Updated

The medical research companies Quest Diagnostics and Quintiles will form a joint venture to conduct clinical trial laboratory work for drug developers.

Financial terms of the deal were not disclosed Tuesday, although the companies did say that the venture would have brought in about $575 million in revenue last year.

Quest Diagnostics Inc., based in Madison, New Jersey, provides diagnostic testing and other services through a network of laboratories and patient service centers. Quintiles Transnational Holdings Inc., of Durham, North Carolina, provides late-stage clinical testing, project support and planning, among other services. It has more than 32,000 employees and does business in about 100 countries.

Quintiles will hold the majority stake of 60 percent in the joint venture, which will combine resources like Quintiles' Infosario technology platform and Quest's data analytics operations.

The companies expect the deal to close in the third quarter. A spokesman said they have yet to determine where the new venture will be based, but believe that will be cleared up around the time that the deal closes.

Shares of Quest Diagnostics slipped 9 cents to $77.60 Tuesday about an hour before markets opened.

Quintiles closed at $68 Monday after hitting a 52-week high of $68.52 last week. The company went public in 2013.