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What tests for qualitative platelet function defects do we have available, and how can they influence management in clinic?

Current as of 17 July 2026 · added 17 July 2026

Answer: A tiered set of assays — from a whole-blood screen to disorder-specific confirmatory tests.

  • PFA-100/200: originally developed to replace the bleeding time, now used to screen for platelet function defects. Whole blood is aspirated at high shear through cartridges with a membrane coated with either collagen/epinephrine or collagen/ADP; shear stress drives adhesion, activation, and aggregation. Pros: small volume, automated, good screening, relatively insensitive to clotting factor deficiency, high NPV — with exceptions (storage pool disease, secretion defect, type 1 VWD).
  • Flow cytometry: detects surface membrane glycoproteins; most commonly to identify lack of CD41/CD61 (Glanzmann thrombasthenia) or CD42b (Bernard-Soulier).
  • Light transmission aggregometry (LTA).
  • VerifyNow (intra-operative).
  • Other tests: electron microscopy / nucleotide assays (not very helpful clinically), and the platelet procoagulant activity assay (e.g. Scott syndrome).
  • Genetic testing: an evolving topic.

Source: Platelet function testing — introduction (Practical-Haemostasis)