Pooled Platelets: How do they compare?

Carter BloodCare has been working diligently to produce additional pooled platelets for our community. This is a way for us to strengthen our platelet supply, as it enables us to produce more platelet doses from the whole blood donations we are already collecting. We have always made pooled platelets, but we have recently increased our production by five times in the past few years. These additional platelet products have already helped us get through what would have previously been periods of temporary platelet shortage with much less impact on our platelet inventory. Therefore, if you are not using these products in your hospital, we encourage you to do so.

But, how do pooled platelets compare to our traditional apheresis platelets? Carter BloodCare’s pooled platelets are made up of a pool of four or five whole blood-derived platelets. Each pool, whether a four- or five-unit pool, has a minimum yield of >2.8x1011. These are room temperature platelets only, bacterially tested and have a seven-day shelf life – just like our apheresis platelets.

Historically, there have been some concerns about using pooled platelets because of increased donor exposure. However, studies have shown that these concerns are not supported by scientific literature. In fact, studies have shown that bacterial contamination risk is equivalent to apheresis platelets¹, and risk of viral transmission (HIV, hepatitis B and C) is balanced when compared to apheresis platelets². This is thought to be due to the longer interdonation period for whole blood, which makes it less likely for a donor to donate during the window period of viral infection, and, therefore, balances the risk associated with pooled products². The potential concern for increased risk of HLA alloimmunization has also been debunked as the TRAP study showed that apheresis platelets conferred no benefit over pooled platelets in the development of immune-mediated platelet refractoriness³.

Additionally, there may be some benefits of using pooled platelets over apheresis platelets. Transfusion of pooled platelets has been found to have decreased overall and severe adverse reaction rates⁴. This is thought to be due to dilution of plasma components in the pooled products compared to apheresis products. Finally, a small study showed that pooled platelets may confer a benefit to patients with platelet refractoriness compared to apheresis platelets⁵.

In summary, we are confident that pooled platelets are equivalent in both safety and efficacy when compared to apheresis platelets, and pooled platelets even have some benefits that should be recognized.

1.    Schrezenmeier H, G Walther-Wenke,* TH Müller et al. Bacterial contamination of platelet concentrates: results of a prospective multicenter study comparing pooled whole blood–derived platelets and apheresis platelets. Transfusion 2007;47:644-652

2.    M. an der Heiden, S. Ritter, O. Hamouda & R. Offergeld, Estimating the residual risk for HIV, HCV and HBV in different types of platelet concentrates in Germany. Vox Sanguinis 2015: 108, 123–130.

3.    TRAP Study Group. Leukocyte reduction and ultraviolet B irradiation of platelets to prevent alloimmunization and refractoriness to platelet transfusions. New England Journal of Medicine 1997; 337(26):1861-1869.

4.    Daurat A, C Roger, JC Gris et al. Apheresis platelets are more frequently associated with adverse reactions than pooled platelets both in recipients and in donors: a study from French hemovigilance data. Transfusion 2016; 56; 1295–1303

5.    Chu Y, W Rose, W Nawrot, T Raife. Pooled platelet concentrates provide a small benefit over single-donor platelets for patients with platelet refractoriness of any etiology. Journal of International Medical Research 2021: 49(5) 1–8