All of the following are TRUE about ASO titre, EXCEPT:
The antistreptolysin O (ASO) titer is the most commonly used streptococcal antibody test to establish a recent streptococcal infection. It is not a major criteria but, suppoing evidence of antecedent group A streptococcal infection. An ASO titer of 240 Todd units or higher in adults or 320 Todd units or higher in children is considered modestly elevated. ASO titers above 500 Todd units are uncommon in healthy individuals and therefore would serve as evidence of a recent streptococcal infection. Ref: Jaggi P., Shulman S.T. (2013). Chapter 52. Rheumatic Fever. In J.B. Imboden, D.B. Hellmann, J.H. Stone (Eds), CURRENT Diagnosis & Treatment: Rheumatology, 3e.
ASO can be increased in school children
May be negative in post streptococcal glomerulonephritis
ASO titre included in major criteria in jones criteria
May not be elevated in 20% cases of carditis