These therapies could be used to treat sickle cell anemia, leukemia and other blood disorders. If markers lead to the discovery of additional types of stem cells, new treatments for many forms of cancer may become available in the not-too-distant future.

Amy Wavers, a stem cell specialist at Harvard's Joslin Diabetes Center, told Discovery News that she welcomed the barcode method for identifying blood stem cells because it is "simple and broadly applicable."

She said, "The new method allows us to look at stem cells in their native environment, which is in actual tissue cells. It is also a big advance because we now have a greater chance of obtaining more pure stem cell grafts (samples)."

Wavers explained that patients undergoing bone marrow transplants currently receive a mixture of cells, some of which may or may not be stem cells. The easier identification method will tell doctors if enough stem cells are present to warrant the transplant.

Morrison said these identifications could be a life or death matter, as for cancer patients who have blood removed and frozen before chemotherapy. Chemo kills cancer cells but also can damage healthy blood cells in the process. When patients receive their blood back after chemotherapy, sometimes doctors miss detecting cancer cells within the blood and the person is subjected to cancer again.

"It is really important that we purify the frozen stored blood, and the new method will dramatically enhance our ability to do this," he said.