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