Kisumu Governor Anyang' Nyong'o was on Sunday flown to Nairobi for specialised treatment following a low blood pressure diagnosis.
Aga Khan Hospital medical superintendent, Dr Sam Oula, said the governor was flown from Kisumu International Airport to the same facility in the capital.
Mr Nyong'o was taken to Nairobi by the Amref Flying Doctors service.
"The governor has been flown to Nairobi for conclusive tests," the doctor said.
“We kept him in the hospital overnight. Though he is stable, we need to [carry out] further tests. We did not have conclusive results.”
Prof Nyong'o felt unwell at Uzima University grounds in the county on Saturday, during the installation of Philip Anyolo as the archbishop of Kisumu.
The governor was admitted to Aga Khan after feeling dizzy during the function.
The doctors stabilised and monitored him and later, his communication secretary said he had been diagnosed with low blood pressure and put on bed rest.