The Food and Drug Administration has announced yesterday that it received 62 reports of deaths during the last 15 months of patients who were treated with the blood-thinner heparin and suffered allergic reactions or low blood pressure. This is more than triple the initial estimate of 19 deaths.

The figure includes deaths of patients taking heparin made by various manufacturers, not just Baxter's which was recalled in February. The figures are worrying because in 2006 only 55 cases of patients who died while taking heparin were recorded, and of those only three were due to allergic reactions. Baxter claims only four deaths can be linked to its tainted heparin.

"The volume of adverse event reports related to heparin has been very high since the initial reports of allergic symptoms and hypotension were first reported," said FDA spokeswoman Karen Riley.

Federal drug regulators announced that the blood-thinning drug Heparin that had been linked to several deaths and hundreds of allergic reactions was contaminated with a fake ingredient got there by mistake or by fraud. The New York Times now reports that the substance used to cut heparin appears to be made from animal cartilage and is seems chemically altered to act like the real drug.

The substance is allegedly over-sulfated chondroitin sulfate, but it is unclear that this was the cause of allergies and deaths. It is also unclear hos it got mixed up in heparin. Chondroitin is also used medically to treat joint pain, but in its natural state it does not have anti-coagulant properties.

The FDA had already requested all heparin manufacturers to conduct specialized nuclear magnetic resonance spectroscopy tests to ensure that the drug, which is derived from pig intestines, is safe.

Routine tests haven’t revealed anything wrong in the heparin produced by Baxter. But high-tech tests, based on magnetic resonance imaging, uncovered that around 20 percent of the product’s active ingredient was a heparin-like compound, a substance that was not found in batches of problem-free heparin. The contaminant is so chemically close to real heparin that Baxter’s standard routine testing could not reveal its presence.

Heparin is derived from pig intestines, and apparently, the heparin-like contaminant is related to a group of chemicals that can also be found in pig intestines. This makes it difficult for the specialists to decide whether the contaminant was blended in the heparin accidentally or intentionally.

Baxter, which used to provide about half of the nation’s heparin supply, recalled all of its heparin products in February, after the blood thinner they manufactured was linked to hundreds of reports of allergic reactions, such as nausea, vomiting and difficult breathing.