Sorted By Test Name - Mayo Medical Laboratories

TP
8520
TPSF
872
Protein, Total, Serum
Clinical Information: Plasma proteins are synthesized predominantly in the liver; immunoglobulins
are synthesized by mononuclear cells of lymph nodes, spleen and bone marrow. The 2 general causes of
alterations of serum total protein are a change in the volume of plasma water and a change in the
concentration of one or more of the specific proteins in the plasma. Of the individual serum proteins,
albumin is present in such high concentrations that low levels of this protein alone may cause
hypoproteinemia. Hemoconcentration (decrease in the volume of plasma water) results in relative
hyperproteinemia; hemodilution results in relative hypoproteinemia. In both situations, concentrations of
all the individual plasma proteins are affected to the same degree. Hyperproteinemia may be seen in
dehydration due to inadequate water intake or to excessive water loss (eg, severe vomiting, diarrhea,
Addison's disease and diabetic acidosis) or as a result of increased production of proteins. Increased
polyclonal protein production is seen in reactive, inflammatory processes; increased monoclonal protein
production is seen in some hematopoeitic neoplasms (eg, multiple myeloma, Waldenstrom's
macroglobulinemia, monoclonal gammopathy of undetermined significance).
Useful For: Total protein measurements are used in the diagnosis and treatment of a variety of diseases
involving the liver, kidney, or bone marrow, as well as other metabolic or nutritional disorders.
Interpretation: Mild hyperproteinemia may be caused by an increase in the concentration of specific
proteins normally present in relatively low concentration, eg, increases in acute phase reactants and
polyclonalimmunoglobulins produced in inflammatory states, late-stage liver disease, and infections.
Moderate-to-marked hyperproteinemia may also be due to multiple myeloma and other malignant
paraproteinemias, although normal total protein levels do not rule out these disorders. A serum protein
electrophoresis should be performed to evaluate the cause of the elevated serum total protein.
Hypoproteinemia may be due to decreased production (eg, hypogammaglobulinemia) or increased protein
loss (eg, nephrotic syndrome, protein-losing enteropathy). A serum protein electrophoresis should be
performed to evaluate the cause of the decreased serum total protein. If a nephrotic pattern is identified,
urine protein electrophoresis should also be performed.
Reference Values:
> or =1 year: 6.3-7.9 g/dL
Reference values have not been established for patients that are less than 12 months of age.
Clinical References: 1. Tietz Textbook of Clinical Chemistry. Edited by CABurtis, ER Ashwood.
Philadelphia, WB Saunders Company, 1994 2. Killingsworth LM: Plasma proteins in health and disease.
Crit Rev Clin Lab Sci 1979;11:1-30
Protein, Total, Spinal Fluid
Clinical Information: Cerebral spinal fluid (CSF) is secreted by the choroid plexuses, around the
cerebral vessels, and along the walls of the ventricles of the brain. It fills the ventricles and cisternae,
bathes the spinal cord, and is reabsorbed into the blood through the arachnoid villi. CSF turnover is rapid,
exchanging about four times per day. More than 80% of CSF protein content originates from plasma by
ultrafiltration through the walls of capillaries in the meninges and choroid plexuses; the remainder
originates from intrathecal synthesis. Because CSF is mainly an ultrafiltrate of plasma, low-molecular
plasma proteins such as prealbumin, albumin, and transferrin predominate. No protein with a molecular
weight greater than that of IgG is present in sufficient concentration to be visible on electrophoresis. The
permeability of the blood-brain barrier to plasma proteins is increased by high intracranial pressure due to
brain tumor; intracerebral hemorrhage; traumatic injury; or by inflammation due to bacterial or viral
meningitis, encephalitis, or poliomyelitis. Increased intrathecal synthesis of immunoglobulins, particularly
IgG, is seen in demyelinating diseases of the central nervous system (CNS), especially multiple sclerosis.
Increased immunoglobulins are also seen in other chronic inflammatory diseases of the CNS such as
chronic meningoencephalitis due to bacteria, viruses, fungi or parasites; subacute sclerosing
panencephalitis; and Guillian-Barre syndrome.
Useful For: To detect increased permeability of the blood-brain barrier to plasma proteins To detect
increased intrathecal production of immunoglobulins
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