from ajwrb.org
Some Jehovah's Witnesses believe that a blood transfusion is a liquid tissue or organ transplant, not a meal, and hence does not violate the biblical admonition to "abstain from [eating] blood." The Watchtower Society attempts to deny these members, many of them born to JW parents, a free choice in their medical care by means of controls and sanctions - namely enforced shunning by JW family members and friends. They have been persecuted for their conscientious beliefs by their own religious organization which presents itself as a champion of human rights.
from wikipedia...
Some feel there are two inconsistencies in the current policy that groups such as "Associated Jehovah's Witnesses for Reform on Blood" are attempting to have addressed. They feel that accepting blood fractions does not adhere to the principle that blood be poured out. Furthermore, they also believe that if blood fractions are accepted then Jehovah’s Witnesses should also be allowed to donate blood.
When asked the question, can Jehovah's Witnesses accept blood fractions? The official answer is "We can not say. The Bible does not give details..." [31] Thus it is left to each member to make their own conscientious decision. This is because the Bible itself does not define the Greek word, "HAIMA" rendered blood. This would not pose an issue back in Bible times. However, today blood can be broken down into components, and now even further into smaller fractions. Are these tiny fractions "blood"and thus to be "abstained" or are they no longer "blood"? Witnesses will vary on how they decide and feel.
An essential point to keep in mind while trying to understand their view on blood is that the fluid blood per se is not the real issue. The real issue is respect and obedience for God’s personal property- blood. [32] [33] That the matter blood is not at stake, is seen in the fact that members are allowed to eat meat which will still have some blood left in it. As soon as blood is drained from an animal, the respect has been shown to God and then a person can eat the meat even though it will contain a small amount of blood.
It is also important to realize that an Israelites could give, or sell an animal which was not bled to a foreigner who was not bound by the same laws. [34] Thus a foreigner could eat blood (in the animal) whereas an Israelite could not. Jehovah’s Witnesses do not donate blood since they do not see how doing so shows the respect God asks for the substance. With the above in mind, some do not see any inconsistencies in the official blood policy. Others, however, see the above as cognitive dissonance.
If a person has previously been disfellowshipped for accepting a blood fraction that is now permissible they are not automatically reinstated, as the disfellowshipping is considered to be a result of showing disrespect for the leadership of the Organization as much as the issue of blood.
Just a couple of resources. Enjoy!