ANTI-STREPTOLYSIN “O” LATEX TEST

GROUP 5

-Manuel

-Nuqui

-Olazo

-Ong

-Perez

-Puentespina

INTRODUCTION Group A Hemolytic Streptococci

Also known as Streptococcus pyogenes

1º INFECTION Impetigo Pharyngitis Sore throat Scarlet fever

Scarlet feverImpetigo

Strep throat

2º INFECTION (complication arising from 1º infection)

Acute Glomerulonephritis May follow either a throat or a skin infection. Results to impaired renal function

Rheumatic Fever Sequel to pharyngitis or tonsillitis, and damage to the

smooth muscle of the heart may result

Enlargement of the heart

ASO Test – can detect these nonsuppurative sequelae of streptococcal infection

Inflammation of the joints

Hemolysins:(Destroys both RBC and WBC)

Streptolysin O Discovered by Todd in 1932 Oxygen-labile Has direct action on heart and kidney Produces rheumatic fever & glomerulonephritis Antibodies formed (ASO)

Streptolysin S Stable Cause hemolysis on the blood agar No antibodies formed

Immunology-Serology by R. Rabor (2006)

STREPTOCOCCAL ANTIGENS

STREPTOCOCCAL DIAGNOSTIC MARKERS

Streptolysin OAnti-streptolysin O

antibody (ASO)Hyaluronidase Anti-hyaluronidase (AHL)

Streptokinase Anti-streptokinase (ASK)

Streptococcal deoxyribonucleases

Anti-streptococcal deoxyribonucleases (AND)

Streptococcal nicotinamide adenine dinucleotidase

Anti-streptococcal nicotinamide adenine dinucleotidase (ANAD)

ASO is the most commonly measured

antibody in the serum to diagnose streptococcal infection.

It increases within 1 to 2 weeks after infection and peak between 3 to 6 weeks ff. initial symptoms

Detectable ASO does not occur to all patients = 2 tests for different exotoxin is recommded

Varies with age, geographic location, season

DIAGNOSTIC TESTS FOR STREPTOCOCCAL INFECTION Anti-streptolysin O Titer (ASO Titer)

Anti-streptolysin O Latex (ASO Latex)

Anti-Dnase B Testing

Streptozyme Testing

PRINCIPLE INDIRECT AGGLUTINATION/ PASSIVE

AGGLUTINATION Antigen (Streptolysin O) is enlarged based on an immunologic reaction between

streptococcal exotoxins bound to biologically inert latex particles and streptococcal antibodies in the test sample. Visible agglutination occurs when increased Ab level, are present in the serum.

PROCEDUREPlace 1 drop of the positive control, negative control and test

serum on each of the oval in the glass card.

Add 1 drop of the reagent,Polystyrene latex coated with Streptolysin O, on each of the

oval.

Mix using the dispenstir then gently tilt the glass card

Observe agglutination after

2mins.

Record the results.

ANTIBODY & ANTIGEN

ANTIBODY ANTIGENAnti-streptolysin

“O” in patient serum

Polystyrene latex particles coated with

Streptolysin “O”

REAGENTS

ASO Latex Reagent A suspension of polystyrene particles coated

with streptococcal exotoxins. Must be mixed well before using.

ASO Positive Control A stabilized human serum containing at least

200 iU/ml of ASO reactive with the test reagent.

ASO Negative Control A stabilized human serum containing less than

200 iU/ml of ASO non-reactive with the test reagent. Need not to be diluted.

DESCRIPTION OF TEST: Anti-streptolysin “O” Latex test

Screening test The latex test is a rapid slide test using single dilution of the

patient serum and does not require RBC as an indicator system. Streptolysin O is added to the patient serum in a quantity

sufficient to bind 200 IU of ASO per mL.

Positive result (+): Presence of white agglutinates

Negative result (-): Smooth homogenous milky suspension

INTERPRETATION A positive result means that the Anti-

Streptolysin “O” titer in the serum is more than 200 IU/ML . The sample reaction must be compared to a positive control.

A negative result is not indicative of absence of a Streptococcal infection. The test specificity is high but the sensitivity is much lower.

MANNER OF REPORTING Write:

“POSITIVE (+)” when the presence of agglutination is observed.

“NEGATIVE (-)” when agglutination is not observed.