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Example(s) of typical appearance
Example(s) of a change in appearance

Particulate matter can be the result of blood collection and/or component manufacturing processes. There are several categories of particulate matter that may be found within platelet units: 

  • Clots and fibrin strands  
    • Clots may appear as white and opaque masses that do not dissipate with gentle manipulation. 
    • Clots and fibrin strands result from the activation of the clotting processes and can be a mixture of clotting proteins (including fibrin) and platelets. Blood is collected and processed in bags that contain anticoagulants to inhibit the clotting processes. Blood components containing clots and / or fibrin strands should NOT be transfused and should be reported to Canadian Blood Services. 
  • Aggregates 
    • Aggregates may appear as small white and opaque masses that generally dissipate with gentle manipulation and/or agitation. 
    • Aggregates have been reported in some pathogen-reduced platelet components. Platelets containing visible particles are not inferior to particle-free concentrates.  
    • Placing units in landscape orientation on an agitator may help reduce aggregate formation.  


A close up view of a platelet unit with small white dots near the bottom of the bag.
An example of a platelet unit with white particulate matter.