Rapid Diagnostic Tests for Rapid Diagnostic Tests for SyphilisSyphilisJonathan B. NdziJonathan B. Ndzi
IAWG, NairobiIAWG, Nairobi
October 9, 2007October 9, 2007
Magnitude of syphilisMagnitude of syphilis
MDGs involvedMDGs involved
4. Reduce child mortality
5. Improve maternal health
6. Combat HIV/AIDS, malaria and other diseases
Laboratory Diagnosis Laboratory Diagnosis
• Blood serum for antibodies detection
a. Non-specific: non-treponemal tests (lipoidal antibody)
• Rapid Plasma Reagin RPR
• Venereal Disease Reference Laboratory VDRL
b. Specific: treponemal tests• Treponema pallidum HemAgglutination assay TPHA
• FTP-ABS
• Treponema pallidum Particle Agglutination assay TPPA
Non-Treponemal Vs Treponemal testsNon-Treponemal Vs Treponemal tests
Non-Treponemal1. Simple, cheap
2. Distinguish between active and non active infections
3. Require electricity, refrigeration, trained personnel
4. Need for serum
5. False positives
6. False negatives with excess antibody (prozone effect)
Treponemal
1. Simple
2. uses whole blood/ serum/ plasma
3. Transport at temp.<30 C
4. No prozone effect
5. Long lasting antibodies
Rapid Diagnostic TestsRapid Diagnostic Tests
Advantages i. No trained technical
staff
ii. No refrigeration
iii. No electricity
iv. Immediate results
v. Highly specific and sensitive
vi. Emergencies for Antenatal screening and blood transfusion
Disadvantagesi. No distinction between
new and treated infection
ii. Some results are not consistent with batches
iii. False positives with other treponemes (yaws & pinta)
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