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When conducting a biochemical blood test, the quantitative content of total protein is determined in it. It is represented by proteins that are present in plasma. There are several proteins in human blood, they all have differences in their structure, and also perform different functions. There are only five protein fractions in the blood, including: alpha-1 (α1), alpha-2 (α2), beta-1 (β1), beta-2 (β2) and gamma (γ). Beta-1 and beta-2 globulins are not measured separately, as this is of no diagnostic value.
Protein fractions of blood
An analysis that allows you to calculate the number of protein fractions in the blood is called a proteinogram. The doctor will be interested in the level of albumin in the blood (this protein dissolves in water) and globulins (these proteins do not dissolve in water, but break down when they enter an alkaline or saline environment).
High and low levels of proteins in the blood are not normal. Their imbalance characterizes certain disorders: immune, metabolic or metabolic.
With insufficient levels of albumin in the blood, liver dysfunction can be suspected, which is unable to provide the body with proteins. There may also be disturbances in the functioning of the kidneys or organs of the digestive system, as a result of which albumins will be excreted from the body too quickly.
If the level of protein in the blood is elevated, then this may be due to inflammatory processes. However, sometimes a similar situation is observed in quite healthy people.
To calculate which proteins in the body are deficient or overabundant, they are divided into fractions using the electrophoresis method. In this case, the analysis form will indicate the amount of total protein and fractions. Most often, doctors are interested in the values of albumin + globulins (albumin-globulin coefficient). Its norm values vary between 1,1-2,1.
Norms of protein fractions
Protein fraction | Norm g/l | Group ratio in percent |
Total protein | 65-85 |
|
Albumen | 35-55 | 54-65 |
Alpha-1 | 1,4-3,0 | 2-5 |
Alpha-2 | 5,6-9,1 | 7-13 |
Beta globulins | 5,4-9,1 | 8-15 |
Gamma globulins | 8,1-17,0 | 12-22 |
fibrinogen* | 2,0-4,0 |
|
Albumin-globulin ratio | 1,1-2,1 |
|
The amount of protein fractions will differ depending on the age of the person.
Age group | Albumin level in g/l | Alpha-1 in g/l | Alpha-2 in g/l | Beta in g/l | Gamma in g/l |
Newborn baby (first seven days of life) | 32,5-40,7 | 1,2-4,2 | 6,8-11,2 | 4,5-6,7 | 3,5-8,5 |
Child older than seven days and up to a year | 33,6-42,0 | 1,24-4,3 | 7,1-11,5 | 4,6-6,9 | 3,3-8,8 |
1-5 years | 33,6-43,0 | 2,0-4,6 | 7,0-13,0 | 4,8-8,5 | 5,2-10,2 |
5-8 years | 33,0-47,1 | 2,0-4,2 | 8,0-11,1 | 5,3-8,1 | 5,3-11,8 |
8-11 years | 40,6-45,6 | 2,2-3,9 | 7,5-10,3 | 4,9-7,1 | 6,0-12,2 |
11-21 year | 38,9-46,0 | 2,3-5,3 | 7,3-10,5 | 6,0-9,0 | 7,3-14,3 |
Over 21 years old | 40,2-50,6 | 2,1-3,5 | 5,1-8,5 | 6,0-9,4 | 8,1-13,0 |
It should be noted that the values of the norm may differ from the figures presented above, since each laboratory will have its own reference values.
Quantitative ratio of protein fractions
Most of all in the blood of albumin.
Depending on the proportion of the protein fraction present in the blood serum, they are distributed as follows (in descending order):
Albumins – 55-65%.
Gamma globulins – 12-22%.
Beta globulins – 8-12%.
Alpha-2 globulins – 6-12%.
Alpha-1 globulins – 2-4%.
Fibrinogen – about 2%.
Alpha globulins
Alpha globulins are charged in the same way as albumins, but they are larger in size. If inflammation develops in the human body, then their number increases dramatically. Therefore, alpha proteins are considered acute phase proteins due to their qualitative composition.
Alpha-1 globulins contain the following components:
Alpha-1 antitrypsin, which produces proteolytic enzymes.
Alpha-acid-glycoprotein, which helps to reduce the intensity of inflammation.
Prothrombin, which is responsible for blood clotting processes.
Alpha-1-lipoproteins, which transport lipids to tissue cells.
A thyroxine-binding protein that finds thyroxine (a protein produced by the thyroid gland) in the blood and transports it to the desired cells.
Transcortin is a globulin that is responsible for transporting cortisol.
Alpha-2 globulins are represented by the following components:
Alpha-2 macroglobulin, which is responsible for the body’s immune response. It begins to work actively when an inflammatory reaction develops in the body or when an infection enters it.
Glycoprotein is haptoglobulin, which is represented by a bundle with hemoglobin. With the destruction of red blood cells in the blood, the level of free haptoglobulin increases.
Ceruloplasmin is a metalloglycoprotein that is responsible for the transfer of copper from the blood to tissue cells. Also, this component of alpha-2-globulins is an antioxidant, and it also participates in the oxidation of serotonin, vitamin C, norepinephrine and other substances.
Apolipoprotein B, which carries molecules of “bad” cholesterol.
Alpha globulins are produced by hepatocytes. There are more of them in the body during an allergic reaction, against the background of inflammation, stress, and injury. Therefore, such proteins are called acute phase.
The level of alpha proteins in the blood can increase not only in acute inflammation, but also in subacute and even chronic disease.
Jumps in these protein fractions are characteristic of the following pathological conditions:
Pneumonia and other inflammatory reactions in the lung tissue.
Tuberculosis with exudate.
Penetration into the body of any infection.
Traumatic injuries of body tissues, burns and surgeries.
Acute inflammation of the joints, rheumatic fever.
Cancerous neoplasms of a malignant nature.
Sepsis.
Necrotic tissue damage.
Reception of male sex hormones.
Kidney diseases. In this case, alpha proteins will increase in the blood, and the remaining protein fractions will be deficient.
Low levels of alpha globulins are observed in respiratory failure and intravascular hemolysis.
Beta globulins
Beta globulins are represented by beta-1 and beta-2 protein fractions.
Together, they perform the following functions in the body:
Transferrin is a component of beta globulins responsible for transporting iron.
Hemopexin binds to hemoglobin and removes its excess from the body.
Beta-fractions of the protein component of the blood take part in the formation of the immunological reaction.
Beta-lipoproteins carry cholesterol and phospholipids, are directly involved in metabolic processes and the development of atherosclerosis.
If the level of beta fractions in the body rises, then this may indicate a disease that is accompanied by the accumulation of lipids in the body, as well as a pathology of the cardiovascular system.
Sometimes the amount of beta proteins increases in the body of a woman carrying a child.
In addition, the following diseases can lead to an increase in the level of beta proteins:
Malignant cancerous tumors.
progressive tuberculosis.
Hepatitis.
mechanical jaundice.
Iron-deficiency anemia.
Myelomas and monoclonal gammopathy.
Taking estrogen.
The level of beta-globulins decreases in inflammatory diseases, with infectious processes in the body, with diets with a limited intake of food in the body, with pathologies of the digestive tract.
Gamma globulin
Gamma globulins include acquired and natural antibodies that are responsible for the functioning of humoral immunity. Modern science knows 5 classes of gamma globulins, which are presented in the table.
Immunoglobulins | Percentage of globulins in blood serum | Description of gamma globulins |
lgG | About 75% | They have an antioxidant effect, fight viruses and gram-positive bacterial flora |
lgA | About 13% | Active against capsular bacteria, as well as against anti-insular antibodies that appear in the blood in diabetes mellitus |
lgM | About 12% | Active against gram-negative flora, take part in the suppression of serum sickness and syphilis |
lgE | 0,0 … | Appear in the blood in response to an allergic reaction |
lgD | Present in the blood of the fetus, in adults and children only traces of these gamma globulins can be detected | Do not have any clinical significance |
The amount of gamma globulins in the blood varies with the age of the person.
Person’s age | The level of immunoglobulins in the blood in g / l | ||
lgM | lgA | lgG | |
Children under 3 years old | 0,5-0,2 | 0,2-1,5 | 4,5-11,0 |
4-5 years old | 0,4-2,0 | 0,25-1,5 | 4,5-12,5 |
Children 6-8 years old | 0,5-2,0 | 0,3-2,0 | 6,3-13,0 |
Children 9-10 years old | 0,5-2,5 | 0,45-2,5 | 6,0-16,0 |
Adults and children over 10 years of age | 0,55-3,5 | 0,7-3,15 | 0,7-3,5 |
A high level of gamma globulins will be observed in the following pathological conditions:
Any inflammatory process that occurs in a chronic form with localization in the area of the joints, biliary or urinary system.
Infections that affect liver cells.
Poisoning, accompanied by lesions of the hepatic parenchyma.
Cirrhosis of the liver.
mechanical jaundice.
Pulmonary tuberculosis.
Infection of the body with parasites.
Autoimmune diseases.
Bronchial asthma.
Sarcoidosis of the lungs.
Myeloma, chronic lymphocytic leukemia, Waldenström’s macroglobulinemia.
The last stage of HIV.
A decrease in the level of gamma globulins is observed in the following pathologies:
AIDS.
Radiation sickness.
Splenectomy.
Treatment with cytostatics.
Lymphosarcoma, Hodgkin lymphoma.
Kidney damage with the development of nephrotic syndrome.
Infections and purulent inflammation, which has a protracted course.
Malnutrition in childhood.
Congenital forms of hypogammaglobulinemia and agammaglobulinemia.
During gestation, women may experience a decrease in the level of gamma globulins in the blood serum. Also, the fall in their numbers is facilitated by the passage of treatment with corticosteroids and the performance of plasmapheresis.
Analysis for blood globulins: what is the value?
Not always indicators of the level of total protein in the blood provide complete information about the existing disease. Therefore, doctors perform analysis to determine the various protein fractions.
This allows you to clarify the diagnosis and prescribe the correct treatment:
An increase in alpha globulins (alpha-1 and alpha-2) in the blood will indicate an acute inflammatory reaction. In this case, a viral infection can be suspected, which is concentrated in the lungs, bronchi, heart or kidneys. Also, their jump is observed during the development of a tumor in the body, or after receiving a serious injury. Surgical interventions lead to an increase in the level of alpha globulins.
Gamma globulins increase in the blood in diseases that have a chronic course. For example, with rheumatoid arthritis or cirrhosis of the liver.
A proteinogram is prescribed for acute inflammatory processes in the body, which are caused by various factors. The ratio of the level of protein fractions allows you to detect intestinal diseases, as well as depletion of the body. Also, this laboratory study makes it possible to detect latent infections, it is used to control ongoing therapy.