Immucor Inc. replied on Tuesday to a warning letter from the Food and Drug Administration that pointed out problems of manufacturing practices in the company.

Shares of the developer and manufacturer of blood-testing systems declined near 5 percent.

The letter addressed by the U.S. regulator was dated May 2 and says the company failed to establish and maintain procedures to control product that does not conform to specified requirements.

We take our regulatory responsibilities very seriously and are working diligently to respond to the FDA as soon as possible. The FDA has not ordered the recall of any of our products, or placed any limitations on the manufacture or distribution of any of our products. Said Immucor Chief Executive Officer Gioaccino De Chirico.

During an inspection in January, investigators described a number of significant objectionable conditions related to Immucor's facility's compliance with current good manufacturing practice, the latter states.

Shares of Immucor, Inc. fell 4.51 percent to $26.70 at the closing of Tuesday trading on Nasdaq.