A new technique will test the theory that too much calcium is the cause of painful crises in patients with sickle-cell disease.

"The problem is not how much calcium intake you have, but what your body does with the calcium," says Dr. Robert Schlegel of Pennsylvania State University.

The disease causes red blood cells, normally round, to become crescent-shaped. When these misshapen cells attach to the walls of small blood vessels, they cause a painful episode that often requires hospitalization. Recently discovered sacs of calcium, or vesicles, in the cells may explain why they become "sticky."

Using a new staining technique that allows them to examine many cells at a time, Schlegel and several colleagues hope to "look at the sickle cells that stick and see if they happen to have more vesicles, or if they have vesicles that are broken so that the calcium has been released."

The scientists reported on their research recently in the Journal of Cellular Physiology.

The research could provide insight into why sickle cells process calcium differently than normal cells. But consuming less calcium would not be a treatment, the scientists say, because "the problem is the cells and not the level of calcium in the blood."

More than 50,000 Americans, predominantly blacks, have sickle cell disease, and an estimated 8 percent of American blacks carry the sickle cell gene.