Serum Haptoglobin Level Testing
Serum Haptoglobin Level Testing
Haptoglobin is an acute-phase protein that binds free hemoglobin in plasma. Its measurement is crucial in evaluating hemolytic conditions in pediatric patients.
Key Points
- Essential marker for detecting intravascular hemolysis
- Acute phase reactant protein
- Binds and removes free hemoglobin from circulation
- Levels vary significantly with age and conditions
Basic Physiology
Haptoglobin Structure and Function
- α2-glycoprotein synthesized in liver
- Forms stable complexes with free hemoglobin
- Prevents hemoglobin-induced oxidative damage
- Helps conserve iron during hemolysis
Normal Physiology
- Production:
- Synthesized primarily in hepatocytes
- Production increases during inflammation
- Gene expression regulated by cytokines
- Metabolism:
- Half-life: 3-5 days
- Cleared through reticuloendothelial system
- Levels affected by liver function
Testing Methods
Sample Requirements
- Serum preferred over plasma
- Fasting sample recommended
- Avoid hemolyzed specimens
- Process within 4 hours of collection
Analytical Methods
- Immunonephelometry:
- Most common method
- Automated analysis
- Quick turnaround time
- Immunoturbidimetry:
- Alternative automated method
- Good precision and accuracy
- Cost-effective
- Radial Immunodiffusion:
- Reference method
- Time-consuming
- Higher precision
Clinical Applications
Primary Indications
- Suspected hemolytic anemia
- Monitoring known hemolytic disorders
- Evaluation of unexplained anemia
- Assessment of transfusion reactions
Specific Clinical Scenarios
- Hemolytic Conditions:
- Autoimmune hemolytic anemia
- Hereditary spherocytosis
- Sickle cell disease
- Thalassemia syndromes
- Other Applications:
- Liver disease assessment
- Inflammatory conditions
- Monitoring treatment response
Result Interpretation
Reference Ranges
- Newborns: 20-150 mg/dL
- Infants (1-6 months): 30-200 mg/dL
- Children: 30-200 mg/dL
- Adolescents: 40-240 mg/dL
Decreased Levels
- Hemolytic Conditions:
- Intravascular hemolysis
- Acute hemolytic crisis
- Transfusion reactions
- Non-Hemolytic Causes:
- Liver disease
- Genetic anhaptoglobinemia
- Malnutrition
Increased Levels
- Inflammatory Conditions:
- Acute infections
- Tissue damage
- Malignancy
- Other Causes:
- Steroid therapy
- Nephrotic syndrome
- Obesity
Interpretation Pitfalls
- Consider acute phase response
- Account for recent transfusions
- Evaluate alongside other hemolysis markers
- Consider genetic variations
