FEB. 27–ATLANTA, Ga.–The Food and Drug Administration says tests conducted so far indicate white particles first detected last month in a batches of blood throughout the southwest pose no health or safety risk.

“Although the cause of the particulate matter is not yet fully explained, there is no evidence it poses a threat to blood safety at this time,” according to the FDA.

The FDA began investigating in January after it received reports of white particulate matter in a batch of blood in bags manufactured by Baxter Healthcare Corp. in Georgia. Later it was determined at least 120 units of blood distributed to Georgia and several surrounding states, including Florida and Tennessee, contained the particles.

Baxter has said its investigation indicated the white particles were clumps of normal blood cells or proteins, a finding with which the FDA now agrees.

“Findings to date indicate that the particles are composed of normal blood substances and that rates of adverse reactions to transfusions have not increased since the blood particles have been observed,” the agency said.

In addition, “all analyses to date of possible infectious agents, chemical contaminants, or blood bag defects have found no abnormalities that indicate a public health risk,” the FDA said.

The agency said normal components of blood sometimes can form into clumps because of certain physical conditions of blood handling. The agency said one hypothesis it is investigating is that the particles could be normal components of blood called platelets, which are known to “sometimes form visible particulates.”

The FDA, along with other health agencies and blood banks, will continue to conduct studies on the safety and the cause of the particles.