The patient, who is currently in isolation, was first admitted at a hospital in Enköping -- about 50 miles (80km) from Stockholm -- before being transferred to Uppsala.
Ebola -- which causes fever, severe headaches and in some cases hemorrhaging -- kills about half of those infected.
Authorities said the emergency room at Enköping has since closed and staff who were in contact with the patient are being looked after.
Test results are expected to come back tonight, Uppsala's regional authority said in a statement, reiterating that "it is only a matter of suspicion" and that it could be another disease.
Cases of Ebola are very rare in Europe, with one case reported in Italy in 2015, one in Spain in 2014 and one in the UK the same year, according to the WHO
The Democratic Republic of Congo is going through the second-deadliest and second-largest Ebola outbreak in history, with cases surpassing 600 on Wednesday. This is topped only by an outbreak in West Africa in 2014 when the disease killed more than 11,000 people, according to the World Health Organization.