SERUM
PROTEINS
Proteins
are the most abundant compounds in your serum (the rest of your blood when you remove
all the cells). Amino acids are the building blocks of all proteins. In turn
proteins are the building blocks of all cells and body tissues. They are the
basic components of enzymes, many hormones, antibodies and clotting agents.
Proteins act as transport substances for hormones, vitamins, minerals, lipids
and other materials. In addition, proteins help balance the osmotic pressure of
the blood and tissue. Osmotic pressure is part of what keeps water inside a
particular compartment of your body. Proteins play a major role in maintaining
the delicate acid-alkaline balance of your blood. Finally, serum proteins serve
as a reserve source of energy for your tissues and muscle when you are not
ingesting an adequate amount.
The
major measured serum proteins are divided into two groups, albumin and
globulins. There are four major types of globulins, each with specific
properties and actions. A typical blood panel will provide four different
measurements - the total protein, albumin, globulins, and the albumin globulin
ratio.
Total
Protein
Because
the total protein represents the sum of albumin and globulins, it is more
important to know which protein fraction is high or low than what is the total
protein. Ideally, the total protein will be approximately 7.5 g/dl.
Optimal Range: 7.2-8.0 g/100ml
Total protein may be elevated
due to:
- Chronic infection (including tuberculosis)
- Adrenal cortical hypofunction
- Liver dysfunction
- Collagen Vascular Disease (Rheumatoid Arthritis,
Systemic Lupus, Scleroderma)
- Hypersensitivity States
- Sarcoidosis
- Dehydration (diabetic acidosis, chronic diarrhea,
etc.)
- Respiratory distress
- Hemolysis
- Cryoglobulinemia
- Alcoholism
- Leukemia
Total protein may be decreased
due to:
- Malnutrition and malabsorption (insufficient intake
and/or digestion of proteins)
- Liver disease (insufficient production of proteins)
- Diarrhea (loss of protein through the GI tract)
- Severe burns (loss of protein through the skin)
- Hormone Imbalances that favor breakdown of tissue
- Loss through the urine in severe kidney disease (proteinuria)
- Low albumin (see "albumin")
- Low globulins (see "globulins")
- Pregnancy (dilution of protein due to extra fluid
held in the vascular system)
Albumin
Albumin
is synthesized by the liver using dietary protein. Its presence in the plasma
creates an osmotic force that maintains fluid volume within the vascular space.
A very strong predictor of health; low albumin is a sign of poor health and a
predictor of a bad outcome.
Optimal Range: 4.5-5.0 g/100ml
Albumin levels may be elevated
in:
- Dehydration - actual
- Congestive heart failure
- Poor protein utilization
- Glucocorticoid excess (can result from taking
medications with cortisone effect, the adrenal gland overproducing
cortisol, or a tumor that produces extra cortisol like compounds)
- Congenital
Albumin levels may be decreased
in:
- Dehydration
- Hypothyroidism
- Chronic debilitating diseases (ex: RA)
- Malnutrition - Protein deficiency
- Dilution by excess H2O (drinking too much water,
which is termed “polydipsia,” or excess administration of IV fluids)
- Kidney losses (Nephrotic Syndrome)
- Protein losing-enteropathy (protein is lost from the
gastrointestinal tract during diarrhea)
- Skin losses (burns, exfoliative dermatitis)
- Liver dysfunction (the body is not synthesizing
enough albumin and indicates very poor liver function)
- Insufficient anabolic hormones such as Growth
Hormone, DHEA, testosterone, etc.
GLOBULINS,
Total serum
Globulins
are proteins that include gamma globulins (antibodies) and a variety of enzymes
and carrier/transport proteins. The specific profile of the globulins is
determined by protein electrophoresis (SPEP), which separates the proteins
according to size and charge. There are four major groups that can be identified:
gamma globulins, beta globulins, alpha-2 globulins, and alpha-1 globulins. Once
the abnormal group has been identified, further studies can determine the
specific protein excess or deficit. Since the gamma fraction usually makes up
the largest portion of the globulins, antibody deficiency should always come to
mind when the globulin level is low. Antibodies are produced by mature B
lymphocytes called plasma cells, while most of the other proteins in the alpha
and beta fractions are made in the liver.
Optimal Range: 2.3-2.8 g/dL
Optimal Range (Alpha
Globulin): 0.2-0.3 g/L
Optimal Range (Beta Globulin):
0.7-1.0 g/L
The globulin level may be elevated
in:
- Chronic infections (parasites, some cases of viral
and bacterial infection)
- Liver disease (biliary cirrhosis, obstructive
jaundice)
- Carcinoid syndrome
- Rheumatoid arthritis
- Ulcerative colitis
- Multiple myelomas, leukemias, Waldenstrom's
macroglobulinemia
- Autoimmunity (Systemic lupus, collagen diseases
- Kidney dysfunction (Nephrosis)
The serum globulin level may
be decreased in:
- Nephrosis (A Condition in which the kidney does not
filter the protein from the blood and it leaks into the urine)
- Alpha-1 Antitrypsin Deficiency (Emphysema)
- Acute hemolytic anemia
- Liver dysfunction
- Hypogammaglobulinemia/Agammaglobulinemia
A/G
(ALBUMIN/GLOBULIN) RATIO
The
liver can function adequately on 20% of liver tissue, thus early diagnosis by
lab methods is difficult. A reversed A/G Ratio may be a helpful indicator. With
severe liver cell damage, the prolonged prothrombin time will not change with
ingestion of Vitamin K. The proper albumin to globulin ratio is 2:1. When
<1.7, there is may be a need for increasing stomach acidity. When >3.5
there may be a need for stomach acidity and pepsin.
Optimal Range: 1.7-2.2
The AG ratio may be elevated
in:
- Hypothyroidism
- High protein/high carbohydrate diet with poor
nitrogen retention
- Hypogammaglobulinemia (low globulin)
- Glucocorticoid excess (can be from taking medications
with cortisone effect, the adrenal gland overproducing cortisol, or a
tumor that produces extra cortisol like compounds, low globulin)
The AG ratio may be decreased
in: