ASO test.ppt
- 1. Lecture 2 Agglutination tests Prepared by DHuda Muharram
- 2. Agglutination reaction When a particulate antigen is mixed with its antibody in presence of electrolytes at suitable temperature and pH, then the particles are clumped or agglutinated .
- 3. Agglutination test Qualitative agglutination test - to assay for the presence of an antigen or an antibody. Quantitative agglutination test - to quantitative the level of antibodies to particulate antigens.
- 4. Uses 1. Identification of bacteria, e.g. serotyping of salmonella and shigella with known antisera. 2. Serological diagnosis of infection e.g. widal test for typhoid 3. Haemagglutination test.
- 5. Agglutination tests can be performed 1. On slides or tiles 2. In tubes 3. In microtitration plate
- 6. The type of agglutination Active agglutination:- These are tests in which there is a direct agglutination of Ag on the surface of large insoluble particles ( as bacteria ) with it's corresponding Ab. Passive agglutination :- These are tests in which the specific Ab or known Ag is attached to inert particles or cells (carriers ).
- 7. The substances and cells used as carriers 1. Latex particles 2. Carbon particles 3. Stabilized staphylococcal cells Specific Ab protein A
- 8. Examples of latex agglutination tests ASO latex slide agglutination test Rheumatoid factors (RF) latex slide agglutination test C- reactive protein (CRP) latex slide agglutination test Pregnancy latex slide agglutination tests Hepatitis surface antigen (HBsAg)
- 9. ASO latex slide agglutination test
- 10. Intended use It is a rapid latex agglutination test for the qualitative and semi-quantitative determination of anti-streptolysin-O antibodies (ASO) in serum.
- 11. Causative agent β-haemolytic Streptococci group A (Strept. pyogenes ) Streptolysin-O is one of the exotoxins liberated from the bacteria that stimulates production of ASO antibodies.
- 12. Diseases Sore throat Skin infection Scarlet fever Otitis media Complications Rheumatic fever (after sore throat) Acute glomerulonephritis (after skin infection)
- 13. SO Principle Latex particles coated with streptolysin O are agglutinated when mixed with samples containing ASO.
- 14. Reagents and material 1. ASO latex reagent 2. ASO Positive control 3. ASO Negative control 4. Stirrers & slide
- 15. Sample Fresh serum. Stable 8 days at 2-8ºC or 3 months at –20ºC. Do not use highly hemolized or lipemic samples.
- 16. Procedure Qualitative method Semi-quantitative method
- 17. Qualitative method 50 μL of the sample + One drop of latex One drop of positive control + One drop of latex One drop of negative control + One drop of latex At room temperature Mix than Place the slide on a mechanical rotator at 80-100 r.p.m. for 2 minutes
- 18. Result Positive result :- ASO 200 IU/mL Negative result :- ASO 200 IU/mL
- 19. Semi-quantitative method 1/8 1/4 1/2 Dilutions 50 μL Sample 50 μL 50 μL 50 μL Saline 50 μL 50 μL 200 X 8 200 X 4 200 X 2 ASO conc. 50 μL The titer = the highest dilution showing a positive result
- 20. The approximate ASO concentration in the patient sample 200 x ASO Titer = IU/mL Calculation
- 21. End of lecture