ALBANY, N.Y. — New York’s top court has upheld random drug testing of New York City police officers through hair samples, a method considered more effective than analysis of urine. The police union argued that expanded use of the hair testing wasn’t negotiated in their contracts.

The Court of Appeals ruled unanimously that the police commissioner’s disciplinary authority gives him discretion to choose the scientific method and the circumstances that prompt testing.

The ruling Thursday reverses a midlevel court. A lawyer representing the unions declined to immediately comment.