Platelet Function Analysis (PFA-100)
Platelet Function Analysis (PFA-100)
Key Points
- Point-of-care test for platelet function screening
- Mimics in vivo platelet plug formation
- Evaluates platelet adhesion and aggregation
- Useful for detecting platelet disorders
- Complements traditional coagulation testing
Overview
The PFA-100 is an automated instrument that provides a global assessment of platelet function under high shear stress conditions. It is a widely used screening tool for evaluating platelet disorders and platelet-related bleeding tendencies in pediatric patients.
Test Methodology
- Sample Collection
- Citrated whole blood sample
- Specific collection tube requirements
- Prompt processing within 4 hours
- Measurement Principle
- Aspiration of blood through a microscopic aperture
- Platelet adhesion and aggregation under high shear
- Time to obstruct aperture (closure time) measured
- Cartridge Types
- Collagen/Epinephrine (CEPI)
- Collagen/ADP (CADP)
- Selects different platelet activation pathways
Technical Considerations
- Instrument maintenance and calibration
- Operator training and competency
- Quality control procedures
- Result reproducibility and precision
Primary Uses
- Screening for platelet function disorders
- von Willebrand Disease
- Glanzmann's Thrombasthenia
- Bernard-Soulier Syndrome
- Assessment of platelet inhibitor effects
- Antiplatelet medications
- Uremia-associated platelet dysfunction
- Monitoring therapeutic responses
- Preoperative evaluation of bleeding risk
- Identification of previously unknown disorders
- Guidance for hemostatic management
- Postoperative monitoring
Emerging Applications
- Early detection of neonatal platelet disorders
- Monitoring of congenital platelet function defects
- Assessment of platelet function in thrombotic disorders
- Evaluation of platelet function in critically ill children
Age-Specific Reference Ranges
- Neonates (0-30 days)
- CEPI-CT: 84-193 sec
- CADP-CT: 71-146 sec
- Infants (1-12 months)
- CEPI-CT: 82-165 sec
- CADP-CT: 68-128 sec
- Children (1-16 years)
- CEPI-CT: 79-165 sec
- CADP-CT: 62-116 sec
Developmental Considerations
- Platelet count and function maturation
- Physiological changes in platelet receptors
- Hormonal influences on platelet reactivity
- Importance of age-appropriate reference ranges
Interpretation of Closure Times
- Prolonged CEPI-CT
- Acquired or inherited platelet disorders
- Von Willebrand Disease
- Antiplatelet medication effects
- Prolonged CADP-CT
- Platelet secretion or aggregation defects
- Bernard-Soulier Syndrome
- Glanzmann's Thrombasthenia
- Elevated Closure Times
- Increased bleeding risk
- Need for further coagulation testing
- Consideration of prophylactic treatment
Limitations and Caveats
- Reduced sensitivity for mild platelet disorders
- Potential interference from hematocrit, medications
- Lack of consensus on optimal reference ranges
- Need for correlation with clinical presentation
