Can I get paralyzed?

NO, NO, and NO! , please help to break these urban legends: The Great Wall of China can't be viewed from the moon with the naked eye, and Bone Marrow is NOT Spinal Cord.
It's a common misconception, it's plain wrong, and sadly it is turning many would be donors away from registration.
For the registration, only 5ml of blood is taken from your arm.
For donation (for which there is only a chance in a million that this will even happen) it would be taken from your hip bone, or more and more often from your blood directly. See the article below "How is bone marrow collected? Will the bone marrow be collected from the spine or taking a chunk of my bone?"

What is bone marrow?

Bone marrow is a thick, blood-like tissue found inside the cavities of the body's hollow bone. It is responsible for the formation of stem cells from which blood cells (red, white, and platelets) are made. Bone marrow is a tissue completely different from spinal fluid, spinal cord, or nervous system.

Will I have to donate right away?

No – First step is only a registration. You will only be called if there is a match with a sick patient, and chances for compatibility are - unfortunately - extremely slim.
Is it like blood donation? 
A blood test will allow knowing your tissue markers that make up the HLA system, a very complex hereditary system, which is not the same as the blood groups (A, B, O and Rh) used for blood transfusion purposes. So criteria for donating blood or joining the Marrow Registry are different. In the U.S., they use oral swabs to collect your DNA cells for Bone Marrow registration.

Why me? 

It’s mathematical, the more people register, and the more chances there are to find a compatible donor. Most blood cancers are treatable diseases but there just aren't enough people in the registry to save the largest majority of them or at least give them a fighting chance.

Is my blood type important?

The most important aspect is the HLA matching. A 10/10 or at least 6/6 match is considered optimal. Once the best HLA match is identified then they will look into blood group including ABO, Rh compatibility, CMV status and so on. While blood group incompatability can pose challenges to management in the immediate post transplant period, incompatibility on this front alone is not grounds for rejection of a donor. Once the best HLA matches are identified these donors are then typically screened for other compatibility aspects to choose the best donor. In other words blood group compatibility is not of paramount importance in marrow transplants unlike in solid organ transplants.

How to become a Volunteer Bone Marrow Donor? 

For each country, the process can be slightly different, but the main steps are:
Registration of Volunteer donor and his/her HLA (« biological ID card ») - not to be confused with the blood type or Rh – into the local Bone Marrow Registry (medical questionnaire + brief medical interview + blood test). In Hong Kong, this registry is operated by the Red Cross, with a connection to the international Bone Marrow registry network. Then Physicians of patients awaiting a bone marrow donation submit preliminary search requests to the local registry.  If no match donor is identified, the search is then widening to other countries.

What are the steps to actually donate Bone Marrow? 

For each country, the process can be slightly different, but the main steps are: Once a match donor is identified, he/she is contacted to check availability and to proceed to further blood tests and medical tests.  On average, it takes 1-2 months since the volunteer donor is contacted till the actual donation occurs. Once further tests confirm « high/complete match », physicians and the volunteer donor meet to go over all possible questions the donor may have. The donor then gives his/her final donation agreement. Donation details and logistics are decided: Mode of donation, date scheduling taking into account the donor’s constraints and the patients’ health status, etc. 
There is a Hospitalization of the donor, collection of bone marrow, and transplantation into the patient within 12 to 36 hours. And post-donation follow-up of donor, possibly up till 1 year after. 

How is bone marrow collected? Will the bone marrow be collected from the spine or taking a chunk of my bone?

No – Bone marrow is not collected from the spine but from the hip bone, in the hip area. There are currently 2 methods to collect bone marrow cells.  In Hong Kong, it is the donor who decides which method he/she wishes to donate. (*)
A) Collection via blood stream (Peripheral Stem Cell Donation/ Apheresis): This method does not require the donor to undergo general anaesthesia.  A few days before, the donor is prescribed a medication that stimulates the stem cells production, and makes them migrate into the blood stream, where they will be collected.  One to two collections (each lasting about 4 hours) can be required.
B) Collection by hip bone puncture: This simple procedure takes place in an operating bloc under general anaesthesia. On average, the procedure requires 24 to 48 hours of hospitalization.

Does giving bone marrow hurt?

Some donors compare the feeling post-collection by hip bone puncture to a « big bruise », while some donors find that the preparation to collection via blood stream can give flu-like symptoms.   These symptoms, if they occur, can be treated by classic pain killers.  It is obvious that the donors’ medical safety is of great importance, before, during, and after the donation.

Will the donation affect the donor’s health? 

No – Generally the donation process collects less than 3% of the body’s total number of stem cells (HSC).  The donated cells will be replenished by the body within a short period of time.  There is thus no negative effect on the donor’s health, as the donation will not affect the donor’s health or immune status.

Can the donor change his/her mind?

All donors registered in the registry are on voluntary basis (*). They can have their names removed from the registry at any time, or may refuse to have further blood tests.  However, in view of the blood tests’ high costs and the potential disappointment caused to patients, it is important that prospective donors take in due consideration the ethics and moral implication of their registration beforehand.

Do I need to pay any fee for the registration and the donation? 

No – Donors (*) are not required to pay for any fee in relation to the blood tests, body check-ups, and hospitalisation for the donation. A medical leave certificate can be provided for their employer. In France, the law allows for the donor’s loss of revenue during hospitalisation to be financially compensated.

Can anyone donate bone marrow, without condition? 

No – For the donor’s safety (and that of the patient who will receive the donation), a brief medical questionnaire prior to registration will enable to identify any contraindication specific to bone marrow donation.  

If I am ineligible to give blood, can I still be eligible to be a bone marrow donor?

Yes - there are different criteria for donating blood vs. joining the Marrow Registry. Even though a person may be prohibited from donating blood, you might still be able to join the marrow registry. For instance in Hong Kong (*), diabetics on diet control with blood sugar level well controlled (between 3.5-6.6 mmol/L) will qualify.

What are the age criteria to register as volunteer bone marrow donor?

In Hong Kong (*), the age criteria is 18-60 years old.  In Singapore, the age limit is 17-49 years old.  In Taiwan and China, the age limit is 18-45 years old.  In fact, different country and registry has different policy, due to results of some medical research/study which showed that recipient tend to have better clinical outcome post transplant if donor tends to be of younger age.

Can I register to donate to one specific patient only?

No – By registering to the Bone Marrow Registry, the donor agrees to donate to any patient in need whom he/she proves to be a match.

Why do I really need to register, somebody else who registers can be the donor?

Most blood cancers are treatable diseases. There just aren't enough people in the registry to save the largest majority of them or at least give them a fighting chance. The patient that will not find a match will die. This is a community issue on an international scale. If someone you knew needed a transplant; you would want others to help them too. Currently the world donors’ registry is too low. USA, Germany and Brazil exceed 3 millions, Canada 320,000, France 199,000 and China including Hong Kong is 87,000. It is harder for some Ethnic Minorities and people of mixed ethnicities. 

If I want to encourage people living outside of Hong Kong to register as a volunteer donor, where can they go to register? Will their data be accessible from Hong Kong?

In most countries in the world, there is a bone marrow donor registry.  The information can be obtained from the country’s medical body (physician, clinic, hospital).  In France, an appointment needs to be made with one’s local “Etablissement du Sang Français”, as well as registration to the International Database. For other Asian countries, please refer to the next question. If that local registry is linked to the international bone marrow network, the information will be accessible from Hong Kong. The donor can also specifically request that his/her data be transferred to the HK Bone Marrow Registry (HKBMDR). 

Has this patient searched in other countries donor registries?

Yes, a worldwide search is currently on-going, but time is critical in this case.  It takes at least 2 months between the time a match donor is identified and contacted till the actual time of donation.  The further the donor is located from the patient, the longer time it will take.  In our friend's case, a bone marrow transplant is needed by September 2012, thus the urgency of our call and the ideal situation where a match donor is found in HK.

Which Bone Marrow Registry in Asia is linked to the international network?

Singapore BMDR, Japan BMDR, Taiwan Buddhist Tzu Chi SCC, China Marrow Donor Program (CMDP), Korea MDP, and Thailand Thai Stem Cell Donor Registry (TSCDR). There is no BM registration service in Macau so donors have to come to HK for registration. There is a Branch registry of CMDP in Guangzhou.  

Will I be asked to give my bone marrow more than once?

There are 2 particular situations where it is possible to donate bone marrow more than once: if the patient’s health status requires a 2nd transplantation, or if a family member of the donor needs a bone marrow transplantation (provided that high/complete match is established). But this is an extremely rare case.

Shouldn't I keep my bone marrow for my own family instead?

It sounds logical, but it doesn't compute with reality. It is true that there are many accounts of siblings donation, yet more than often compatibility is not found. Moreover, children are typically only 50% compatible with their own parents, while 80% is generally considered the bare minimum acceptable. A large proportion of saved patients were rescued thanks to the generosity of people with whom they were not even closely related. Beside, one can donate his/her bone marrow more than once should the need really arise.

What are the criteria that are exclusions to joining the registry?

Hong Kong Red Cross looks for donor in good health. Said some medical history just defer your registration such as Malaria. In their view, some examples for ineligible case:
Hypertension on medication
Diabetic on oral medication or insulin
Known Hepatitis B, Hepatitis C,  HTLV, HIV/AIDS, syphilis..
For virus HPVß can accept only if pap smear is negative + only grade I or grade 2. 
Known sexually transmitted disease or venereal disease
Epilepsy / convulsion on regular medication and required follow up
Drug abuse
Most autoimmune diseases/ immunological disease such as RA / SLE/……
Cardiovascular disease on treatment and follow up, except controlled arrhythmia
Sleep apnea 
Cystic fibrosis
Malaria attack (donation deferred for  3 years)
Meningitis with fit
Acute stroke
Many back and spine conditions
Bleeding disorders
Some pulmonary diseases such as emphysema
Most cancers or history of cancers, even after being cured or healed
Serious kidney disease or kidney removal
Tuberculosis in the previous year; 
Chronic lyme disease.

(*) Applicable for Hong Kong. Please consult local legislations for any other country/ territory.
Sources: Hong Kong Bone Marrow Registry  & www.dondemoelleosseuse.fr  
Information in Canada (French/English) about stem cells