Clinical Applications of Serum Proteins Part 1
Terms in this set (76)
Normal values for total protein.
Normal values for albumin.
Normal values for alpha-1 globulins.
Normal values for alpha-2 globulins.
Normal values for beta globulins.
Normal values for gamma globulins.
General issues that may cause hyperproteinemia (3).
2. monoclonal diseases, e.g. multiple myeloma
3. chronic polyclonal disease e.g. liver cirrhosis, lupus
General issues that may cause hypoproteinemia (7).
1. inadvertent overhydration
2. protein loss thru kidneys e.g. nephrotic syndrome
3. thermal burns
4. decreased intake via diet or GI obstruction
5. malabsorption conditions e.g. sprue
6. increased protein catabolism as in fevers, necrosis, cancer, steroid treatment
7. increased protein requirement for situations such as pregnancy, growth, hyperthyroidism
When might hyperalbuminemia be observed?
In cases of acute dehydration or shock
What disease states are associated with increased globulin levels (5)?
1. monoclonal diseases
2. some forms of liver disease
4. collagen diseases
5. chronic infection
What are diseases associated with decreased globulin levels known as?
What is the old name for transthyretin?
What is the function of transthyretin?
What are some examples of analytes transthyrtein transports?
T4 and T3 hormones
What fluids might transthyretin be found in?
Blood and CSF
List 3 causes for increased transthyretin levels.
1. Hodgkin's lymphoma
2. Cerebral atrophy
3. Drugs such as aspirin or glucocorticoids
List the 4 major functions of albumin.
1. Osmotic pressure regulation
2. Transportation of analytes
3. Endogenous source of amino acids
4. Buffers pH of blood due to osmotic properties
Measurement of this protein is used to evaluate nutritional status of patients.
This protein accounts for 90% of the alpha 1 region on SPE
This protein acts as a serine protease inhibitor to prevent inappropriately severe response to inflammation, especially in the lungs.
What is the most important inhibitor of leukocyte elastase? What does inhibition of leukocyte elastase prevent?
AAT; it prevents damage to surrounding tissue when LE is released from phagocytizing neutrophils
Why might a genetic deficiency of alpha-1-antitrypsin result in pulmonary emphysema?
AAT normally prevents proteases from damaging lung mucosa; without it, the lung damage caused results in emphysema
What might cause an acquired deficiency of alpha-1-antitrypsin?
Why might alpha-fetoprotein measurements be taken? What makes these measurements controversial?
Since AFP can cross the placenta, AFP levels can indicate fetal conditions such as Down's syndrome, multiple fetuses, intrauterine death or fetal distress, etc. Use of these measurements for diagnostic purposes is controversial due to the numerous immeasurable factors, i.e. how fast the fetus is growing
Alpha-1-acid glycoprotein is also known as...
This protein binds and inactivates basic and lipophilic hormones such as progesterone, and reduces the bioavailability of some drugs, such as propanolol, quinidine, and cocaine.
Clinical significance of an increased AFP in maternal serum (4).
1. open neural tube or abdominal wall defects
2. multiple fetuses
4. fetal distress/intrauterine death
Clinical significance of presence of AFP in children and adults.
It is a cancer marker for hepatocellular and germ cell carcinomas.
List four causes for increased levels of alpha-1-acid glycoprotein.
1. Inflammatory response, especially GI (ulcerative colitis monitoring)
2. Autoimmune diseases
Monitoring AAG levels is a good way to test for the status of ___________.
GI inflammatory diseases such as ulcerative colitis.
What might cause decreased levels of AAG? (3)
1. Presence of estrogens (pregnancy, oral contraceptives)
2. Genetic variants
3. Protein losing syndrome
List the 3 alpha-2-globulins.
What protein classification is the largest in molecular size?
This protein class inhibits different classes of proteases by coupling with the proteases, thus altering their configuration and allowing clearance by the RE.
Streptokinase therapy may cause a decrease in this area of an SPE.
List three disease states in which A2G levels are increased.
1. Rheumatoid arthritis
2. Multiple myeloma
3. Severe acute pancreatitis
What causes an increased level of A2G proteins? (3)
1. A relative increase due to loss of other proteins
2. Nephrotic sydnrome
3. Thermal burns
Are A2Globulin levels higher in men or women?
Why do A2G levels increase in nephrotic syndrome?
Hepatic synthesis of all serum proteins increases to compensate for the loss of LMWP.
The primary function of haptoglobin.
Haptoglobin binds to free hemoglobin to transport to the RE system, preventing iron damage to the kidney tubules.
List 4 causes of decreased haptoglobin levels.
1. hemolytic anemia
3. liver disease
4. congenital haptoglobin deficiencies
List 4 causes of increased haptoglobin levels.
1. Positive APR
2. Relative increase with burns or nephrotic syndrome
3. Corticosteroid hormones and NSAIDS
4. Biliary obstruction in the absence of hepatocellular disease
What serum protein contains approximately 95% of total serum copper in the body?
What might give serum a greenish appearance?
High levels of ceruloplasmin; the saturated protein is colored blue, and thus turns the straw colored plasma green.
What is the primary physiological role of ceruloplasmin?
It functions as an oxidative enzyme; oxidizes Fe2 to Fe3 at the cell surface so that it can be transported by transferrin; also thought to inhibit spontaneous oxidation of organic substances such as free radicals.
What is the name of the disease caused by a congenital deficiency of ceruloplasmin?
Three tissues where unbound copper is deposited.
Two physical manifestations of Wilson's disease.
1. Parkinsonism type movements
2. Golden-brown pigmentation around the cornea of the eyes
List the three diagnostic features of Wilson's disease.
1. Golden-brown rings encircling the cornea
2. Copper content in excess of 250 mg/g of dry liver biopsy specimen
3. Increased urinary excretion of copper with a decreased ceruloplasmin (<30 mg/dL) and serum copper concentration
Acquired ceruloplasmin deficiency is primarily associated with ________.
Three causes of increased ceruloplasmin levels.
1. Positive APR
2. Oral contraceptives and pregnancy
3. Biliary obstruction
List the 4 beta globulins.
Function of transferrin.
Transportation of free iron in the blood.
The normal percent of transferrin that is typically saturated with iron.
How are total transferrin levels measured?
Using the total iron binding capacity, which refers to the total amount of iron that can be bound by the transferrin available in the blood stream.
Five potential causes of decreased transferrin levels.
1. Negative APR
2. Liver disease
3. Protein loss (nephrotic syndrome or enteropathy)
4. Congenital atransferrinemia
5. Nonspecific malnutrition
The two main causes of increased transferrin.
2. Pregnancy and estrogen therapy that decrease iron levels
The form of transferrin only found in spinal fluid.
What is the clinical significance of Tau protein?
Tau protein migrates differently on SPE than does blood transferrin, and thus measurement of Tau protein can be used to determine if fluid is CSF.
What could severe IDA resemble on SPE?
The abnormally tight, thick zone created by elevated transferrin levels may be mistaken for a monoclonal abnormality.
Beta lipoprotein is also known as...
What complement component is present in the highest concentration of all the complement components in plasma?
Three causes of elevated C3 levels.
1. Mild positive APR
2. Biliary obstruction
3. Focal glomerulosclerosis (favorable prognosis)
What are four causes of decreased C3 levels?
1. Genetic deficiency
2. Autoimmune disorders
4. Recurrent infection
What is the clinical significance of decreased hemopexin levels?
When might increased hemopexin levels be seen? (2)
The class of immunoglobulin produced as a first response to the presence of a new antigen.
The class of immunoglobulin produced primarily by mucous membranes of the gut to protect mucosa from bacteria and viruses.
The class of immunoglobulin that primarily functions to neutralize toxins in tissue spaces; it is also produced in "memory" response upon second exposure to an antigen.
A decrease in the gamma region of SPE is usually caused by these three mechanisms.
1. Defective synthesis
2. Excessive loss
3. Increased catabolism
What is the term for an increased gamma region on an SPE?
If there is an increase in the gamma region of an SPE, what is the next step in diagnostic testing?
Run an immunofixation electrophoresis, or other method, and quantification of specific immunoglobulins.
What is the purpose of an immunofixation electrophoresis?
To determine if the abnormality is polyclonal or monoclonal.
What is the purpose of quantifying specific immunoglobulins?
The protein profile established from the quantification can be compared with known protein profiles associated with certain pathologic conditions.
Where does fibrinogen migrate on SPE?
Between the beta and gamma regions.
What two proteins can be used to prove specimen is CSF and not serum?
2. Tau protein (CSF version of ferritin)