Those who have formed their own sects or denominations based on the teaching(s) of this or that person have a tendency to take a verse or two out of the Scriptures and twist it into a doctrine.
Some groups (Christian Science, 7th Day Adventists come to mind) take the Old Testament prohibition against eating blood to mean that use of blood or blood products in medicine are also prohibited. For some reason they disregard that in the book of Acts the dietary regulations were repealed.
