Clinical Information

Elevated values are consistent with an antecedent infection by group A streptococci. However, the use of the antistreptolysin O (ASO) for the diagnosis of an acute group A streptococcal infection is rarely indicated, unless the patient has received antibiotics that would render the culture negative. There are certain limitations to the use of the ASO test in these circumstances due to the delay and attenuation of the immune response following early antibiotic therapy.