Thrombocyte concentrates are used frequently, especially for treating thrombocytopenia (too low platelet count) after chemotherapy and generally in the context of malignant diseases. In patients with a chronic platelet need, apheresis concentrates are preferred to minimise the recipients' exposure. They are obtained from a single donor and are particularly suitable for patients already immunised - either by HLA-antibodies or platelet antibodies.

In general, platelet concentrates can be prepared in two ways.

When it comes to collecting platelets for transfusion, there are two main methods: pooling 4-8 buffy coats or using single donation through platelet apheresis. Both methods are equally effective. However, pooled preparations carry the disadvantage of higher donor exposure for the recipient and the risk of developing antibodies against HLA (human leukocyte antigens) or HPA (human platelet antigens).

On the other hand, single-donor preparations are used when HLA-compatible products are needed. HLA class I is expressed on the platelet, and if a recipient has antibodies against these HLA characteristics due to a previous transfusion or pregnancy, the transfused platelets can be targeted and destroyed by the recipient's antibodies. The spleen and the liver are mainly involved in the destruction of platelets.

For more detailed information about the supply of platelet concentrates, refer to the chapter "Treatment with TKS."

Platelet concentrate specifications include:

• The requirement for it to be leucocyte-depleted.
• Containing no more than 10^6 leucocytes.
• Having a minimum cell count of at least 2 x 10^11.

A platelet concentrate typically contains approximately 30 ml of residual plasma, while the platelets themselves are suspended in a nutrient solution (PAS). 

Pathogen-inactivated platelet concentrates can be stored at 22-26°C for seven days under constant agitation (horizontal shakers). All platelet concentrates, not only the pathogen-inactivated ones, must be kept in horizontal shakers.

For years, an increasing number of blood banks have been implementing pathogen inactivation to address the "new emerging pathogens." As far as I am aware, only the blood bank in Linz continues to use platelet concentrates without pathogen inactivation.

Last update on 01.07.2024.