Platelets (thrombocytes) are small cell fragments that play a fundamental role in hemostasis, the body’s natural process for stopping bleeding. They rush to a damaged blood vessel, adhere to the site, and clump together to form a temporary plug that initiates clotting. Because platelets have a very short shelf life (typically five to seven days), a constant supply is necessary. Transfusions are frequently needed for patients undergoing cancer treatment, as chemotherapy and radiation often suppress the bone marrow’s ability to produce platelets. Platelets are also administered to trauma victims, those undergoing major surgery, or patients with blood disorders to prevent hemorrhage.
Donor Eligibility and Preparation
To begin the donation process, individuals must meet specific health and eligibility criteria. Donors must be in good health, be at least 17 years old, and weigh a minimum of 110 pounds. Initial screening includes a confidential health history review, a check of vital signs (such as blood pressure and pulse), and a blood sample to confirm adequate hemoglobin and platelet levels.
The most specific requirement involves avoiding medications that affect platelet function. Aspirin and aspirin-containing products must be avoided for at least 48 hours prior to the appointment because they permanently impair clotting. Some centers also require avoiding non-steroidal anti-inflammatory drugs (NSAIDs), like ibuprofen, for 24 to 48 hours.
Preparation 24 to 48 hours before the donation is important for a smooth experience. Donors should increase fluid intake, as hydration helps maintain blood volume and makes vein access easier. Eating a nutritious, non-fatty meal that includes calcium is recommended because the anticoagulant used binds to calcium, and a slight drop in the donor’s calcium level can sometimes lead to minor side effects like tingling.
The Platelet Apheresis Procedure
Platelet donation uses apheresis, a specialized process that collects a concentrated unit of platelets while returning the remaining blood components to the donor. The process begins with inserting a sterile needle, usually into an arm vein, which draws whole blood into an automated apheresis machine. Inside the machine, the blood is spun in a centrifuge, separating the components based on density: red cells, white cells, plasma, and platelets.
The machine isolates and collects only the platelets into a separate bag, yielding the equivalent of several units from a single donor. The remaining components, including red blood cells and plasma, are then returned to the donor, often mixed with a saline solution. This continuous cycling is repeated multiple times throughout the donation period.
While some procedures require a needle in each arm (one for drawing and one for returning components), many modern centers use a single-needle access for the entire apheresis process. The donor is seated for the duration, which is longer than a whole blood donation, typically lasting 90 to 120 minutes. Donors are encouraged to relax, read, or watch television during this extended period.
Post-Donation Care and Frequency
Following the procedure, donors are encouraged to remain in the center briefly to rest and have refreshments. Replenishing fluids is important; drinking non-caffeinated beverages helps restore the plasma volume removed during the process. The body replaces the donated platelets within 48 hours.
To prevent bruising, a pressure dressing is applied to the access site and should be kept on for about 30 minutes, with the plaster remaining for several hours. Donors should avoid strenuous activity and heavy lifting with the access arm for the remainder of the day to ensure the puncture site heals properly. Most individuals feel well enough to resume their daily routine after leaving the center.
A key advantage of apheresis is the frequency of donation compared to whole blood. Because the red blood cells are returned to the donor, the body’s recovery time is shorter. Platelet donors can safely give platelets as often as every seven days, though many centers recommend an every-other-week schedule. This allows donation up to 24 times within a 12-month period, providing a continuous supply for patients in need.