Apheresis is the technical term for seperating things from stuff, but usually used when talking about donating
platelets, the part of your
blood responsible for
clotting, or
plasma, which helps maintain
blood pressure and supplies
protein for clotting and immunity.
Platelet transfusions are needed by some normal surgeries, organ transplants, chemotherapy, radiation therapy, bone marrow transplants and an increasing number of new therapies and treatments. Plasma is needed for newborn babies, burn victims, people with leukemia and transplant therapy.
Unfortunately, platelets only have a 5 day shelf life, so fresh platelets are always in demand. Until modern blood separators were invented, the plasma or platelets from multiple whole blood donations were pooled together until enough was collected. Now the process is much simpler and faster. Whole blood is taken out of a vein in your arm, travels through sterile tubing into a very intricate and complex blood cell separator, where a centrifuge is used to separate the desired cells (either plasma or platelets) from the rest of the blood. The blood is then sent back to your body through more sterile tubing and back into a vein, usually in the other arm. Some apheresis machines send the blood back through the same needle. The amazing part of the process is the whole blood never leaves the sterile tubing. Platelet apheresis takes about 2 hours and plasma apheresis takes about 20 minutes longer than a whole blood donation. Your body starts replenishing its supply of platelets or plasma right away, so you can go back for another donation after 48 hours.
From my own multiple experiences with platelet apheresis, the process is simple but is a bit time consuming. After arriving at the blood donor center, you go through the usual round of questions and fingersticks, as in the excellent writeups in giving blood. Once you're reclining in one of their extra-comfortable donor chairs, the area around the veins (usually the inside of the elbows) are cleaned and you get hooked up - out one arm and back in the other. The blood cell separator is put into motion and you've got about the next hour and a half to sit back and chill out and watch a movie. Reading isn't really an option as you've got a needle in each arm which greatly restricts arm movement. Even though most of the blood in your body is processed, only about 4% of your platelets are extracted, roughly a teaspoon. The platelets are collected in a bag, which slowly fills with a pale yellowish fluid. When the apheresis is complete, the blood cell separator backflushes the tubing with saline, so the overall volume of fluid in your circulatory system hasn't changed. This means your blood pressure hasn't changed, so the likelyhood you might pass out is damn near zero (unless you're scared of needles). Due to this, you can hop right up and head out as soon as you're bandaged.
Platelet apheresis has been a very rewarding experience for me, and i try to do it regularly. The Red Cross has put me on their call list for whenever their platelet supply gets low, as i donate often and easily pass all their requirements for donation.
If you're interested in plasma or platelet donation, please call 1.800.GIVELIFE or visit http://www.redcross.org/services/biomed/blood/learn/apheresis.html and please donate if you can. You'll help save lives by giving to others what you have an abundance of and will replace in a matter of hours.