Which laboratory finding supports acute rheumatic fever?

Study for the Medical Council of Canada Qualifying Examination (MCCQE) I. Engage with flashcards and multiple-choice questions with detailed feedback. Prepare confidently!

Multiple Choice

Which laboratory finding supports acute rheumatic fever?

Acute rheumatic fever is a post-streptococcal autoimmune reaction that follows a GAS infection. The best lab finding to support this diagnosis is elevated antistreptolysin O antibodies, which indicate a recent GAS exposure compatible with the illness. A positive blood culture for GAS would reflect an active infection rather than the post-infectious process driving ARF. Elevated C-reactive protein is a non-specific marker of inflammation and doesn’t confirm prior GAS exposure, while a positive ANA points to other autoimmune diseases and not ARF. So, a raised ASO titer specifically supports a recent GAS infection, which is the key evidence needed to support acute rheumatic fever.

Acute rheumatic fever is a post-streptococcal autoimmune reaction that follows a GAS infection. The best lab finding to support this diagnosis is elevated antistreptolysin O antibodies, which indicate a recent GAS exposure compatible with the illness. A positive blood culture for GAS would reflect an active infection rather than the post-infectious process driving ARF. Elevated C-reactive protein is a non-specific marker of inflammation and doesn’t confirm prior GAS exposure, while a positive ANA points to other autoimmune diseases and not ARF. So, a raised ASO titer specifically supports a recent GAS infection, which is the key evidence needed to support acute rheumatic fever.

More practice questions