Joan Rivers' outpatient clinic has denied a report that the late comedian underwent an unplanned throat biopsy which resulted in complications which stopped her breathing and led to her death.

"A biopsy of the vocal cords has never been performed at Yorkville Endoscopy," the New York City clinic said in a media statement obtained by TheWrap.

According to the New York Daily News, the Joan & Melissa: Joan Know Best? star and The Celebrity Apprentice winner was put under general anesthesia at the clinic.

"General anesthesia has never been administered at Yorkville Endoscopy," the clinic insisted. "The type of sedation used at Yorkville Endoscopy is monitored anesthesia care. Our anesthesiologists utilize light to moderate sedation."

Rivers' representatives and her daughter Melissa declined comment on the Yorkville Endoscopy denial.

The outpatient clinic reportedly typically deals with digestive issues and Rivers went in for a routine endoscopy on August 28.

However, the clinic's doctor noticed "something" on Rivers' vocal cords, according to a Daily News source, resulting in another doctor and member of Rivers' entourage asking the clinic if he could use their instruments to investigate the issue further.

"He asked and they let him," the source said, adding that Rivers' doctor had identified himself as an ear, nose and throat specialist. "A huge no-no."

The report continued to claim that Rivers' doctor proceeded to perform an unplanned biopsy which caused the vocal cords to seize -- a medical condition called laryngospasm -- and cut off her air supply, according to the source.

"A biopsy like that should only be done in a hospital setting," the source told the Daily News of the procedure, which Rivers had allegedly not approved. "If she had been in a hospital when it happened, she might have been okay."

The clinic reportedly called 911 at approximately 9:39AM and then paramedics and other first responders arrived at the scene seven minutes later. Rivers was already on life support when she arrived at Mount Sinai Hospital, the nearest hospital, at 10:08AM, and according to reports, she remained on life support until September 4 when Melissa removed it.

Rivers passed away at age 81.