"He was examined but not admitted," prisons service spokeswoman Sivan Weizman told AFP, without elaborating.
Sarsak, an administrative detainee from Gaza, is demanding to be recognised as a prisoner of war.
Administrative detention is a procedure dating back to the pre-1948 British Mandate under which military courts can hold suspects without charge for periods of up to six months, which can be renewed indefinitely.
Sarsak began refusing food on March 23, and went for 53 days without eating until a deal ending a mass prisoner hunger strike was signed on May 14.
He resumed his strike a day later and Weizman has said that he has been fasting "on and off" since then.
Also currently on hunger strike is Akram Rikhawi, who has served two thirds of a nine-year sentence and is seeking parole.
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