"A total of 15 positive results of the new type of coronavirus had been detected" in the lab, CCTV said.
The World Health Organization (WHO) said in a statement Wednesday that a new coronavirus could not be excluded as a possible cause of the disease.
China ruled out SARS, which killed hundreds of people more than a decade ago, in a statement on Sunday.
Wuhan's health commission said on Sunday that seven of the 59 patients were seriously ill but that none had died. All patients received treatment in quarantine.
Eight patients have recovered and been discharged from hospital, state news agency Xinhua reported Wednesday.