China will send samples from a suspected Sars patient abroad for tests after researchers were unable to confirm whether the man has the deadly virus, the World Health Organisation said on Wednesday.
The decision was likely to delay a final diagnosis - if any is possible - on the 32-year-old television producer in hospital in the southern province of Guangdong with symptoms of Severe Acute Respiratory Syndrome.
The Health Ministry said in a statement the case could not be confirmed as of 10 am (0200 GMT) on Wednesday.
"The suspected case in southern China remains a suspected case," the WHO said on its Web site (www.who.int).
China decided late on Tuesday to send samples to an outside lab affiliated to the WHO, or possibly more than one, but there was no schedule as yet, WHO spokesman Roy Wadia said in Beijiing.
"In this case, it's been so confusing because the few positives that have emerged from the battery of tests are from tests that historically have a high number of false positives," Wadia said.
China quarantined 81 people who had had contact with the TV producer, and the ministry statement said 23 had been released.