Why does the red cross blood bank accept donations no more than once every three months?

nice...ask yahoo about your math test lmao

you shouldnt give more than that, it takes your body time to repair after giving blood.
I'm pretty sure it's because your body needs time to replenish the lost blood volume and of course the red and white blood cells. But as far as I know, it's 56 days, not 3 months, that you have to wait.

I don't think the Red Cross is the agency handling blood donations. Yes, you see a "red cross" at blood centers, but mostly these are not-for-profit companies (they make profit, but are required to put the profit into the company. And yes, they probably do that in the form of paying the executives better and better whenever they count the profits.) An example is the Long Island Blood Services. I worked for them for about 6 months, calling donors to solicit blood donations.

We were trained that people could donate after waiting 56 days (not three months) after their last donation. That was for whole blood. For plateletpheresis, people could donate after 28 days since their last platelet donation.

Plateletpheresis involves having your blood drawn, platelets removed with a centrifuge, and the blood is returned to you with saline added to preserve the volume. It used to be done with a needle in each arm, and would take about 1.5 hours! It's a long time to wait with a needle in your arms, unable to move or even scratch your nose. I understand that nowadays, somehow they use a needle in only one arm, that handles both the drawing of the blood and the returning of it!

I'm no longer allowed to give blood because of a policy they enacted for anyone who has spent more than 3 months in a country that has "mad cow disease." I studied in England, so I'm deferred. Grrr. I used to like helping people by donating my blood.
that's how long your body takes to replace the blood you've donated
It takes your body about 128 days to recycle all of your blood. When you give blood, you increase the burden on your body to manufacture red blood cells to handle normal regeneration requirements and to make up for the loss as well.
Dave Saunders, NC, DNEH
Certified Nutritional Educator and Wellness Coach, ANA
Member of the American International Association of Nutritional Education (AIANE)