A number of platelet types are available at Canadian Blood Services (acronyms are further described in the terminology table):

Because platelet units consist of platelets resuspended in plasma or plasma and platelet additive solution (PAS), they are opaque and vary in colour from beige to yellow. Residual RBCs in platelet units may cause a pink or marked red colouring. There are several conditions or characteristics that are associated with a change in appearance of platelet units. Whether or not a blood component is suitable for transfusion is determined by local hospital policy and procedures.

Post-production manufacturing such as irradiation does not significantly change the appearance of platelet units but will affect the label. 

 

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Two platelet units side-by-side.
Source: Blais-Normandin I, Tordon B, Anani W, Ning S. Pathogen-reduced platelets. In: Khandelwal A, Abe T, editors. Clinical Guide to Transfusion [Internet]. Ottawa: Canadian Blood Services, 2022. Chapter 19. Available from: https://professionaleducation.blood.ca

 

Image
Three types of platelet units side-by-side.
Source: Blais-Normandin I, Tordon B, Anani W, Ning S. Pathogen-reduced platelets. In: Khandelwal A, Abe T, editors. Clinical Guide to Transfusion [Internet]. Ottawa: Canadian Blood Services, 2022. Chapter 19. Available from: https://professionaleducation.blood.ca

 

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A close up view of a swirl of yellow liquid near the edge of a bag.
Swirl may be observable in a typical platelet unit. 

 

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A close up view of a swirl of yellow liquid near the bottom of a platelet unit.
Another example of a swirl observable in a typical unit of pooled platelets.