Thermo, which announced the deal in May, has forecast a 26 to 30 cents per share boost to its 2012 earnings as a result of the acquisition.

"The Commission concluded that the transaction would not raise competition concerns, because the parties are not close competitors and the merged entity would be constrained by a sufficient number of third party competitors active in vitro autoimmune diseases diagnostics," the European Commission, the EU's competition watchdog, said in a statement.

Phadia, which is being sold by private equity firm Cinven, specialises in tests for airborne, food and pet allergies, and also tests for autoimmune diseases such as rheumatoid arthritis.

Copyright Reuters, 2011