HIV Testing and Systems for Managing HIV Implementation in Resource Limited Settings

Transcription

1 HIV Testing and Systems for Managing HIV Implementation in Resource Limited Settings Elizabeth M. Dax with the staff of the National Serology Reference Laboratory, Australia

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4 My Background Worked in HIV since 1986 when performing clinical studies in NIDA-USA realised that 30% of our subjects were infected. Since 1990: Director: NRL, Australia- Evaluates HIV and other kits pre- and post- market. Set standards & strategies Not a pathologist Involved in international programmes for Laboratory development (WHO, CDC, APHL, ASHM, AIC etc)

5 Evolution in Titles of the Present Talk HIV Testing and Systems for Managing HIV Implementation in Resource Limited Settings Laboratory Monitoring in the Context of ARV Implementation in Resource-Limited settings Laboratory Monitoring of HIV Infection and Efficacy of ARV Treatment

6 Assumptions around Titles Unimportant in the present context Of importance is that 95% of HIV infected people do not have adequate access to laboratory screening, diagnostic or monitoring services. Many services are of poor quality Most are not appropriately quality assured

7 Assumed that:- Clinical Medicine Therapy Good Quality Medical Care Laboratory Support Diagnostics, Monitoring, Blood screening

8 Successful Testing Systems Suitable policies Effective procurement and distribution Regulation (for tests, laboratories, clinical practice) Laboratory systems (accredited to international standards) Efficient management systems Quality assurance and safety considerations

9 Involves Government Policy Regulators Laboratory systems Audit & Accreditation system QM & QA

10 Laboratory Systems NRL(s) Central (Reference) Labs Intermediate Labs Peripheral Labs Health Care Settings

11 Laboratory Systems - NRL NRL(s) Central (Reference) Labs Intermediate Labs Peripheral Labs Health Care Settings Offers a full range of services Reference testing Quality guidance and programmes Operates high throughput strategies Adjudicates Sets standards Educates

12 How does NRL assure high quality results? Makes Evaluations sure kits are of of Test high Kits integrity Performance Monitoring Methods: Assures precision QC & accuracy Quality Periodically QAP checks Management processes Monitoring Specificity Batch Checks batch integrity Creates sample Reference testing repositories Testing Assures strategy correct development test usage *Education Training & programmes* networking Delivers reports and programs to generate quality in laboratories

13 Central Laboratories NRL(s) Central (Reference) Labs Intermediate Labs Peripheral Labs Health Care Settings Offer a range of services (+ confirmatory) + Reference testing Lead in performing quality programmes Operate intermediate throughput strategies Publicly conform to quality standards Educate

14 Intermediate Laboratories NRL(s) Central (Reference) Labs Intermediate Labs Offer range of tests for basic diagnosis, monitoring Refer samples as necessary Operate to quality assurance and management principles Peripheral Labs Health Care Settings

15 Peripheral Laboratories NRL(s) Central (Reference) Labs Intermediate Labs Basic services Refer samples Follow quality management and assurance principles Peripheral Labs Health Care Settings

16 Health Care Centres NRL(s) Central (Reference) Labs Intermediate Labs Peripheral Labs Rapid test diagnosis Refers samples or patients for further testing Basic quality principles followed Health Care Settings

17 Expectations of Laboratories To produce precise and accurate results To deliver results in a timely manner To attain accreditation to international standards To maintain the health and safety of personnel

18 Monitoring Infections Maximises:- Good management Treatment efficaciousness Avoiding drug resistance Management of toxicities

19 NRL s EQAS in SEAWP Regions External Quality Assessment Scheme (EQAS) to SEA-WP - since 1989 EQAS Provider Send samples Analyse results Provide feedback EQAS Participant Test samples Return results Review feedback Improve process In 2003 EQAS for anti-hiv, anti-hcv and HBsAg

20 NRL s EQAS in SEAWP Regions 15 panels for anti-hiv between 1989 and laboratories 29 countries Collected 13,979 results

21 Comparative Error Rates Overall error rate for SEA-WP 2.5% 0.8% in Australia Why do laboratories in SEA-WP have more errors than in Australia?

22 Errors by Laboratory type 6 5 Anti-HIV EQAS Anti-HCV EQAS Errors (%) Type of Laboratory

23 Errors by Assay Type Manual IA Agglutination Rapid Immunoblot Total Type of Assay used Anti-HIV EQAS Anti-HCV EQAS Instrument-based IA Errors (%)

24 Specific Errors Poor sensitivity, specificity of kits No confirmatory testing Sample mix-up Incorrect interpretation Subjective results not checked Carry over Inadequate sample preparation

25 Errors for anti-hiv and anti-hcv EQAS Anti-HIV EQAS Anti-HCV EQAS Total Test Interpretations Overall Error Rate* 1.6% 1.4% False Reactives 85.9% 60.7% False Negatives 14.1% 39.3% *Error rate = number of incorrect test interpretations expressed as a ratio of the total interpretations reported.

26 Errors leading to an incorrect sero-status Anti-HIV EQAS Anti-HCV EQAS % of errors that resulted in an incorrect Sero-status assigned 53% 84% Many errors resolved during subsequent testing Subsequent or confirmatory testing not performed in most laboratories

27 Performance over time in EQAS Examples from two laboratories Error rate (%) Introduced new assay Error rate (%) Introduced new assay 0 0 Panel (Year) Panel (Year)

28 Detection - HIV-1 Group O Percent TMA Roche copies/ml TMA (Chiron) Roche (HIV-1 Ampliscreen)

29 ARV Resistance Labs ability to detect nucleotide mixtures Nucleotide Mixtures (%) Panel 1 Panel 3 Panel 5 Panel 7 Laboratory ID

30 What is Needed Better government involvement in laboratory Better systems Improved systems Better management and safety Better and more appropriate tests e.g. RT assay for viral load Physician/researcher involvement

31 New Approaches Referral systems rather than more laboratories Transport systems Better tests for use in resource-limited settings NRL Central (s) Intermediate (Reference) Peripheral Labs Labs Health Care Settings Improved laboratory development mechanisms including QA Insist on donors supporting systems and infrastructure - not individuals

32 Clinical Medicine Therapy Good Quality Medical Care Laboratory Support Diagnostics, Monitoring, Blood screening