The Argentine politician chosen by former President Cristina Fernández to be their party's presidential candidate has checked himself into a hospital to undergo tests for a persistent cough.

Alberto Fernández of the left-leaning Unidad Ciudadana party told C5N television Monday that his personal physician advised him to have a check-up before starting campaigning for October's election against conservative President Mauricio Macri.

Fernández says he has been coughing for two weeks but insists "there is no worrisome issue." He acknowledges he had a clot on a lung a few years ago.

Cristina Fernández surprised Argentines in mid-May when she announced she would run for vice president rather than the presidency. Alberto Fernández isn't related to her, but he served as her chief of staff for part of her time as president.