Characterization of multiple platelet activation pathways in patients with bleeding as a high-throughput screening option: use of 96-well Optimul assay

Blood. 2014 Feb 20;123(8):e11-22. doi: 10.1182/blood-2013-08-520387. Epub 2014 Jan 9.


Up to 1% of the population have mild bleeding disorders, but these remain poorly characterized, particularly with regard to the roles of platelets. We have compared the usefulness of Optimul, a 96-well plate-based assay of 7 distinct pathways of platelet activation to characterize inherited platelet defects in comparison with light transmission aggregometry (LTA). Using Optimul and LTA, concentration-response curves were generated for arachidonic acid, ADP, collagen, epinephrine, Thrombin receptor activating-peptide, U46619, and ristocetin in samples from (1) healthy volunteers (n = 50), (2) healthy volunteers treated with antiplatelet agents in vitro (n = 10), and (3) patients with bleeding of unknown origin (n = 65). The assays gave concordant results in 82% of cases (κ = 0.62, P < .0001). Normal platelet function results were particularly predictive (sensitivity, 94%; negative predictive value, 91%), whereas a positive result was not always substantiated by LTA (specificity, 67%; positive predictive value, 77%). The Optimul assay was significantly more sensitive at characterizing defects in the thromboxane pathway, which presented with normal responses with LTA. The Optimul assay is sensitive to mild platelet defects, could be used as a rapid screening assay in patients presenting with bleeding symptoms, and detects changes in platelet function more readily than LTA. This trial was registered at as #ISRCTN 77951167.

Publication types

  • Observational Study
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adult
  • Blood Platelet Disorders / blood
  • Blood Platelet Disorders / diagnosis*
  • Blood Platelet Disorders / genetics
  • Blood Platelets / drug effects
  • Blood Platelets / physiology
  • Drug Monitoring / methods*
  • Female
  • Genetic Association Studies
  • Healthy Volunteers
  • Hemorrhage / blood
  • Hemorrhage / diagnosis*
  • Hemorrhage / physiopathology
  • High-Throughput Screening Assays / methods*
  • Humans
  • Male
  • Platelet Activation / drug effects
  • Platelet Activation / physiology*
  • Platelet Aggregation Inhibitors / pharmacology*
  • Predictive Value of Tests
  • Receptors, Thromboxane A2, Prostaglandin H2 / genetics
  • Sensitivity and Specificity
  • Young Adult


  • Platelet Aggregation Inhibitors
  • Receptors, Thromboxane A2, Prostaglandin H2

Associated data

  • ISRCTN/ISRCTN77951167