ASO (Ani Streptolysin O) Dr. M. Izad
Apr 02, 2015
ASO(Ani Streptolysin O)
Dr. M. Izad
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)
Streptococcal Antibody Test
Streptolysin O: An exotoxin which is sensitive to oxygen.
General pattern of antibody response to group A streptococcal extracellular antigen
Tube NO.1234Red cells control
SO control
ASO Buffer
0.20.40.60.71.51( ml)
Serum0.80.60.40.3----
SO0.50.50.50.5--0.5
20 min in room temperature
Red blood cells
0.50.50.50.50.50.5
Titer (Todd)
125166250333No lysislysis
ASO an enzyme inhibition test
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.
Interpretation of the result
Different factors such as age ,previous infection, immune system status & society affect the ASO interpretation
Titer in adults: 250 unit 300-1500 Acute rheumatic fever (85%)
Todd Acute post streptococcal glomerulonephritis
(ADNaseB)
VDRL(Veneral Disease Research Laboratory)
&
RPR(Rapid Plasma Reagin)
Syphilis (Treponema Pallidum)
• Primary syphilis
•Secondary syphilis
•Latent syphilis
•Tertiary/ late latent syphilis
Laboratory diagnosisMicroscopic Tests
Dark fieldImmunoflurescense
Serologic TestsScreening non-Treponema tests (non-specific/VDRL, RPR)
Confirming Treponema tests (specific/FTAabs)
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
False positive & False negativeFalse positive:
Intravenous drug users (10% FP)PregnancyAutoimmune disease (Rheumatoid Arthritis, lupus)Aged individualsChronic infection (leprosy)
False negative:Prozone phenomena (FN /1-2% secondary syphilis)
Latent syphilis
CRPC-Reactive Protein
Acute Phase Protein
Passive agglutination
the increase of CRP serum concentrations observed in
• Microbial infections
• Acute rheumatic fever
• Acute myocardial infarction
• Rheumatoid Arthritis
• Cancer
CRP
• Severity of the disease & effectiveness of therapy
• False positive:– Corticosteroids– Prozone
• False positive:– Old serum