Current President Jacob Zuma issued a statement Saturday saying Mandela is "doing well and there is no cause for alarm." The reason for the tests were not disclosed.
Mandela has been in frail health and has not made any public appearances for a few years. The 94-yaer-old anti-apartheid icon was moved from his rural home to South Africa's administrative capital, Pretoria.
The news of the hospitalization comes just days after the crash of a military aircraft flying on an unknown mission near Mandela's rural home in which all 11 people onboard were killed.
Mandela was imprisoned for nearly three decades for his fight against apartheid before becoming the nation's president in the country's first fully democratic vote in 1994.
The Associated Press contributed to this report.