Rapid Diagnostic Tests for Syphilis Jonathan B. Ndzi IAWG, Nairobi October 9, 2007

Magnitude of syphilis

MDGs involved 4.Reduce child mortality 5.Improve maternal health 6.Combat HIV/AIDS, malaria and other diseases

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 tests Non-Treponemal 1.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. 1.Simple 2. 2.uses whole blood/ serum/ plasma 3. 3.Transport at temp.<30 C 4. 4.No prozone effect 5. 5.Long lasting antibodies

Rapid 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 Disadvantages i. i.No distinction between new and treated infection ii. ii.Some results are not consistent with batches iii. iii.False positives with other treponemes (yaws & pinta)