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ASO (Ani Streptolysin O)

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Presentation on theme: "ASO (Ani Streptolysin O)"— 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 ASO an enzyme inhibition test
Tube NO. 1 2 3 4 Red cells control SO control ASO Buffer 0.2 0.4 0.6 0.7 1.5 1 (ml) Serum 0.8 0.3 -- SO 0.5 20 min in room temperature Red blood cells Titer (Todd) 125 166 250 333 No lysis lysis

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 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 Serologic 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
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 Old serum

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