Platelets are collected for transfusion either by centrifugation of plasma from a unit of whole blood or by which method?

Plateletpheresis is the correct method for collecting platelets for transfusion, as it is a specialized procedure specifically designed to concentrate and collect platelets from a donor's blood. During plateletpheresis, blood is drawn from a donor, and various components are separated using a centrifuge. In this process, platelets are isolated while the other components of the blood (like red blood cells and plasma) are returned to the donor.

This technique allows for the collection of a higher yield of platelets in one session than could be collected through other methods, such as manual extraction or direct aspiration. Additionally, plateletpheresis can be performed using automated machines that monitor and control the process, ensuring safety and efficiency.

In contrast, methods like plasma exchange or manual extraction do not specifically cater to the selective collection of platelets. Plasma exchange primarily focuses on the removal and replacement of plasma rather than isolating platelets, while manual extraction involves physically retrieving platelets through various means, which is less effective and more labor-intensive than using apheresis technology. Thus, plateletpheresis stands out as the most appropriate and effective approach for the collection of platelets intended for transfusion.