Science, health care and technology conglomerate Danaher Corp. (NYSE: DHR – $79.41) said that it would buy molecular-diagnostics company Cepheid Inc. for $53.00 a share, or about $4 billion, in its first major acquisition since spinning off a large chunk of its business. Sunnyvale, California-based Cepheid develops and manufactures fully integrated testing systems that can be used to screen for genetic-based disorders and to manage infectious diseases. Cepheid, with estimated annual revenue of $618 million, will become part of Danaher’s diagnostics unit, joining its Beckman Coulter, Leica Biosystems and Radiometer businesses. The deal is subject to customary closing conditions and regulatory approval and is expected to close by the end of the year. Danaher said it will finance the transaction with cash and new debt and estimates the acquisition will add about 5 cents to earnings per share in the first full year after the deal closes.