Platelets play a critical role in the blood clotting process. The number of platelets in the blood is referred to as platelet count and normally ranges from 150,000 to 450,000 per one millionth of a liter of blood.
A platelet count with less than 150,000 per microliter of blood is termed as thrombocytopenia while a platelet count greater than 450,000 is referred to as thrombocytosis.
Low platelet count in the blood may result from different medical or hereditary factors. When thrombocytopenia develops, where the number of platelets in the blood is considerably lower than normal levels, it increases the risk of bleeding as platelets are responsible for blood coagulation. The medical condition can lead to nosebleeds, heavier periods, bleeding gums, bruising, or more serious blood disorders.
In some patients with a large drop in platelet counts, a commonly available treatment option is called platelet transfusion which is performed when the drop reached a certain level. To prevent spontaneous bleeding, the doctor will likely recommend platelet transfusion collected from viable donors. A consent will be necessary when the patient has to undergo platelet transfusion procedure.
1. Importance of platelet donation
The donation of platelets has proven to be lifesaving especially in patients with thrombocytopenia who experience bleeding episodes. It is with platelet transfusion that the control of excessive bleeding in patients can be made possible.
Patients with massive blood loss from trauma or surgery are transfused with red blood cells (resulting in partial replacement of the blood volume), fresh frozen plasma, and random donor platelet units. Platelet donation plays an important role in assisting the recipient’s body replace lost platelets in the bloodstream.
Prophylactic platelet donors allows for transfusion that prevents spontaneous bleeding in afebrile patients with platelet counts that are about 10,000/microlitre; such us conditions resulting from bone marrow suppression.
The donation can be helpful in saving lives of patients with platelet consumption disorders such as heparin-induced thrombocytopenia (HIT), immune thrombocytopenia (ITP), thrombotic thrombocytopenic purpura (TTP), liver disease, disseminated intravascular coagulation (DIC), and those with platelet function disorders. However, it has also been associated with increased risk of thrombosis.
- Darrell J. Triulzi, Susan F. Assmann, Ronald G. Strauss, P. M. Ness, John R. Hess, Richard M. Kaufman, Suzanne Granger, & Sherrill J. Slichter (2012). The impact of platelet transfusion characteristics on posttransfusion platelet increments and clinical bleeding in patients with hypoproliferative thrombocytopenia.
2. Need for platelet donation
People with leukemia, patients undergoing cytotoxic chemotherapy, and hematopoietic cell transplant (HCT) cannot produce their own platelets due to suppressed bone marrow. Prophylactic transfusion is used in these settings which can only be possible with platelet donation.
Platelets are also required when preparing for an invasive procedure, especially when the level of thrombocytopenia is severe and the risk of bleeding is deemed high, in a thrombocytopenic patient.
3. Method of collecting the platelets
Platelets are collected through a process called Plateletpheresis, also thrombocytapheresis or thrombapheresis. This is a process of collecting thrombocytes which is performed using devices in blood donation that separates the platelets from the other components of the blood withdrawn from the donor.
The process is also applicable therapeutically in treating disorders that result in high platelet counts such as thrombocytosis. When donating platelets, a small volume of the donor’s blood, about 1/4 pint, is drawn from the arm and passed through the cell-separating machine. The machine collectively segregate the platelets and safely returns the remaining blood components to the donor. The retuning is accompanied with some saline.
4. Quantity of platelets to donate
A full platelet donation session provides enough platelets for a full therapeutic dose of one patient in need. Some platelet donations provide enough platelets for two, three, or even four therapeutic doses.
However, it takes four to six whole blood donations to yield a single platelet therapeutic dose. Individuals in need of platelets are usually patients undergoing chemotherapy or sometimes organ transplant and therefore, have weakened immune systems.
When a platelet dose is sourced from a single donor, it reduces the patient’s exposure to possible multiple donors and is preferred by most doctors.
- Elvedin Landzo, Alma Sofo-Hafizovic, & Vesna Cetkovic-Basic (2013). Initial Values of Donor Hematocrit and Efficiency of Plateletpheresis.
- Qing Feng, Faming Zhu, Chunyan Li, Beijie Guo, Jun Ye, & Jiangtian Chen (2019). Effect of Frequency of Platelet Apheresis on Coagulation Function in Donors: A Prospective Cohort Study.
5. Individuals eligible to donate platelets
Anyone can become a platelet donor if they are generally in good health and aged 17 to 65, for those who had never donated before. For those who are above 65, they can only donate platelets if they had donated prior.
Donation for those who are over 70 years is only possible if they had given a full donation once or several times in the previous 2 years. Platelets must not be donated by individuals who have taken aspirin, aspirin-containing medications, piroxicam or nonsteroidal anti-inflammatory drugs, 48 hours before donating platelets.
6. Important assessments and tests before donation of platelets
Before donation, a small sample of blood is taken from the donor to determine if they have sufficient platelet count. Assessment of the sample can take about 6-8 weeks, during which the blood group of the donor is determined. Gender, height, and weight are considered to see if they have large enough blood volume to provide for donation of platelets.
7. How is platelet donation done
A cuff is usually placed around the donor’s arm, the skin is cleansed and a local anesthetic is injected before a needle for the process is inserted. Blood samples are eventually taken for testing just as in blood donations. Height, weight, and blood type assessments are carried out to determine suitability.
8. How to ensure safety of the donated platelets
Platelets can only be kept for 7 days. Proper handling is essential to ensure safety of the entire process which should be implemented starting from the time when the donor is selected to the point where it is received by the recipient. Each donation is supervised throughout the procedure by trained medical staffs.
Donation equipment that can be observed during the procedure include the needle, tubing, and collection bags that have undergone sterilization and immediately discarded after each donation session. Therefore, it is almost impossible for any disease to be contracted from the process.
- Josefsson E.C., Hartwig J.H., & Hoffmeister K.M. (2007). Platelet Storage Temperature – How Low Can We Go?
- Scott Murphy & Frank H. Gardner (1971). Platelet storage at 22°C; metabolic, morphologic, and functional studies.
- Cécile Aubron, Andrew W. J. Flint, Yves Ozier, & Zoe McQuilten (2018). Platelet storage duration and its clinical and transfusion outcomes: a systematic review.
9. What to do after the donation
After a person has donated platelets, it is advised that the individual resumes to normal activities. However, some other restrictions may apply to varied blood donations. In cases of any unusual experience like suffering from discomfort after the platelet donation process, it is advised that the donor seeks immediate medical attention from a doctor.
10. Challenges and risks of blood donation
The equipment involved is expensive. Not all people are willing to donate platelets, and some of them even withdraw during the procedure. The possible risks when donating platelets can be classified into three categories: Those that has something to do with blood pressure changes, challenges with vein access, and the effects of the anticoagulant on the calcium level of the donor.
Blood pressure changes may cause nausea, dizziness, and fatigue. Venous access problems can result in bruising (hematoma). And also, since anticoagulants work by binding to the calcium substance in the blood, the process of platelet donation can lead to a drop in calcium levels in the donor’s blood. This can result to additional problems such as nerve irritation, fainting, and even short-duration tetany.
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