Thermo Fisher Scientific, Inc. has signed a definitive agreement to acquire Phadia, a global allergy and autoimmunity diagnostics firm, from European private equity firm Cinven, for approximately $3.5 billion in cash. The transaction is expected to be completed in 4Q11.

Based in Uppsala, Sweden, Phadia develops, manufactures and markets complete blood-test systems to support the clinical diagnosis and monitoring of allergy and autoimmune diseases. Phadia operates through two leading brands: ImmunoCAP for allergy tests and EliA for autoimmunity tests. The company had 2010 total sales of approximately $525 million and employs 1,500 people globally. Phadia will be part of Thermo Fisher’s Specialty Diagnostics business within its Analytical Technologies Segment.

“The acquisition of Phadia is a major step forward in our strategy to enhance Thermo Fisher’s global presence in specialty diagnostics, one of our key growth platforms,” said Marc N. Casper, president and chief executive officer of Thermo Fisher. “This transaction will provide Thermo Fisher with leading allergy and autoimmunity diagnostic testing technologies that expand our specialty diagnostics offerings. Phadia has significant growth opportunities in the large, under-penetrated U.S. market, and can leverage our strong presence in emerging geographies to further accelerate growth.”

“Thermo Fisher brings Phadia a significant opportunity to grow as part of the world leader in serving science,” said Magnus Lundberg, Phadia’s chief executive officer. “We share a culture of innovation and a strong focus on customers, and I am confident that this is a winning combination for our employees and customers around the world.”