ASO Titers & Anti-DNase B: When They Matter, When They Don't, and the Jones Criteria Refresher
ASO Titers & Anti-DNase B: When They Matter, When They Don't, and the Jones Criteria Refresher Stop ordering ASO for every sore throat. It's only relevant when you suspect a post-streptococcal complication—not for diagnosing acute pharyngitis. What ASO and Anti-DNase B Measure Both are antibodies against Group A Streptococcus (GAS) antigens. They indicate prior streptococcal infection—not current infection. They peak 3–6 weeks after the strep infection and decline over months. ASO (Anti-Streptolysin O) : Rises after pharyngeal GAS infection. Peaks at 3–5 weeks. More sensitive for post-pharyngitis complications (ARF, PSGN). Anti-DNase B : Rises after both pharyngeal AND skin GAS infections. Peaks at 6–8 weeks. More sensitive for post-skin-infection complications (especially PSGN after impetigo). Stays elevated longer than ASO. The #1 Misuse ASO should NOT be ordered to diagnose acute strep pharyngitis. The rapid strep test and throat culture are the tests for...