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Organization and Planning of HIV Testing for Surveillance Purposes Dr G. Vercauteren Diagnostics and Laboratory Techno PowerPoint Presentation
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Organization and Planning of HIV Testing for Surveillance Purposes Dr G. Vercauteren Diagnostics and Laboratory Technology Essential Health Technologies World Health Organization. National HIV prevalence surveys.

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Organization and Planning of HIV Testing for Surveillance Purposes

Dr G. Vercauteren

Diagnostics and Laboratory Technology

Essential Health Technologies

World Health Organization

national hiv prevalence surveys
National HIV prevalence surveys
  • Obtaining an accurate estimate of the number of people infected with HIV in a country or region is important for the purpose of evaluation, programme planning and advocacy.
  • Large scale national surveys to need to be carefully planned and conducted to ensure cost-effective use of resources.
national hiv prevalence surveys3
National HIV prevalence surveys
  • Population-based surveys
    • Household (men, women, children)
    • Rural -Urban
  • Sentinel surveillance
    • Population groups
    • Pregnant women
    • Sex workers
    • Migrant populations
    • Police-army
    • prisoners
planning a population based survey to measure hiv prevalence 1
Planning a population based survey to measure HIV prevalence (1)
  • Survey objectives
  • Design of the survey
  • Survey population, geographical area, timelines
  • Sampling method
    • Sampling units (households or individuals) Select catch area
  • Calculate sample size
  • Specify data to be included
    • demographic data
    • sexual behaviour data, knowledge related to HIV and reproductive health
    • other biomarkers
  • Design questionnaire for data collection
planning a population based survey to measure hiv prevalence 2
Planning a population based survey to measure HIV prevalence (2)
  • HIV testing
  • Plan the survey budget
  • Ethical principles and approval
  • Design informed consent procedures
  • Plan the survey operations
    • Staff organization
    • Mobilization
  • Prepare manuals and pretest questionnaires and HIV testing procedures
  • Train staff : before field work begins
planning a surveillance survey some laboratory issues
Planning a surveillance survey : some laboratory issues
  • Survey population: Inclusion of children aged 0 – 14 years ?
  • Testing for other biomarkers
    • Anemia
    • Syphilis ; other sexually transmissible infections
    • incidence
  • Approach for HIV testing
    • Specimen type: blood, saliva, urine; DBS
    • Select specific assays & algorithm
    • Ability to distinguish between HIV-1 and HIV-2
    • EIA and/or rapid test
    • Where will the testing take place
    • Quality assurance
    • Biosafety
planning a surveillance survey
Planning a surveillance survey :
  • Budget planning :
    • Estimate Nos of tests for screening, confirmation, do not forget to cost to pilot and QA
    • Training of all staff involved
    • Provision of VCT (referal)
  • Ethical considerations
    • Do no harm, stigma, confidentiality ?
    • Participate in benefits (offer VCT, treatment ?)
    • Study procedures & risks
    • Voluntary nature of participation Ethical approval
  • Informed consent
    • Purpose & procedures
    • Risks & benefits
    • Protection of anonymity and/or confidentiality
    • Clear understandable language, opportunity to ask questions
    • Participation is voluntary (specimen type?)
planning a surveillance survey some laboratory issues8
Planning a surveillance survey : some laboratory issues
  • Planning survey operations
    • Staff organization
      • Define roles and responsibilities & workload
        • Supervisors, Interviewers, Testers, Data entry specialists
    • Mobilization : All relevant players
  • Preparing manuals and pretest them
    • How to collect; store and transport specimen
    • How to perform the testing
    • Assess procedures:
      • Is specimen type acceptable to the population
      • Are logistics in place for specimen collection, transport, verification and storage;
  • Training of staff
    • Train all staff involved
    • In particular if non-laboratory staff will collect specimens and/or carry out testing
    • Ethics and Confidentiality
    • Supervisors how to ensure quality of the processes ( strict labelling procedures, recording of issues)
    • Verification upon receipt in the laboratory
conducting an hiv prevalence survey
Conducting an HIV prevalence survey

1. Field operations

The aim of fieldwork is to collect high-quality information and biological specimens from individuals whilst adhering to the sampling design.

conducting an hiv prevalence survey10
Conducting an HIV prevalence survey

2. HIV testing

a) Collecting, handling, processing and tracking specimens

  • Biological specimens should be clearly labelled with a survey code, e.g a unique identification number assigned at the time of collection.
  • The survey code will link the test result of the specimen to other survey data
  • Storage of specimens depend on the type of specimen
    • Serum: keep at 4°C for upto 7 days, or at -20°C for longer periods
    • DBS: keep at room temp in plastic bag with desicant for max 30 days or at 4°C upto 3 months or at -20°C for longer periods
  • Systematic procedures to reduce transcriptional errors
  • DBS, avoid contamination, eluate properly, be meticulous.
hiv testing strategy for surveillance unlinked
HIV testing strategy for surveillance (unlinked)

Strategy II

A11

A1-

Report negative

A1+

A21

A1+A2-

Report negative2

A1+A2+

Report positive2

1 Assay A1, A2 represent test results from 2 different assays

2 Report: result may be reported negative for surveillance purposes

conducting an hiv prevalence survey12
Conducting an HIV prevalence survey

b) Ensure confidentiality and anonymity

  • Staff taking specimens should not do the testing
  • Databases need to be password protected with restricted access to HIV test results, lock up computers
  • Register of HIV test results and back up files need to be locked up (limited access)
  • Before merging test results with other survey data, all personal information should be removed

c) Providing test results and VCT

3. Data management

  • Data should be entered twice by two independent entry staff to minimize error
  • HIV data should be entered separately

4: Unlinked versus Linked test results

hiv testing approaches
HIV testing approaches
  • Unlinked anonymous testing(without informed consent)
    • Testing of unlinked specimens collected for other purposes
    • No personal identifiers or names obtained, no counselling required
    • Coded specimens
  • Unlinked anonymous testing(with informed consent)
    • Testing of unlinked specimens collected solely for surveillance purposes
    • Informed consent required
    • No personal identifiers or names obtained, no counselling required
    • Coded specimens
hiv testing approaches14
HIV testing approaches
  • Linked confidential testing(with informed consent)
    • Informed consent and pretest & posttest counselling required
    • Personal identifiers or names obtained,
    • Coded specimens; code linked to personal indentifying information
  • Linked anonymous testing(with informed consent)
    • Informed consent and pretest & posttest counselling required
    • Informed consent required
    • No personal identifiers or names obtained
    • Coded specimens; code given to patient/client so only patient can link him/herself to results
quality assurance and safety
Quality Assurance and safety
  • Standard operating procedures need to be followed:
    • Pre-analytical phase
    • Analytical phase
    • Post analytical phase
  • Quality control samples
  • Repeat testing of specimen in both assays in case of discordant results
  • Proficiency testing
  • Retesting of specimens
    • Statistical valid manner
    • In a timely manner
  • Proper handling and disposal of biohazardous waste needs to occur at each end of the day.
re test size to provide 95 confidence to detect at least 1 discrepancy with underlying error 1 3 5
Re-test size to provide 95%confidence to detect at least 1 discrepancy with underlying error 1%_3%_5%
re test size to provide 99 confidence to detect at least 1 discrepancy with underlying error 1 3 5
Re-test size to provide 99%confidence to detect at least 1 discrepancy with underlying error 1%_3%_5%
diagnostics and laboratory technology dlt team
Diagnostics and Laboratory Technology (DLT) Team

www.who.int/diagnostics_laboratory