Download Serum proteins

Serum proteins
Normal values
Total serum protein
• Total protein: 5.5–9.0 grams per deciliter
(g/dL)
• Albumin:3.5–5.5 g/dL
• Globulin:2.0–3.5 g/dL
• Albumin/globulin ratio:
Greater than 1.0
ALBUMIN
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Is the most abundant protein produced in the liver
Constitutes about half of the blood serum protein it is soluble and
monomeric
• Transports hormone , fatty acid
• It has half life of approximately 20 day
• The gene for albumin is located on chromosome 4
And mutation in this gene result in anomalous protein
• A low molecular weight protein (M.Wt= 65,000 Dalton)
• It prevent leaking the blood from the capillary
Function
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Maintains oncotic pressure
Transports thyroid hormones
Transports other hormones, in particular, that are fatsoluble
• Transports fatty acids ("free" fatty acids) to the liver and
to myocytes for utilization of energy
• Transports unconjugated bilirubin
• Transports many drugs; serum albumin levels can affect
the half-life of drugs
• Competitively binds calcium ions (Ca2+)
• Buffers pH
• Prevents photodegradation of folic acid
Pathology
Low blood albumin levels (hypoalbuminemia) can
be caused by:
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Liver disease; cirrhosis of the liver is most common
Excess excretion by the kidneys (as in nephrotic syndrome)
Burns (plasma loss in the absence of skin barrier)
Redistribution (hemodilution [as in pregnancy], increased
vascular permeability or decreased lymphatic clearance)
Acute disease states (referred to as a negative acute-phase
protein)
Mutation causing an albuminemia (very rare)
• Hyperalbuminemia
1. this condition is a sign of severe or chronic
dehydration.
2. It is possible that a retinol (vitamin A) deficiency
alone could cause albumin levels to become raised.
Patients recovering from chronic dehydration may
develop dry eyes as the body uses up its vitamin A
store. It is interesting to note that retinol causes
cells to swell with water (this is likely one reason
that too much vitamin A is toxic)
3. Hyperalbuminemia is also associated with high
protein diets
How we do albumin analysis?
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Add 1 ml of albumin to Bromcresol (green) in the acidic
medium the green color transforms to a greenish to blue
color and the intensity of the color associated with
albumin concentration and that is measured by
spectrophotometric
Factors that affect analysis ?
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The result is higher if we draw the blood from the patient
standing or after exercise
In case of urinary infections and during the menstrual
cycle
After dialysis sessions
Globulin
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The globulins are a family of globular proteins that have
higher molecular weights and water solubility than
the albumins.
Globulin is made up of different proteins called alpha,
beta, and gamma types.
Some globulins are made by the liver, while others are
made by the immune system.
Certain globulins bind with hemoglobin and their
globulins transport metals, such as iron, in the blood and
help fight infection.
Serum globulin can be separated into several subgroups
by serum protein electrophoresis.
Globulin Can be separated into different fractions on the
basis of their electrophoretic mobility and
sedimentation coefficient:
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α1-Globulin
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α2-Globulin
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β-Globulin
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γ-Globulin
α1-Fetoprotein
α1-Antitrypsin
α2-Fetoprotein
Haptoglobin
Transferrin
Ceruloplasmin
Antibodies (immunoglobulins)
which include (Iga ,Igg ,Igm ,Ige)
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Alpha-1 globulin. The protein portion of high-density
lipoprotein (HDL), the “good” type of cholesterol, is
included in this fraction.
• Alpha-2 globulin. A protein called haptoglobin, that binds
with hemoglobin, is included in the alpha-2 globulin
fraction.
• Beta globulin. In addition to carrying substances through
the bloodstream, beta globulin proteins help fight
infection.
• Gamma globulin. This proteins is important in preventing
and fighting infection
Some gamma globulins bind to foreign substances (such
as virus or bacteria) and destroying them by the immune
system
High Globulin Levels caused by:
1. Chronic inflammatory diseases (ex: TB, Syphilis)
2. Bone marrow disorders like multiple myeloma
3. Leukemias
4. Autoimmunity (Systemic lupus, collagen diseases)
5. Rheumatoid arthritis
6. Liver disease (biliary cirrhosis, obstructive jaundice)
7. Carcinoid syndrome
8. Ulcerative colitis
9. Kidney disease (Nephrosis)
10.Chronic infections (parasites, some cases of viral and bacterial
infection like viral hepatitis or HIV)
Low Globulin Levels caused by:
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Hepatic dysfunction
Celiac disease
Proteins are not digested or absorbed properly
Inflammatory bowel disease (IBD)
Acute hemolytic anemia
Hypogammaglobulinemia/Agammaglobulinemia
Renal disease (A condition in which the kidneys do not filter the
protein from the blood and it leaks into the urine).
MEASUREMENT OF PROTEIN
FRACTIONS
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The protein fraction in plasma can be separated and estimated
using the following methods:
–Zone electrophoresis
–Immunochemical methods
–Chemical methods
–Ultracentrifugation
Ultracentrifugation
Physical Techniques
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1.Ultracentrifugation (analytical or Sedimentation
velocity ultracentrifuge) at 60,000 round per.min.
The boundary between the solvent and the protein is
visualized by an optical system –called (Sehlieren
System).
Advantage
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Most useful for the determination of the mol. wt of
proteins
Disadvantage
• High cost of each analysis and poor resolving capacity
(when applied to whole serum or plasma)
Serum protein electrophoresis
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This test measures specific proteins in the blood to help
diagnose some diseases.
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Proteins carry a positive or a negative electrical charge,
and they move in fluid when placed in an electrical field.
• Serum protein electrophoresis uses an electrical field to
separate the proteins in the blood serum into groups of
similar size, shape, and charge.
How to Prepare for the Test
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The patient may be asked not to eat or drink for 4 hours
before a serum protein electrophoresis test.
stop taking drugs that could affect the test. Do not stop
taking any medications without first talking health care
provider.
Drugs that can affect the measurement of total proteins
include
chlorpromazine,
corticosteroids,
isoniazid,
neomycin, phenacemide, salicylates, sulfonamides, and
tolbutamide.
How does it work?
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Blood must first be collected, usually into an airtight vial
or syringe.
Electrophoresis is a laboratory technique where the
blood serum is placed on special paper
The paper is exposed to an electric current to separate
the serum protein components into five classifications by
size and electrical charge, those being serum albumin,
alpha-1-globulins, alpha-2-globulins, beta globulins, and
gamma globulins.