Researchers Identify Contaminant in Tainted Heparin

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However, Woodcock added, "it is very important that we all be confident that we understand the link [between the contaminant and reported illnesses], to ensure that the testing that FDA and others have put in place will prevent further adverse events."

U.S. officials also announced Monday that contaminated heparin products have now been found in at least 10 countries, in addition to the United States. The officials also said contaminated lots of the blood thinner have been traced to 12 different Chinese companies that were somehow involved in heparin manufacture.

Woodcock's announcement seemed to conflict with statements made earlier Monday by Chinese health officials who said oversulfated chondroitin sulfate was not responsible for the reported injuries and deaths.

For the Nature Biotechnology paper, researchers from MIT, the FDA, and elsewhere analyzed six heparin preparations that had been linked with adverse reactions in patients, as well as four "control" preparations not associated with adverse events.

All the preparations linked with adverse reactions contained a contaminant similar to chemically synthesized OSCS, the researchers said. According to the FDA, contaminated heparin has now been linked to as many as 81 deaths and hundreds of injuries in United States.

Armed with information on the chemical structure of the contamination, experts should now be able to distinguish pure heparin from tainted heparin, the study authors stated.

The New England Journal of Medicine paper details a screening test for oversulfated chondroitin sulfate, and also demonstrates that heparin contaminated with OSCS and synthetically-derived OSCS result in side effects in pigs similar to those seen in humans.

Raw heparin is derived from pig intestines, and it's often processed by small, unregistered mom-and-pop workshops in China. Heparin is used for certain types of surgery to prevent blood clots. Kidney patients also take it before undergoing dialysis.

Oversulfated chondroitin sulfate mimics heparin's qualities and is a modified form of chondroitin sulfate. Chondroitin sulfate is a naturally occurring substance made from animal cartilage and is often used in supplements to treat arthritic joints. But, oversulfated chondroitin sulfate is man-made and doesn't occur naturally.