Caroline Gramas spent her summer donating plasma at Sera Tec Biologicals Inc. Why did Gramas (senior-hotel, restaurant and institutional management) donate? "For the money."

Sera Tec, located at rear 120 S. Allen St., pays about 800 people a week to donate their plasma -- the fluid part of the blood that remains after the red blood cells are removed. The plasma is then used to make medical products, said Carl Lucas, vice president of regulatory affairs at Sera Tec.

Normally, donors receive $12 for their plasma, said Bonnie Zimmerman, the manager of the State College center. But because people can donate twice within seven days, donors receive $15 for their second visit in a calendar week, Zimmerman said. What product the plasma is used for, Lucas said, may also change the payment.

For example, people who are recovering from mononucleosis are encouraged by Sera Tec to donate plasma and are offered $50 to $70, Lucas said. The high price reflects the need for this product -- the center gathers plasma containing mononucleosis antibodies to make kits that doctors use to test people for mono. And because the mononucleosis antibody disappears soon after the patient recovers, donors recovering from mono receive more for their plasma, he added.

Between 90 and 95 percent of plasma collected by the State College Sera Tec center is converted into an anti-hemophilic factor, Lucas said. The factor, known as Factor 8, allows normal clotting in healthy blood. Some people (called hemophiliacs) do not have Factor 8 in their blood and need the anti-hemophilic factor supplement.

At 27 centers around the country, plasma is collected and distributed to pharmaceutical companies, Lucas said. These companies manufacture medical products, such as Factor 8.

Lucas said not just anyone can give plasma. Prospective Sera Tec donors are thoroughly examined to make sure they are healthy, Zimmerman said.

"We have a doctor on staff at all times," she said, adding that all of Sera-Tec's workers are trained.

Before each donation, Zimmerman said, Sera Tec workers monitor the donor's vital signs -- blood pressure, temperature and blood type. Each donor is assigned a permanent identification number, she said, and all files remain confidential.

Once through the preliminary screening process, the donor is led downstairs to the donation room. A donor normally gives 600-650 milliliters of plasma, depending on how many red blood cells he or she has.

Sera Tec uses two methods to extract plasma: the automated system and the manual method, Zimmerman said. If an automated system -- a machine that separates plasma from the blood and then returns the blood cells to the body -- is used, the donating process takes about 30 to 35 minutes.

But with the manual system, she said, the plasma must be removed from the blood in a separate machine, so the donor spends more time waiting for the return of the red blood cells.

"There is no way of contracting anything from donating plasma," Zimmerman said. "Everything is pre-sterilized and is discarded after every donation."

"The body will put back that plasma in four to eight hours," Lucas agreed. But the red blood cells are returned to the body to prevent anemia.

Jill Falkenstein, donor room supervisor, said most of the donors do return to donate again.

"Once they realize it's not scary at all they come back," Falkenstein said.