CRP & ASO

For MBBS students

1. CRP & ASO Dr.P.B.PRAVEENKUMAR FIRST YEAR POST GRADUATE DEPARTMENT OF MICROBIOLOGY THANJAVUR MEDICAL COLLEGE

2. HOW TO APPROACH THIS PRACTICAL EXERCISE IN EXAM???? AIM PRINCIPLE PROCEDURE INTERPRETATION

3. C-Reactive protein (CRP) AIM : This test is used for the qualitative and semiquantitative in-vitro determination of inflammatory diseases.

4. PRINCIPLE RAPID LATEX SLIDE AGGLUTINATION TEST : Uniform latex particles are coated with anti-human CRP. The specimen containing CRP, on mixing with latex Reagent agglutinates, showing the positive test result. If CRP is absent there will be no agglutination, indicating a negative test result.

5. PROCEDURE QUALITATIVE METHOD : *Bring the reagents and samples to room temperature *Put three circles in slide for PC,NC & Test. *Add 25 microlitres of PC,NC & Test in corresponding circles. *Add 25 microlitres of CRP latex reagent to all three circles. *Spread it over the circle using separate sticks for each sample. *Rock the slide to and fro gently for two minutes(Not beyond 2 minutes) & See for agglutination.

6. INTERPRETATION OF QUALITATIVE TEST *Agglutination within two minutes – CRP POSITIVE *No agglutination / smooth suspension – CRP NEGATIVE

7. PROCEDURE (cont.) SEMIQUANTITATIVE METHOD : *Dilute the specimen serially in the ratio of 1:2, 1:4, 1:8, 1:16, 1:32, 1:64 using normal saline. *Add one drop of latex reagent in each of these circle. Mix well with separate applicator stick. *Rock the slide gently to and fro for two minutes and examine for agglutination.

8. INTERPRETATION (cont.) OF SEMIQUANTITATIVE TEST Concentration of CRP (mg/dl) = Sensitivity (0.6 mg/dl) * Titre (Highest dilution) For example : Agglutination stopped in 1:32 titre means CRP Concentration = 0.6*32 19.2 mg/dl

9. Anti streptolysin O (ASO) AIM : This test is used for the qualitative and semi quantitative in-vitro determination of ASO in patient serum.

10. PRINCIPLE LATEX SLIDE AGGLUTINATION TEST : The ASO latex is a slide agglutination test for the qualitative and semi quantitative detection of anti- streptolysin O (ASO) in human serum. Latex particles coated with streptolysin O (SLO) are agglutinated when mixed with samples containing ASO.

11. PROCEDURE QUALITATIVE METHOD : *Bring the reagents and samples to room temperature *Put three circles in slide for PC,NC & Test. *Add 50 microlitres of PC,NC & Test in corresponding circles. *Add 50 microlitres of ASO latex reagent to all three circles. *Spread it over the circle using separate sticks for each sample. *Rock the slide to and fro gently for two minutes(Not beyond 2 minutes) & See for agglutination.

12. INTERPRETATION OF QUALITATIVE TEST *Agglutination within two minutes – ASO POSITIVE ( INDICATES ASO TITRE EQUAL / GREATER THAN 200 IU/ML) *No agglutination / smooth suspension – ASO NEGATIVE

13. PROCEDURE (cont.) SEMIQUANTITATIVE METHOD : *Dilute the specimen serially in the ratio of 1:2, 1:4, 1:8, 1:16, 1:32, 1:64 using normal saline. *Add one drop of ASO latex reagent in each of these circle. Mix well with separate applicator stick. *Rock the slide gently to and fro for two minutes and examine for agglutination.

14. INTERPRETATION (cont.) OF SEMIQUANTITATIVE TEST Concentration of ASO (IU/ml) = 200 * ASO titre (Highest dilution) For example : Agglutination stopped in 1:16 titre means ASO Concentration = 200 * 16

15. THANK YOU