Acute phase protein (Acute Phase Reactants)
- Acute phase protein is raised in the inflammatory conditions.
- When there is increased in a protein called positive acute phase protein.
- In the case of a decrease in the acute phase protein, is called negative phase protein.
- The acute phase proteins (positive) are protein whose concentration increases in the plasma and after the disease episode is over then it decreases and may become normal.
- The blood sample of the patient is needed.
- The serum is needed to perform the test.
- Can store for 2 weeks at -20 °C.
- This test is done to detect intravascular hemolysis.
- Avoid the hemolyzed sample.
- This is α-2 glycoprotein and binds Hemoglobin irreversibly.
- This is a free Hb binding protein.
- Transport the free hemoglobin through blood to the liver for degradation.
- Free hemoglobin is bound to α-chain of the haptoglobin.
- This is present in the α-2 zone on electrophoresis.
- Haptoglobin increases from the mean value of 0.02g/L at birth to an adult level within the first year of life.
- It increases with the increasing age.
- This is synthesized in the liver and consists of four peptide chains linked by a disulfide bond.
- There are three possible alpha (α) chains and only one β-chain.
- It binds free hemoglobin and is rapidly cleared from the blood in case of intravascular hemolysis.
- In the initial stage of the hemolysis, the liver can compensate for the synthesis of HP, so its level is decreased.
- This is increased in acute and chronic inflammation.
- It is a natural bacteriostatic agent for iron-requiring bacteria e.g. E.coli.
- This is acute phase protein increased in ulcerative colitis, acute rheumatic diseases and heart attack.
- This is helpful to differentiate hemolytic anemia from the other causes of anemia.
- Haptoglobin is markedly increased plus when Reticulocytes are increased indicates intravascular hemolysis.
- Intravascular hemolysis = Increased haptoglobin + Increased reticulocytes.
- Haptoglobin is normal or slightly decreased plus Reticulocytes are increased indicate extravascular hemolysis in the liver or spleen.
- Extravascular hemolysis = Haptoglobin normal + Increased reticulocytes.
- Haptoglobin is normal plus Reticulocytes are not increased indicate decreased production of the RBC from bone marrow.
- Bonemarrow depression = Haptoglobin normal + reticulocytes not increased.
- Haptoglobin depletion is a sensitive marker for the hemolysis.
- HP is decreased in the hemoglobinuria.
- HP is unchanged in the myoglobinuria and rhabdomyolysis because there is no binding with HP.
- Newborn = 5 to 48 mg/dL
- 6 months to 16 years = 25 to 138 mg/dL
- 16 to 60 years = 15 to 200 mg/dL
- >60 years = 35 to 175 mg/dL
- Another source
- Adult = 20 to 220 mg/dL
- Newborn = 0 to 10 mg/dL
- Critical value = <40 mg /dL
The increased level is seen in:
- By corticosteroids hormones and nonsteroidal anti-inflammatory drugs.
- In nephrotic syndrome.
- In biliary obstruction in absence of hepatocellular disease.
- Ulcerative colitis.
- peptic ulcer.
- Acute rheumatic disease.
- In cancers.
- In acute and chronic inflammatory disease and it acts as acute phase protein.
- In acute myocardial infarction.
- In tissue destruction like burn, and cancers.
- Drugs that may increase the level are:
The decreased level is seen in:
- In hemolytic anemia.
- Systemic lupus erythematosus
- Erythroblastosis fetalis.
- Estrogen will decrease its synthesis.
- Decreased with severe liver diseases.
- The slight decrease in blood transfusion even in the compatible blood transfusion due to the presence of a few RBC hemolysis.
- This may be decreased in hematoma because of the binding of Hb with HP.
- Drugs that may decrease the level are:
- Oral contraceptives.
Critical value is <40 mg/dL.
Possible References Used
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