Three other people have been put in the isolation ward at Kericho Referral Hospital following an Ebola scare.
The husband of the woman who was admitted on Sunday night and two others who assisted him to take her to hospital have been placed in isolation even though they had not shown signs of the disease.
"We have taken precautionary measures as a result of the reported case, by placing the three in isolation as the matter is being handled" said Dr Shadrack Mutai, the County Executive in charge of Health services.
The World Health Organisation (WHO) has also dispatched experts to Kericho who are already helping with investigations of the case.
Results from Kenya Medical Research Services (Kemri), which is testing blood samples from the patient, are expected to be ready within the next 12 to 24 hours.
On Sunday, the woman who had travelled from Malaba, a town in Busia County on the eastern border of Kenya and Uganda, was admitted at Siloam hospital before being transferred to Kericho Referral Hospital after suspensions of symptoms of the fever.
Kenya is on a red alert over Ebola after the disease spread to neighbouring Uganda from Democratic Republic of Congo where it has killed more than 1,400 people.