BEIJING, May 6 (Xinhua) -- Chinese experts said on Tuesday that no direct link between 81 deaths in the U.S. and a substance in blood thinner has been proven.

    Jin Shaohong, deputy director of China's National Institute for the Control of Pharmaceutical and Biological Products, told a press conference that according to a current heparin-related adverse event study, "the direct causal relationship between the heparin substitute (hypersulphated chondroitin sulphate) and the clinical cases of deaths cannot yet be confirmed."

    Jin said at present, apart from the U.S. and Germany, more than 10 countries using heparin products containing "heparin-like substance" had not reported any cases of adverse reactions.

    "U.S. experts also analyzed that the concentrated heparin adverse events which occurred in the U.S. had a certain relationship with the large dose of clinical use and quick injecting speed," he said.

    The US-based Covidien Pharmaceutical Co. and B. Braun Pharmaceutical Co. also bought the raw heparin containing the substance from the US-based Scientific Protein Laboratories (SPL) for injection production, but no serious adverse reactions occurred, Jin said. The SPL owns a Chinese factory in Changzhou that supplies ingredients for heparin.

    The raw materials of the heparin were collected by Changzhou SPL, a branch company under the US-based SPL.

    The legal representative of the Changzhou SPL is an American and daily operation were run by chiefs assigned by the SPL headquarters.

    The production techniques and quality standards were all stipulated by SPL, according to SFDA's investigation.

    He said that serious adverse reactions also occurred in some batches of heparin injection products with raw materials containing no heparin-like substance.

    Jin said adverse reaction cases in the U.S. were all reported by patients themselves via a spontaneous reporting system, lacking doctors' confirmation.

    Jin also said that Baxter International Inc, the U.S. drugmaker that recalled batches of the drug heparin, failed to carry out "necessary" cooperation with the Chinese experts, who were sent to the U.S. to investigate the cause of the contamination.

    " The Chinese experts has asked for the production records, samples and recalled heparins, and Baxter did not provide necessary cooperation", said Jin.

    Jin also said Baxter's move was not conducive to the investigation and the Chinese experts felt "deeply regretful".

    He said further analysis was needed to decide the relationship between heparin-like substance and the deaths.

    The latest development comes after China's Ministry of Health received reports from the State Food and Drug Administration that heparin products had caused serious reactions and even deaths in the United States. Raw heparin produced and exported by some companies in China was involved.

    On April 21, the U.S. Food and Drug Administration reported that 81 deaths were related to the use of heparin products.