The refusal of Israel's equivalent of the Red Cross to accept blood from an Ethiopian Jewish lawmaker sparked demands on Wednesday for a review of guidelines seen as deeply discriminatory.
The rejection of the blood from Pnina Tamano-Shata by an official of Magen David Adom came at a donor drive outside parliament and was caught on video footage which was widely aired by Israeli television channels.
"Under health ministry directives, we are unable to accept blood from donors of Ethiopian Jewish origin," the health official is heard to say as he spurns the donation.
Ministry guidelines do not in fact bar donations from all of Israel's more than 120,000 Ethiopian Jews, only to those 80,000 among them who were born in Africa and migrated to Israel, most of them in two massive airlifts in 1984 and 1991.
The pretext long given is that it is a measure to prevent the AIDS virus getting into the blood bank and being spread through transfusions.
But critics say the blanket ban has no medical basis and masks persistent racism among other Israeli Jews towards the black Ethiopian minority.
Tamano-Shata is a member of parliament for the centrist Yesh Atid party, part of Israel's governing coalition.
Prime Minister Benjamin Netanyahu rang her to express his "admiration" for her offer to give blood and to promise a review of the ministry guidelines.
Tamano-Shata herself hit out at an "affront to an entire community on the basis of the colour of their skin".
"I'm 32, I arrived in Israel at the age of three, did my military service and have two children. There's no reason to treat me in this way," she told Channel 10 television.
She recalled that 16 years ago, the revelation that health authorities were secretly throwing away blood donations from Ethiopian Jews had sparked a massive protest in Jerusalem.
"I myself took part in that demonstration but nothing has changed since then," she said.
Top Magen David Adom officials later agreed they could take Tamano-Shata's blood, but only to freeze it, not to put it into the national blood bank, the Ynet news website reported.