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)