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: Microbiology
[{'content': 'True statement about Antistreptolysin ‘O’ titre is: \nSelect and explain. \nA. In normal people the titre is <200, B. In acute glomerulonephritis the titre is low, C. ASO titre >200 indicate rheumatic fever, D. Streptozyme test is an active haemagglutination test', 'role': 'user'}, {'content': 'Answer: B \nExplanation: Retrospective Diagnosis of Streptococcal infection\n\nASO (Anti Streptolysin ‘O’) titre :\n\n– Estimation of antibody aganist streptolysin is a standard serological test for retrospective diagnosis of streptococcal infection.\n– ASO titre > 200 are indicative of prior streptococcal infection.\n– Raised after throat infection only\n– Acute rheumatic fever :\n- High level of ASO titre are usually found\n- Titres > 300 or 350 are taken as significant.\n– Acute glomerulonephirits :\n- ASO titres are often low.\n\nStreptozyme test – Passive slide hemaglutination test\n\nBecomes positive after nearly all types of streptococcal infection whether of throat or skin.\n\nAnti DNA ase B and Antihyaluronidase – Useful for retrospective diagnosis of Streptococcal Pyoderma or for acute glomerulogephritis for which ASO titre is of much less value', 'role': 'assistant'}]