CAMBRIDGE, Mass. — Biotech company Genzyme is selling its diagnostics business to Sekisui Chemical for $265 million, Genzyme said Thursday.

Under the deal, Sekisui will purchase the diagnostics business’ assets, including product lines and technologies, and offer employment to its 575 employees while maintaining operations in all of its current locations.

“With this transaction, we are continuing to execute on our plan to increase value for shareholders,” Genzyme chairman and CEO Henri Termeer said. “This sale is part of our strategy to sharpen the company’s focus and allocate our resources to key areas for our future growth, such as manufacturing, our rare disease business and our product pipeline.”

The diagnostics business is one of three that Genzyme has sought to sell off, the other two being Genzyme Genetics, which it sold to Laboratory Corp. of America in September, and the pharmaceuticals business, which it has yet to sell.