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Clinical Pathology Laboratory - Available Test
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Electrophoresis Components
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| The electrophoretogram splits the protein fraction of serum or plasma
into its constituent components. There are three globulin fractions:
alpha, beta and gamma. |
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Total protein: |
- This is measured on the Hitachi using the biuret method (serum,
plasma, body fluids) or turbidometry (CSF, urine). A total protein
concentration is necessary to provide absolute values (not just
percentages) of the protein components.
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Albumin: |
- Albumin is the first peak on the electrophoretogram and is usually
a tall thin peak. The albumin concentration by ELP is usually
lower than that from the Hitachi.
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Alpha (a) globulins: |
- These migrate next to albumin and are synthesized in the liver.
They include the acute phase reactant proteins, a-2 macroglobulin
and haptoglobulin. In most species, a-globulins can be split into
two main components, a1 and a2, although further subdivisions
are present in some species or individual animals.
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Beta (b) globulins: |
- These migrate between g- and a-globulins. They are usually produced
in the liver and include fibrinogen (plasma), transferrin and
complement components. Like a-globulins, b-globulins can be divided
into two major components (b1 and b2) in most species, although
further subdivisions are evident (e.g. dogs usually have b1a and
b1b).
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Gamma globulins: |
- This comprises the immunoglobulins, IgG, IgA and IgM and is
the furthest peak from albumin. In reality, IgA and IgM often
migrate in the late b- (b2-region) or early g-region. The shape
of the g-peak provides diagnostic information. A broad-based peak
indicates a polyclonal gammopathy (see panel B below), which is
usually due to antigenic stimulation and is not disease specific.
A tall sharp peak in the g-region or late b-region is compatible
with a monoclonal gammopathy. Samples displaying such electrophoretograms
should be evaluated further, by individually quantifying the immunoglobulins,
to determine which immunoglobulin is producing the monoclonal
peak. Monoclonal peaks are usually due to neoplastic disorders,
e.g. multiple myeloma, but can occur as a reactive phenomenon,
e.g. Ehrlichia canis infection in dogs.
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Different electrophoretogram patterns in serum
Panel A: Normal agarose gel electrophoretogram in a dog. The tallest
peak to the left is albumin, followed by a1 (2 peaks), a2 (2 peaks),
b1 (2 peaks of b1a and b1b), b2 and g (the last flat peak).
Panel B: Serum from a cat with feline infectious peritonitis virus
(FIPV) infection. There is an increase in a-2 globulins (arrowhead),
indicating an acute phase reactant response, and a polyclonal gammopathy
(arrow). These results are typical, but not specific, for FIPV infection
(they can be seen with other inflammatory conditions).
Panel C: Serum from a dog with multiple myeloma. There is a tall narrow
peak in the g-region, indicating a monoclonal gammopathy (arrow).
Albumin concentrations are also decreased (compare to the normal dog
in panel A). |
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