing it from leaving the bloodstream;
• participate in blood clotting processes;
• maintain the constancy of blood pH, forming one of the blood's buffer systems;
• combining with a number of substances (cholesterol, bilirubin, etc.), as well as with drugs, they deliver them to tissues;

Reference values (norm) for the concentration of total protein in blood serum are 65-85 g/l.

• maintain normal levels of cations in the blood by forming non-dialyzable compounds with them (for example, 40-50% of serum calcium is bound to proteins; a significant portion of iron, copper, magnesium and other trace elements is also bound to proteins);
• play a vital role in immune processes;
• serve as a reserve of amino acids;
• perform a regulatory function (hormones, enzymes and other biologically active protein substances).

Causes of increase and decrease of total protein in the blood

The synthesis of blood plasma proteins occurs mainly in the cells of the liver and reticuloendothelial system. A reduced concentration of proteins in the blood is called hypoproteinemia, an increased concentration is called hyperproteinemia.

Hypoproteinemia occurs due to:

• insufficient protein intake (during prolonged fasting or during prolonged adherence to a protein-free diet);
• increased protein loss (in various kidney diseases, blood loss, burns, neoplasms, diabetes, ascites);
• disruption of protein formation in the body, with liver failure (hepatitis, cirrhosis, toxic damage), long-term treatment with glucocorticosteroids, impaired absorption (with enteritis, enterocolitis, pancreatitis);
• combinations of various of the factors listed above.

Hyperproteinemia often develops as a consequence of dehydration due to the loss of part of the intravascular fluid. This occurs with severe injuries, extensive burns, cholera. In acute infections, the concentration of total protein often increases due to dehydration and a simultaneous increase in the synthesis of acute phase proteins. In chronic infections, the content of total protein in the blood can increase as a result of the activation of immunological processes and increased formation of Ig. Hyperproteinemia occurs when paraproteins appear in the blood - pathological proteins produced in large quantities in myeloma, Waldenström's disease.

The total protein concentration can be affected by body position and physical activity. Vigorous physical work and changing body position from horizontal to vertical increases the protein content by 10%.

Determining the concentration of total protein allows us to assess the severity of protein metabolism disorders in a patient and prescribe adequate therapy.