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ASO (Ani Streptolysin O) Dr. M. Izad. ASO A diagnosis test for:  Acute rheumatic fever (2-3% Pharyngitis-Tonsilitis) ( Antigeng M)  Rheumatic heart.

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Presentation on theme: "ASO (Ani Streptolysin O) Dr. M. Izad. ASO A diagnosis test for:  Acute rheumatic fever (2-3% Pharyngitis-Tonsilitis) ( Antigeng M)  Rheumatic heart."— Presentation transcript:

1 ASO (Ani Streptolysin O) Dr. M. Izad

2 ASO A diagnosis test for:  Acute rheumatic fever (2-3% Pharyngitis-Tonsilitis) ( Antigeng M)  Rheumatic heart disease  Acute 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 Tube NO Red cells control SO control ASO Buffer (ml) Serum SO min in room temperature Red blood cells 0.5 Titer (Todd) No lysislysis ASO an enzyme inhibition test

6 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.unitresultstesting antistreptolysinreciprocaldilution testserum neutralizationstandardpreparation streptococcalenzymestreptolysin O

7 Interpretation of the result Different factors such as age,previous infection, immune system status & society affect the ASO interpretation Titer in adults: 250 unit Acute rheumatic fever (85%) Todd Acute post streptococcal glomerulonephritis (ADNaseB)

8 VDRL (Veneral Disease Research Laboratory) & RPR (Rapid Plasma Reagin)

9 Syphilis (Treponema Pallidum) Primary syphilis Secondary syphilis Latent syphilis Tertiary/ late latent syphilis

10 Laboratory diagnosis Microscopic Tests Dark field Immunoflurescense Serologic Tests Screening 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 threapy Secondary syphilis: 100% psitive &over 1/16 Late latent syphilis: 20% Neg

12 False positive & False negative False positive: Intravenous drug users (10% FP) Pregnancy Autoimmune disease (Rheumatoid Arthritis, lupus) Aged individuals Chronic infection (leprosy) False negative: Prozone phenomena (FN / 1-2% secondary syphilis) Latent syphilis

13 CRP C-Reactive Protein Acute Phase Protein Passive agglutination

14 the increase of CRP serum concentrations observed in Microbial infections Acute rheumatic fever Acute myocardial infarction Rheumatoid Arthritis Cancer

15 CRP Severity of the disease & effectiveness of therapy False positive: –Corticosteroids –Prozone False positive: –Old serum


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