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