<prompt> True statement about Antistreptolysin O titre is:In normal people the titre is 200In acute glomerulonephritis the titre is lowASO titre 200 indicate rheumatic feverStreptozyme test is an active haemagglutination test  <response>: Retrospective Diagnosis of Streptococcal infectionASO Anti Streptolysin O titre : Estimation of antibody aganist streptolysin is a standard serological test for retrospective diagnosis of streptococcal infection. ASO titre 200 are indicative of prior streptococcal infection. Raised after throat infection only Acute rheumatic fever :- High level of ASO titre are usually found- Titres 300 or 350 are taken as significant. Acute glomerulonephirits :- ASO titres are often low.Streptozyme test Passive slide hemaglutination testBecomes positive after nearly all types of streptococcal infection whether of throat or skin.Anti 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 