Close to half a million dollars worth of donated blood is at the heart of a lawsuit between Oklahoma Blood Institute and a Minneapolis-based blood broker.

But it’s the details revealed in court filings and interviews about the high-dollar market for human blood and blood products that may come as a shock to donors, who give away the valuable product for free.

Donors often believe their blood is given to local hospitals, and all donations stay in the community — neither of which is true. A pint of blood in America sells to hospitals for $180 to $300, depending on the market, and expired blood often is sold to research laboratories, said Ben Bowman, chief executive of General Blood, the blood broker engaged in a legal tussle with Oklahoma City-based OBI.