Nelson Mandela was in hospital for "routine" tests on Wednesday but his health was not in jeopardy, said the former South African president's foundation in a statement.
"He is in no danger and is in good spirits," the foundation said, confirming that he attended Milpark hospital in Johannesburg.
An AFP photographer saw Mandela's wife, Graca Machel, leaving the hospital at around 5:30 pm (1530 GMT), with four other family members departing shortly after. His personal assistant Zelda la Grange arrived at 6:00 pm.
The hospital declined to comment on whether the anti-apartheid hero would be staying in hospital overnight, saying it did not give information on patients as a matter of policy.
President Jacob Zuma, who is in Switzerland for the World Economic Forum, had not changed his travel plans because of the news, his office said.
"The president is in Davos and will be there until January 28," spokesman Zizi Kodwa told the Sapa news agency.
"From there, he is flying to Addis Ababa in Ethiopia to attend the African Union Summit. The programme has not changed."
Mandela, South Africa's first black president, is increasingly frail and has not appeared publicly since the closing ceremony of the 2010 FIFA World Cup in Johannesburg.
After his withdrawal from public life in 2004, he created the Nelson Mandela Foundation, the Nelson Mandela Children's Fund and the Mandela Rhodes Foundation to continue humanitarian work on his behalf.
