2 ASO A diagnosis test for: Acute rheumatic fever (2-3% Pharyngitis-Tonsilitis)( Antigeng M)Rheumatic heart diseaseAcute post streptococcal glomerulonephritis (2-5% Chronic) (Streptokinase)
3 Streptococcal Antibody Test Streptolysin O: An exotoxin which is sensitive to oxygen.
4 General pattern of antibody response to group A streptococcal extracellular antigen
5 ASO an enzyme inhibition test Tube NO.1234Red cells controlSO controlASO Buffer0.20.40.60.71.51 (ml)Serum0.80.3--SO0.520 min in room temperatureRed blood cellsTiter (Todd)125166250333No lysislysis
6 Todd Unit: concentration of ASO which neutralize completely 2 Todd Unit: concentration of ASO which neutralize completely 2.5 minimum hemolytic dose of SO. minimum hemolytic dose of SO :the smallest amount of SO that produces complete lysis of 0.5 ml of 5% red blood cells at 37°c in 1h. The unit in which the results of testing for antistreptolysin O (ASO) are expressed. It denotes the reciprocal of the highest dilution of test serum at which there continues to be neutralization of a standard preparation of the streptococcal enzyme streptolysin O.
7 Interpretation of the result Different factors such as age ,previous infection, immune system status & society affect the ASO interpretationTiter in adults: 250 unitAcute rheumatic fever (85%)Todd Acute post streptococcal glomerulonephritis (ADNaseB)
10 Laboratory diagnosis Microscopic Tests Serologic Tests Dark field ImmunoflurescenseSerologic TestsScreening non-Treponema tests (non-specific/VDRL, RPR)Confirming Treponema tests (specific/FTAabs)
11 Interpretation of the result Flucculation (negative/ weak positive/ positive)Titration (1/8, 1/16, 1/32)Primary syphilis: 30% Neg (repeat after 1w/ 1&3mo)Titration is used for confirming of threapySecondary syphilis: 100% psitive &over 1/16Late latent syphilis: 20% Neg