A World Health Organization (WHO) expert has arrived in Beijing to help China find out whether the country's first suspected SARS patient in six months has the virus.
Another joint team of WHO and health ministry experts was to head to the southern province of Guangdong to aid testing on the television producer (32), whose temperature was normal and who appeared to be doing well, a WHO spokesman said.
But a Ministry of Health official said it would take "several days" to arrive at a diagnosis.
None of the 42 people quarantined for having been in contact with the patient has developed a fever or shown other symptoms of the deadly virus, officials said.
SARS emerged in Guangdong in late 2002 before it was spread by travellers to nearly 30 countries where some 8,000 infections were registered, spurring mass panic and forcing people to cancel trips and stay away from crowded spots.
Chinese shares inched lower this morning as the SARS scare prompted selling in airline and tourism stocks.
Two recent SARS cases in Singapore and Taiwan were linked to accidents in medical research laboratories. The Singapore patient has recovered and been discharged and the Taiwan patient is expected to be released soon.