Joan Rivers Joan Rivers

Officials at an outpatient clinic in Manhattan have denied a report that said doctors performed an unplanned throat biopsy on Joan Rivers when she stopped breathing on Aug. 28, according to TheWrap.

"A biopsy of the vocal cords has never been performed at Yorkville Endoscopy," the clinic told TheWrap in a statement. "General anesthesia has never been administered at Yorkville Endoscopy."

Could Joan Rivers' death have been prevented?

On Wednesday, the New York Daily News reported that Rivers' personal doctor performed an unplanned throat biopsy on the comedienne after one of the clinic's doctors noticed something on her vocal cords during a routine procedure. As a result, a source told the paper, Rivers' air supply was cut off and she stopped breathing, prompting doctors to call 911. The Fashion Police star never regained consciousness and died on Sept. 4.

The source who spoke to the Daily News said Rivers' death may have been prevented if the biopsy had been performed in a hospital rather than at the clinic. Prior to undergoing the procedure on her vocal cords, Rivers had reportedly signed off on an endoscopy but not a biopsy.

An autopsy of Rivers was inconclusive, and her death is being investigated by the State Health Department and the New York City medical examiner.