1. THE EFFECTIVENESS OF A RE- TESTING PROTOCOL TO ASSURE QUALITY DNA PCR TESTING FOR EARLY INFANT DIAGNOSIS (EID) IN MALAWI XVIII INTERNATIONAL AIDS CONFERENCE JULY 18 – 23 2010, VIENNA AUSTRIA Wainings Manda-EID Lab Coordinator R Mwenda, H Moyo, J.Bitilinyu, C Porter, M Kabue, M Eliya HUTAP

2. Malawi Demographic Profile 2008  Population: 13.6 Million  HIV/AIDS Prevalence - Adult and adolescents: 12%  HIV/AIDS – In children: 30,000 new infections annually  U5MR: 110 deaths per 1,000 live births

3. DNA PCR Laboratory Capacity  EID was implemented in Malawi in 2007  Currently 2 government labs perform PCR  Infants <18 months are testing using DNA PCR on dried blood spots (DBS)  A total of 18,000 infants were tested at the end of 2009.  A total of 4000 HIV-infected infants were identified

4. DNA-PCR Testing Protocol  Initial n  Initial negative result – reported  Initial positive result - re-tested - confirmed pos results are reported  Indeterminate results are retested in duplicate  Invalid- request for a fresh specimen

5. Quality Assurance   Internal Quality Control   Review results before reporting   Inter-laboratory QC   Proficiency Testing & re-testing (CDC- Atlanta)   Staff competency

6. 18,000 DNA-PCR tests by end of 2009

7. Purpose   EID scale up resulting in higher volume   Current protocol requires re-testing all positive results   Re-testing: - expensive - time consuming   Evaluation of retesting protocol was necessary

8. Methods  DNA-PCR test results done in 2009 analyzed.  Assessment of the second test result for all specimens with initial; - positive result - positive result - indeterminate result - invalid result  Electronic data of DNA PCR results were analyzed using STATA™ version 8.

9. Discordance: Initial vs. 2 nd test Name of Laboratory Number of specimens with initial positive test Number of specimens with discordant 2 nd test result Proportion of discordance KCH7318311.35% QECH135815311.27% TOTAL2,08923611.31%

10. Frequency of discordance: 2 nd test

11. Conclusion  89% of initial positives were confirmed positive on re-test  A majority of the discordant specimens re-tested yielded HIV negative results  Re-testing is necessary

12. Lessons learnt  High sensitivity of test assay may contribute to initial false positive results.  Other factors that may lead to initial false positive results are; - human error - contamination of specimens  Re-testing specimens rules out false positive results.

13. Recommendations  Malawi should continue with the current protocol of re-testing all initial DNA-PCR HIV positive results and discordant results.  More specific assays are needed.  Urgently request for re-collection of DBS specimen for invalid result

14. DNA-PCR operation