Mandela, 94, who has not made a public appearance since 2010, is recovering from a lung infection and gallstone surgery, has been convalescing at his home in suburban Johannesburg. The hospital trip was only for observation and evaluation, CNN said Sunday.
South African President Jaco Zuma renewed calls for Mandela's privacy and said the famous anti-apartheid activist is in good spirits.
"The doctors have completed the tests," Zuma said in a statement. "He is well and as before, his health remains under the management of the medical team."