The Sun reported Saturday the 24-year-old singer's tuberculosis tests came back negative after doctors had placed her in isolation after fearing she may have the potentially deadly infectious disease.

A source told British newspaper her family and friends had been forbidden from seeing the "Rehab" star as a medical precaution.

"Doctors have to take this very seriously," the anonymous source said.

"She is coughing and spluttering all over the place so visitors would be at risk of catching whatever she has."

NME.com said Winehouse, who was hospitalized after collapsing at her home Monday, is still scheduled to perform at a 90th birthday celebration in London for anti-apartheid activist Nelson Mandela next weekend.