Serological testing (e.g., the Weil-Felix test) is typically used to obtain a  definitive diagnosis.  Most serological tests would succeed only after a certain period of time past the symptom onset (usually a week).
Trench fever laboratory findings
Typhoid fever laboratory findings
Scrub typhus laboratory findings
Relapsing fever laboratory findings
Paratyphoid fever laboratory findings
Colorado tick fever laboratory findings
Rift valley fever laboratory findings
Rocky Mountain spotted fever laboratory findings