Final answer:
The specific diagnostic study for rheumatic fever other than JONES criteria is the Anti-streptolysin O (ASO) titer, which measures antibodies indicating a recent streptococcal infection, critical for diagnosing rheumatic fever.
Step-by-step explanation:
A diagnostic study specific for rheumatic fever that is other than the JONES criteria is the Anti-streptolysin O (ASO) titer test. This test measures antibodies against streptolysin O, a substance produced by group A Streptococcus bacteria, which cause streptococcal pharyngitis. An elevated ASO titer indicates a recent streptococcal infection, which is important because acute rheumatic fever is a sequela of streptococcal pharyngitis. The detection of these antibodies plays a critical role in diagnosing rheumatic fever, particularly when antimicrobial therapy is needed to prevent the progression of disease and the development of comorbidities such as arthritis and carditis. Unlike the acute-phase proteins such as C-reactive protein (CRP), which are non-specific markers of inflammation, the ASO titer is more specific for streptococcal infections.