Lecture 7-c-reactive protein
- 1. LECTURE-7 C-reactive protein (CRP) MR.SAID WARSAME NUR
- 2. C-reactive protein (CRP) is a blood test marker for inflammation in the body. CRPis produced in the liver and its level is measured by testing the blood. CRP is classified as an acute phase reactant, which means that its levels will rise in response to inflammation.
- 3. • CRP is prominent among the acute-phase proteins because it provides fast and adequate information of the actual clinical situation; as a result CRP is a direct and quantitative measure of the acute-phase reactions.
- 4. • Measures of CRP add to the diagnostic procedure in selected cases (e-g. in the differentiation between a bacterial and a viral infection). • An extremely elevated CRP is suggestive of a possible bacterial infection. • The CRP level may be useful also for monitoring the effect of treatment and for early detection of postoperative complications or intercurrent infections.
- 5. Tests for CRP • Rapid latex agglutination test • Principle: – The test is based on the reaction between patient serum containing CRP as the antigen & the corresponding antibody coated to the treated surface of latex particle. The coated particles enhance the detection of an agglutinate reaction when antigen is present in the serum being tested.
- 6. Tests for CRP • Specimen- Serum • Reagent & materials required – CRP latex reagent – Glycine – saline buffer – Capillary pipette – Applicator sticks – Glass slide – Serologic pipettes & rubber bulb Quality control Include positive & negative control serum.
- 7. PROCEDURE A.Qualitative Test: • Bring reagents and specimens to room temperature before use. • Place one drop (40 μl) of CRP Positive Control on field #1 of the reaction slide. Place one drop (40 μl) of the CRP Negative Control on field #2. • Using a serological pipette place (40μl) of undiluted test sample to field #3.
- 8. PROCEDURE A.Qualitative Test: • Gently resuspend the CRP Latex Reagent and add one drop to each test field. • Mix well with the provided stirring sticks. • Rotate the slide for 2 minutes and read immediately under an oblique indirect light.
- 10. INTERPRETATION A.Qualitative Test: • A negative reaction is indicated by a uniform milky suspension with no agglutination as observed with the CRP Negative Control. • A positive reaction is indicated by any observable agglutination in the reaction mixture. The specimen reaction should be compared to the CRP Negative Control (
- 11. INTERFERENCES NON INTERFERING SUBSTANCES: • Hemoglobin (10g/dl) • Bilirubin(20mg/dl) • Lipemia(10g/dl)
- 12. NOTE • High CRP concentration samples may give negative results .Re – test the sample again using a drop of 20μl . • The strength of agglutination is not indicative of the CRP concentration in the samples tested. • Clinical diagnosis should not be made on findings of a single test result, but should integrate both clinical an laboratory data.
- 13. LIMITATIONS • Reaction time is critical. If reaction time exceeds two minutes, drying of the reaction mixture may cause false positive results. • Freezing the CRP Latex Reagent will result in spontaneous agglutination. phenomenon (antigen excess). • It is recommended, therefore, to check all negative sera by retesting at a 1:10 dilution with Saline Solution.