This is the big question really.  The following information if reproduced from the Anthony Nolan Trust's booklet "Commit to a Life Saving Procedure Now".

If You Are A Match

If your tissue type is found to be a complete match (there may be occasions where you were found to be a partial match), you offer immeasurable hope to that patient, often at a time when desperation and fear are the overriding emotions faced.  Once identified as a tissue matched compatible donor - and prior to the donation - you will have a medical examination by an independent physician to confirm your fitness to proceed.  Further blood samples will be taken to assess your health and ensure that no infection could be passed from you to the patient.  The Anthony Nolan Trust not only helps patients in the UK, but also around the world. All blood stem cell donations from Anthony Nolan volunteers, however, take place at one of the specialised centres in London and are hand carried by a personal courier to the patient's transplant centre. The Anthony Nolan Trust makes all the arrangements for the donor and covers any financial loss incurred by our donors as a result of having donated blood stem cells (subject to prior agreement). A family member or friend is also able to accompany you to London.  In compliance with international agreement, strict anonymity is maintained between donor and patient.  After the donation you  are at liberty to decide whether to remain on the Register.  There is no reason on physical grounds why a healthy person should not donate on more than one occasion.

Donation Options

Bone Marrow Extraction

Blood stem cells can be collected by bone marrow extraction or taken from the peripheral blood. Ideally all volunteers should be willing to donate by either method.  However, the final choice of donation method would be yours, with guidance provided to help you reach the most appropriate decision.  Bone Marrow Donation Bone marrow donation requires a two-night stay at a specialist hospital in London to for a medical procedure called a harvest.  Under general anaesthetic, blood stem cells are extracted from the pelvic bones by sterile needle and syringe. No surgical incision is required, and the blood stem cells replace themselves within 21 days. You may feel some short-term post-operative tenderness and discomfort in your lower back and tiredness is inevitable during recovery.  It is, therefore, advisable to plan to recuperate for approximately one week before returning to work or other normal duties.  The most serious complication for the donor could be reaction to the anaesthetic, but the risk is extremely low and certainly no greater than undergoing any minor operation. 

Peripheral Blood Stem Cell (PBSC) Donation

Blood stem cells are also found in the circulating blood stream (peripheral blood) as well as the marrow, but in much smaller numbers.  A growth factor known as granulocyte-colony stimulating factor (G-CSF,which occurs naturally in the body and regulates production of certain white cells (neutrophils), is injected for five days prior to the collection.  This temporarily boosts neutrophil production and encourages movement from the bone marrow where the cells are made, out into the peripheral (circulating) blood.

The cells are then collected via a sustained needle on a blood cell separator machine, in a process known as apheresis. One or two collections on consecutive days, each lasting approximately 4-5 hours may be required, but overnight hospitalisation is not usually necessary and no general anaesthetic. The effects of the G-CSF may include bone pain and flu-like symptoms during the 5 day period the drug is being administered but which resolve 1-2 days after the last dose of the drug. During the collection the donor may experience discomfort at the sites of the needle insertion and a temporary tingling sensation in the body from the anticoagulant used to keep the cells from clotting. No extended recuperation period should, therefore, be necessary, although you are likely to feel tired for a short time afterwards.