Irvine-based Quality Systems Inc. sold the hospital software division of its NextGen Healthcare subsidiary to Reston, Va.-based QuadraMed Affinity Corp. A purchase price was not disclosed.

Quality makes software that doctors and dentists use to manage their practices.

QuadraMed makes healthcare software used mainly in hospitals, health systems and related facilities in the U.S., Canada, United Kingdom and Saudi Arabia. It is part of the Harris Operating Group of Toronto-based Constellation Software Inc.

Selling the hospital unit “enables Quality Systems and NextGen Healthcare to focus on our core ambulatory business, which includes one of the largest installed bases in the industry,” Chief Executive Rusty Frantz said.

Quality released the news after markets closed today. The company’s shares closed down 1% to a market value of $776 million.