Final answer:
The most reliable lab tests to rule out rheumatic fever would be the throat culture, ASO titer, CRP, and ESR, as these can indicate a recent streptococcal infection and the presence of inflammation.
Step-by-step explanation:
When considering a diagnosis of rheumatic fever, it's important to identify recent streptococcal infections which can trigger this condition. A throat culture can provide direct evidence of a streptococcal infection, and the Antistreptolysin-O (ASO) titer can detect the presence of antibodies against the bacteria that cause strep throat, indicating a past or current infection. In addition, acute-phase proteins like C-reactive protein (CRP) and the Erythrocyte sedimentation rate (ESR) can be elevated due to the inflammation associated with rheumatic fever. While an Elevated white blood cell count (WBC) can be a sign of infection or inflammation, it is not specific to rheumatic fever. Therefore, the most reliable tests to rule out rheumatic fever would be the throat culture, ASO titer, CRP, and ESR.