"For example, during certain surgical procedures, some blood may be diverted from the body in a process called hemodilution. The blood remaining in the patient is diluted. Later, his blood in the external circuit is directed back into him, thus bringing his blood count closer to normal. Similarly, blood that flows into a wound may be captured and filtered so that the red cells can be returned to the patient; this is called cell salvage. In a different process, blood may be directed to a machine that temporarily carries on a function normally handled by body organs (for example, the heart, lungs, or kidneys). The blood from the machine is then returned to the patient. In other procedures, blood is diverted to a separator (centrifuge) so that damaging or defective portions of it can be eliminated. Or the goal may be to isolate some of a blood component and apply that elsewhere on the body. There are also tests in which a quantity of blood is withdrawn in order to tag it or to mix it with medicine, whereupon it is put back into the patient.
The details may vary, and new procedures, treatments, and tests will certainly be developed. It is not our place to analyze each variation and render a decision. A Christian must decide for himself how his own blood will be handled in the course of a surgical procedure, medical test, or current therapy.
Ahead of time, he should obtain from the doctor or technician the facts about what might be done with his blood during the procedure. Then he must decide according to what his conscience permits."