This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Pediatrics
All of the following are TRUE about ASO titre, EXCEPT: 
Select and explain. 
A. ASO can be increased in school children, B. May be negative in post streptococcal glomerulonephritis, C. ASO titre included in major criteria in jones criteria, D. May not be elevated in 20% cases of carditis
C: ASO titre included in major criteria in jones criteria
Answer: C: ASO titre included in major criteria in jones criteria 
Explanation: 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.