For the first time, the agency has conclusively linked patient deaths to a foreign substance found in specific lots of the drug made by Baxter International, The Chicago Tribune reports.

The FDA completed its review of 93 death reports related to heparin that were received from January 1 to March 31, a period when there was a dramatic spike in potentially deadly allergic reactions from patients who had been injected with heparin, the paper writes.

Of 10 reports of death from severe shock known as anaphylaxis or hypotension, three could be traced to lot numbers of Baxter products that tested positive for an animal-like substance known as oversulfated chondroitin sulfate. Heparin lot numbers were not known for the other seven deaths from anaphylaxis or hypotension, so the FDA could not determine whether those patients received heparin contaminated with the substance.

“We have what looks like a cause and effect in some patients,” Janet Woodcock, director of the FDA’s Center for Drug Evaluation and Research, tells the paper. “We know that they got contaminated heparin, and they died subsequently. This is one of the final links in the chain.”

Baxter recalled its heparin products in February in the wake of the spike in the number of the allergic reactions. In recent months, federal health officials and Baxter believe the oversulfated chondroitin sulfate was intentionally put into the product from suppliers in China.

Baxter wouldn’t comment. “We haven’t seen this data and look forward to working with [the] FDA to understand this new information,” a Baxter spokeswoman tells the paper. “However, these findings appear to indicate what our own analysis has shown - that only a very small portion of the number of deaths reported seem to have a definitive link to heparin.”

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