Blood serum contains ample proteins which are building blocks of body tissues and cells. Proteins provide energy to your tissues and muscles when you are not ingesting an adequate amount. Albumin and globulin are the two major types of proteins present in blood serum. Levels of albumin and globulin, levels of total proteins (sum of albumin and globulin) and the 'albumin/globulin ratio', are measured and taken into consideration while measuring serum proteins.
Globulins include sixty different proteins, such as, gamma globulins (antibodies) and glycoproteins (protein-carbohydrate compounds), clotting factors and carrier/transport proteins (lipoproteins). Globulins help fight infection, enhance the process of blood clotting and serve as carrier proteins for hormones. Protein electrophoresis (SPEP) helps separate different proteins according to the size and charge, and helps determine the specific profile of globulins.
The four major groups of globulin are gamma, beta, alpha-2 and alpha-1 globulins. To determine the excess or deficit levels of globulin, the abnormal group has to be detected. The gamma globulins form the largest portion of the globulins, therefore, low globulin levels straightaway indicate antibody deficiency.
Mature B lymphocytes known as plasma cells manufacture antibodies, while liver produces most of the other proteins in the alpha and beta fractions. The test known as 'serum globulin electrophoresis' helps measure the amount of globulin in blood.
What Do High Globulin Levels Indicate
- Chronic inflammatory diseases (ex: TB, Syphilis)
- Bone marrow disorders like multiple myeloma
- Waldenstrom's macroglobulinemia
- Autoimmunity (Systemic lupus, collagen diseases)
- Rheumatoid arthritis
- Liver disease (biliary cirrhosis, obstructive jaundice)
- Carcinoid syndrome
- Ulcerative colitis
- Kidney disease (Nephrosis)
- Chronic infections (parasites, some cases of viral and bacterial infection like viral hepatitis or HIV)
What Do Low Globulin Levels Indicate
- Hepatic dysfunction
- Celiac disease
- Proteins are not digested or absorbed properly
- Inflammatory bowel disease (IBD)
- Various neoplasms
- Acute hemolytic anemia
- Renal disease (A condition in which the kidneys do not filter the protein from the blood and it leaks into the urine).
Normal Levels of Blood Serum Proteins
- Total proteins 6.4 to 8.3 g/dL
- Albumin 3.5 to 5.0 g/dL
- Alpha-1 globulin: 0.1 to 0.3 g/dL
- Alpha-2 globulin: 0.6 to 1.0 g/dL
- Beta globulin: 0.7 to 1.2 g/dL
- Gamma globulin: 0.7 to 1.6 g/dL
- The proper albumin to globulin ratio (A/G) is 2:1.
- Optimal A/G Range: 1.7 - 2.2
The AG ratio may be seen elevated in:
- High protein/high carbohydrate diet with poor nitrogen retention
- Hypogammaglobulinemia (low globulin), decreased production of immunoglobulins (as may be seen in some genetic disorders and in certain types of leukemia)
- Glucocorticoid excess (due to some medications with cortisone effect, the adrenal gland overproducing cortisol, or a tumor that produces extra cortisol like compounds, low globulin)
Drugs like anabolic steroids, androgens (male hormones), growth hormone, insulin and progesterone may lead to increased protein levels. Drugs like estrogen, drugs that leave a toxic effect on the liver and oral contraceptives may cause decreased protein levels. Proteins help maintain the osmotic pressure (that determines the movement of water between the bloodstream and tissues) in the body.
Both serum albumin and serum globulin are measures of nutrition. The protein test is used to monitor the course of disease in certain cancers, to detect intestinal and kidney protein-wasting states, to diagnose immune disorders, liver dysfunction, kidney dysfunction, to find the cause of edema and impaired nutrition.
To measure the amounts and types of proteins in blood, protein component tests are recommended. The serum (blood) protein components test measures total protein along with its albumin and globulin components, which make up for most of the protein within the body. Globulin levels and albumin levels are usually checked to evaluate liver function. Any noticeable difference in the levels of globulin needs prompt medical attention and proper treatment.