Perhaps controversial as to its authentication; nevertheless, worth considering:
"When faced with mounting opposition, Fred Franz eased the Society's position on blood regarding the following [bold added]: (1) Serum injections such as diphtheria toxin antitoxin and gamma globulin blood fractions were permitted. (2) There was no need to drain blood from fish (except when "a person sees an accumulation of blood"), only land animals. (3) While a Witness could not personally use fertilizer using blood, he could use it when employed by a non-witness. This and similar situations were made matters of conscience. (4) Over the years, the Watch Tower Society had taken the position of prohibiting the use of blood fractions in the treatment of hemophiliacs. But long before officially leaving this stringent position, if one were to call the headquarters they would be told that such treatment was permissible. Years later, in the June 15, 1978 WATCHTOWER, the "oracle" decided the pressure was getting too severe, so he withdrew his position altogether, and permitted both hemophiliac preparations Factor VIII and IX. How many hemophiliacs died in the interim, further sacrifices on the altar of man-made Watch Tower dogma?"
THE FOUR PRESIDENTS, E. C. Gruss, Ed. p. 77.
https://www.jehovahs-witness.com/topic/126825/persecution-wanes-banning-blood-garners-publicity