To confirm a Yellow Fever infection, doctors typically use blood tests to detect the presence of the Yellow Fever virus or specific antibodies produced in response to the infection. The most common tests are enzyme-linked immunosorbent assay (ELISA) for detecting IgM antibodies, or PCR (polymerase chain reaction) to detect viral RNA. These tests can take several days for results, depending on the laboratory's capacity. Early diagnosis can be difficult since Yellow Fever shares many symptoms with other mosquito-borne diseases, like malaria and dengue, which can lead to misdiagnosis, especially in the early stages. A definitive diagnosis usually requires confirmation from specialized labs due to the overlapping symptoms and the necessity of ruling out other illnesses.