A person with Type O blood might be able to donate a kidney to a person with Type B blood, as long as the rest of the matching is acceptable. Your aunt would have to go to a transplant unit and determine is she is a candidate to receive a kidney. If she is then placed on the list, then you can be evaluated to see if you are a match. I am unaware of costs in this circumstance. The transplant center that evaluates your aunt might be able to advise you about costs and the procedures you and your aunt may have to go through.
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