Shares of Agilent Technologies Inc. (NYSE: A), the No. 1 U.S. instrument maker, surged on Thursday after the company announced it's biggest acquisition, the $2.2 billion takeover of Denmark's Dako.

The move is intended to strengthen Agilent's presence in selling tools for cancer detection.

In early activity, Agilent shares rose as much as 5.4 percent to $41.91 on the news. Usually, shares of acquiring companies fall when takeovers are announced. By the close, they'd lost 13 cents and closed at $39.63.

The Santa Clara, Calif., company is acquiring Dako from Swedish private equity firm EQT, which bought Dako in 2007. EQT is controlled by the Wallenberg family, which has major holdings in Swedish companies, including Ericsson (Nasdaq: ERIX) and Electrolux (Pink: ELUXY).

Agilent, which was spun out of Hewlett-Packard Co. (NYSE: HPQ) in 1999, reported on Monday that second-quarter net income rose 28 percent to $256 million, or 72 cents a share, as revenue increased 3 percent, to $1.73 billion.

Agilent's market value is $13.8 billion.