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From one pint of blood comes bevy of life-saving uses

BY KAREN SCHMIDT

When you donate at Stanford Blood Center, you likely imagine that your red blood cells could save the life of an accident victim at Stanford Hospital or a newborn at Lucile Packard Children's Hospital. That might be true, but your imagination should stretch much further because the blood center makes dozens of blood-derived products and sends them far and wide.

Although most blood banks make use of red blood cells and platelets and discard white blood cells and serum, Stanford lets almost nothing go to waste. "We are the ultimate recycler," said Vince Yalon, the center's administrator.

Imagine a woman who donates a pint of blood at the new blood center facility on Hillview Avenue. Where does it wind up?

  • Her red blood cells and platelets could go to a patient at O'Connor Hospital in San Jose undergoing emergency gastrointestinal surgery.
  • Her plasma—the blood's fluid suspension—might be sold and sent overseas to a European biotech company that extracts and purifies clotting proteins for treating hemophiliacs.
  • A tiny tube of her whole blood likely would end up in the blood center's histocompatibility laboratory, where researchers characterize certain markers on the coats of her cells and then add the information to a panel that doctors use as a guide when trying to evaluate the compatibility of donor organs.
  • The woman's white blood cells could be given to one of many grateful research groups. Edgar Engleman, MD, the center's medical director, for instance, needs dendritic cells—rare white blood cells that serve as sentinels and alert the body to viruses and tumor cells—as he researches ways to marshal these cells to fight cancer.
  • And if the woman's blood tested positive for hepatitis C, it would not be fit for transfusions, but it would be of great use to Steven Foung, MD, director of the center's viral immunology lab and professor of pathology. He needs white blood cells from such donors to help study how the virus that causes the disease binds to these cells, and, thus, be able to one day develop a vaccine.
  • With the new Hillview donor site open, the blood center expects to expand its ability to churn out this wide variety of valuable products. Each day the center's staff of 260 workers takes pints of blood collected from volunteer donors, tests them for pathogens and other characteristics, and separates the living liquid into samples of red blood cells, platelets, white blood cells and serum. Finally, they process, package, carefully label and sort these into as many as 75 specialized products.

    Demand is greatest for red blood cells, the component that carries oxygen throughout the body. The blood center's daily collection sits in a row of specialized refrigerators on shelves marked with blood types O, A, B and AB, followed by an Rh positive or negative sign.

    Each red-brown packet is pasted with a label containing strings of letter codes. These reveal the results of tests, some for genetic markers such as the sickle cell trait and others for antigens, substances that might cause a "transfusion reaction" in certain recipients. The codes tell physicians whether a blood sample is a good match for a particular patient.

    Indeed, Stanford prides itself on such "boutique" blood products created using cutting-edge technology. This tailored approach to blood banking evolved because of the blood center's mission to serve the specific needs of patients and researchers at Stanford Hospital and Lucile Packard Children's Hospital. "We offer a larger array of blood products because Stanford patients have unusual needs, tend to be sicker, and have more complications," said Engleman, who is also a professor of pathology and of medicine.

    The center, for example, provides premature infants with special blood-derived products that come in tiny container units and receive extra safety testing. To protect preemies (and others with weakened immunity), the center runs 14 tests to screen donor blood for pathogens, including cytomegalovirus, a common and normally harmless virus that could kill these particularly vulnerable patients.

    Because the staff does extensive testing and labeling in advance, the blood center can create stocks of different products and send them out to hospitals ready for use. "Then you have the blood waiting for the patient, rather than the patient waiting for the blood," said Yalon. That gives hospital workers a jump on emergencies, such as when a patient who received a bone marrow transplant quickly needs compatible platelets to boost his blood clotting.

    With demand for its specialty products growing at about 15 percent annually, the blood center hopes to increase its annual collections of blood components from 100,000 to 120,000. The new Hillview donor site is expected to help meet that challenge.


    Karen Schmidt is a freelance science writer who lives in the Santa Cruz area.