He travelled to the island four months ago to have surgery for cancer there.
“Everything went perfectly. I got top marks, 20 out of 20,” he told reporters.
Mr Chavez had previously described his treatment as successful. But secrecy about his illness fuelled speculation it may be worse than officially stated.
The 57-year-old leader, who has been in power since 1999, says his illness will not stop him from standing for re-election next year.
Last month, he denied US media reports that he had been rushed to hospital with kidney failure linked to his cancer treatment.