protein electrophoretogram Flashcards
Fraction: Pre-albumin
prealbumin
Function: pre-albumin
- Transport protein for thyroid hormones (transthyretin)
Pos or neg APR: Pre-Albumin
Neg (decreases during inflammation)
Condition(s) in which it ↓: Pre-Albumin
Malnutrition (sensitive marker of protein nutritional status)
Fraction: Albumin
Albumin
Function: Albumin
- Maintains fluid balance between blood and interstitial fluid by contributing 80% of colloidal osmotic (oncotic) pressure of intravascular fluid
- Transports insoluble substances in blood
Pos or Neg APR: Albumin
neg (decreases in inflammation)
Condition(s) in which it ↓: Albumin
- Decreased synthesis (malnutrition, liver failure, acute inflammation or infection (Neg APR))
- Increased loss (nephrotic syndrome)
- Causes edema when serum Alb is < 2.5 g/dL Edema: excessive accumulation of interstitial fluid
Conditions in which it ↑ if applicable: Albumin
dehydration
Fraction: alpha-1-antitrypsin
alpha 1
Function: alpha-1-antitrypsin
- major protein of ⍺1 fraction
- A trypsin inhibitor that prevents over-catabolism of structural protein in the lung
Pos or neg APR: alpha-1-antitrypsin
Pos (increases during inflammation)
Condition(s) in which it ↓ if applicable: alpha-1-antitrypsin
- in congenital alpha-1-antitrypsin deficiency
- Causes pulmonary emphysema
Fraction: alpha-1-fetoprotein
alpha 1
Function: alpha-1-fetoprotein
- principal fetal protein
- synthesized by developing embryo & fetal liver
Condition(s) in which it ↓ if applicable: alpha-1-fetoprotein
- Decrease in maternal blood: Down Syndrome
Conditions in which it ↑: alpha-1-fetoprotein
- Increased in maternal blood: spinal bifida, or open neural tube defect
- If present in adult serum: hepatocellular carcinoma, germ cell tumors (ie. testicular cancer)
Fraction: Haptoprotein
alpha 2
Function: Haptoglobin
- A glycoprotein and a major component of ⍺2 fraction
- Binds free Hgb (but not Mgb) during intravascular hemolysis
- HAP-Hgb complex cleared by reticulo-endothelial cells (prevents renal loss of Hgb)
Pos or Neg APR: Haptoglobin
Pos (increased during inflammation, infection, or malignancy)
Condition(s) in which it ↓: Haptoglobin
Decreased in intravascular hemolysis → sensitive indicator of intravascular hemolysis
Fraction: alpha-2-macroglobulin
alpha 2
Function: alpha-2-macroglobulin
- A major component of ⍺2 fraction
- The largest non-immunoglobulin protein in plasma
- Is a protease inhibitor, inhibits variety of proteinases (trypsin, thrombin, kallikrein & plasmin)
Conditions in which it ↑: alpha-2-macroglobulin
– Increased: in nephrotic syndrome, Increased synthesis to maintain oncotic pressure due to loss in albumin
Fraction: ceruloplasmin
alpha 2
Function: Ceruloplasmin
- Is a Cu transport protein, binds 90% of body copper (Cu), prevents its deposition in organs
- Also a Cu-containing oxidase enzyme
Regulates Fe absorption, transport & utilization by oxidizing Fe2+ to Fe3+ (only Fe3+ can bind to transferrin & be stored in ferritin)
Pos or neg APR: ceruloplasmin
Pos (increases during inflammation)
Condition(s) in which it ↓: ceruloplasmin
- Menkes syndrome (congenital, kinky hair Dz)
Impaired intestinal absorption of Cu2+, Serum Cu2+ ↓ - Wilson’s Dz (congenital, Kayser-Fleischer rings)
Cu2+ cannot be incorporated into Cp → toxic deposits of Cu2+ in tissues → damage, esp liver & brain
Serum Cu2+ ↓, urine Cu2+ ↑ & biopsy liver Cu2+ positive
Fraction: transferrin
beta
Function: transferrin
The major component of the β fraction
Transports Fe3+ to bone marrow, liver, & RE cells for storage by ferritin
Pos or neg APR: transferrin
Neg (decreases in inflammation)
Conditions in which it ↑: transferrin
Iron deficiency anemia (compensatory mechanism to enhance Fe absorption)
Fraction: beta-2-microglobulin
beta
Function: beta-2-microglobulin
- A light chain of the MHC (major histocompatibilit y complex) found on the surface of most nucleated cells; esp. high on lymphocytes
- Functions to present Ags to cytotoxic T lymphocytes
Condition(s) in which it ↓: Beta-2-microglobulin
- increased cellular destruction (leukemia, MM, or renal transplant rejection) → urine levels also increase
- Renal failure (↓ GFR) → urine levels ↓
Conditions in which it ↑: Beta-2-microglobulin
Decrease (often normal) in blood but increased in urine
Suggests renal tubular Dz (↓ reabsorbed & catabolized by RTE)
Fraction: Complement proteins, C3 & C4
beta
Function: Complement proteins, C3 & C4
identify, destroy and remove foreign pathogens and damaged ‘self’ materials
Pos or Neg APR: Complement Proteins, C3 & C4
Pos (increase during inflammation + certain types of cancer)
Condition(s) in which it ↓: Complement proteins, C3 & C4
- Autoimmune disease (lupus, rheumatologic)
- Recurrent infection (usually bacterial)
- Others: immune complex-induced renal Dzs
Fraction: fibrinogen
beta-gamma interzone
Function: fibrinogen
Functions in thrombosis
Pos or Neg APR: fibrinogen
Pos (increases during inflammation)
Condition(s) in which it ↓: fibrinogen
Disseminated intravascular coagulation (DIC)
Fraction: C-reactive protein
- Involved in innate immunity by activating complement → enhances phagocytosis of bacteria & fungi
- is the most sensitive APR, compared to other APRs (HAP & C3,C4), it rises the fastest & highest
Pos or Neg APR: C-reactive protein
Pos (increased during inflammation)
Conditions in which it ↑: C-Reactive Protein
Infection or inflammation (a key inflammatory marker)- CRP test Cardiovascular Dz (a marker for cardiovascular Dz risk)- hs-CRP (high sensitive)
Fraction: Immunoglobulins
gamma
Function: immunoglobulins
Produced by plasma cells in blood & lymph in response to infection
Pos or Neg APR: Immunoglobulins
Pos
Condition(s) in which it ↓: Immunoglobulins
immunodeficiency: congenital or acquired (HIV)
Conditions in which it ↑: Immunoglobulins
- Polyclonal gammopathy → broad peak
o Infection or chronic inflammatory conditions
- Monoclonal gammopathy → single sharp peak
o Multiple Myeloma: IgG, IgA, IgM rare
o Waldenstrom’s macroglobuline mia: IgM
