The Food and Drug Administration plans to perform an inspection at the Chinese plant that manufactures Baxter International’s heparin medication, the blood thinner whose production was halted this week due to health concerns.

It has come to the Food and Drug Administration’s attention that the Chinese plant where Baxter International’s blood-thinning drug is produced has never been inspected by U. S. regulators, which makes this measure an immediate necessity.

“Preparations are being made to perform an inspection as soon as possible,” FDA spokeswoman Karen Riley told Reuters in an email.

Authorities have yet to determine whether the Chinese factory has had any part in the worrisome reports that have increased in number recently. About 350 people have fallen ill since the end of 2007, after being treated with heparin. Four persons died, the agency reported, although the link with heparin is unclear.

Baxter announced earlier this week that it would suspend production of the drug, after the FDA warned that potentially dangerous and “life-threatening” allergic reactions have been linked to the blood thinner.

Heparin is made from pig intestines and has been used since the 1930s, in critical situations when it is necessary to prevent blood clots; it is widely used in dialysis and heart surgery.

Baxter produces about half of all multiple-dose vials of heparin sold in the United States - 35 million vials. The Deerfield-based company said it has inspected the Chinese facility within the last six months, Reuters reports. The plant is owned by a U.S.-based company, and Baxter plans another inspection in the near future, it said.

Federal health officials are worried that shortages of the product could lead to crisis.

“There is going to be a shortage problem in the immediate and longer-term future with the suspension of the Baxter manufacturing,” said Dr. John Jenkins, director of the FDA's Office of New Drugs. “We are facing a complex situation. It's clear that there are going to problems that health-care providers are going to be facing.”

Millions of lives have been saved through the intravenous medication, the FDA said, because it prevented potentially life-threatening blood clots in arteries, veins and lungs.

On the other hand however, some patients receiving heparin reported symptoms like difficulty breathing, nausea, vomiting, excessive sweating, and rapidly falling blood pressure that can lead to life-threatening shock, the FDA said.

As to the Chinese factory that has come to the U. S. regulators’ attention, this is just another case of Chinese safety and quality standards being questioned, after health concerns were raised over the past years by imports such as toothpaste, toys, seafood and other food products.

Baxter would not name the Chinese plant but did say that it had a 30-year history in producing heparin; the factory had been supplying Baxter for more than 20 years.