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HIV Rapid Tests 101: Procurement for VCT Service Delivery Dvora Joseph, HIV/AIDS Service Delivery Manager PSI/AIDSMark Presentation for PSI Procurement July 8, 2005 Conventional approach to HIV Testing: ELISA • Enzyme-linked immunoabsorbent assay (ELISA) • Requires machine to measure color change in test wells (spectrophotometer) • Designed for batch testing (>100 specimens at a time) - can be automated • Most useful for surveillance and centralized blood transfusion testing • Centralized QA/QC: Done at National and Regional Laboratories - easy to control • Obtain informed consent and prepare client for HIV testing Limitations of ELISA for VCT • Not flexible (need minimum no. samples filled for maximum efficiency) • Requires specialized equipment (automatic pipettes, incubators, washers, test tubes, etc.) • Requires highly skilled & trained technicians to perform and read results • Machine requires maintenance • Requires venous blood sample and central laboratory • Results can not usually be provided on same-day (1-2 week delay often involved) Rationale for Development of Rapid HIV Testing Technology The rationale for HIV diagnostic testing has changed: Beginning of Epidemic: Clinical confirmation of suspected HIV disease Present Stage of Epidemic: Prevention & care potential of knowing one’s HIV status (VCT setting) Advent of rapid testing technology has simplified HIV testing allowing to move-on-site and away from centralized laboratories Characteristics of HIV Rapid Tests • Based on four immunologic principles: particle agglutination, immunodot, immunofiltration and immunochromatography • Positive test kit result indicated by clumping, a spot, a dot or line (visual to naked eye) • Most rapid tests detect antibodies to both HIV-1 and HIV-2 Advantages of Rapid Tests compared to ELISA • More flexible (efficient for 1 to multiple tests at a time) • Requires minimal equipment and reagents • Does not require highly trained or skilled staff • On-site clinic testing can be performed easily • Very easy to interpret test results (naked eye) • Samples can obtained less invasively (finger-prick) - safer to lab technician • Same-day screening and confirmation of results (available <30 min.) Advantages of ‘Same Day’ Rapid Test Results Lower client travel time and expenses Less anxiety during waiting period More likely to get same counselor for both pre- and post-test counseling Client post-test adherence increases dramatically (99+% compared to 60-80%) Client VCT intake increases dramatically (500% in Malawi VCT centers, 1999-2000)* Facilitates expansion of VCT services in resource- constrained settings (remote areas, mobile clinics, etc.) *Msowoya K, Marum E et al. Rapid testing and same day counseling results in huge increase in demand for for VCT in Malawi. International AIDS Conference Abstract Durban, 2000. HIV Rapid Test Algorithm Development (ANNEXE C) Use multiple (up to 3) rapid test kits in parallel or in series to maximize positive and negative prediction values (required for diagnostic purposes) Parallel testing: Clients are tested using two test simultaneously (in parallel) - if tests discordant (<1% occurrence) than a 3rd type of rapid test is used (“tiebreaker”) Serial testing: Clients test with one rapid test. If result is positive, a 2nd different rapid test used. Discordant test results are further tested with 3rd different type of rapid test (tests done in series) Advantages of Parallel (vs. Serial) Testing Algorithm* Minimize the risk of false negative test result Clients perceive that two tests are better than one - reduces client ‘shopping around’ phenomenon Can do two rapid tests with one finger-stick reduces potential stigma that might result if patient called back a second time) Shorter clinic waiting times resulting from simultaneous testing Disadvantage: Parallel testing more expensive b/c using at least two tests for each client *Adapted from: FHI, 2001. Issues in diagnostics for VCT - ‘Focus on’ series. HIV Rapid Test Algorithm Development (cont.) First ‘screening’ rapid test should be as sensitive as possible (minimize false negatives) Follow-up ‘confirmatory’ tests need to be highly specific (minimize false positives) Use ‘Level 1 complexity’ test kits* - require little to no laboratory experience or additional equipment and only finger-prick blood Selected test kits should be recommended by UNAIDS/WHO (see ‘Report of Operational Characteristics of Commercially Available HIV Tests’) *e.g., Determine, Uni-Gold, HemaStrip and Oraquick General Outline for Country Evaluation of HIV Testing Technologies Phase I: Retrospective evaluation of the sensitivity and specificity of selected tests at the national reference laboratory Phase II: Prospective evaluation of the selected tests at the regional laboratories Phase III: Prospective evaluation of selected tests at settings where they will most likely be used NOTE: Outline should be adapted upon for specific country evaluations *UNAIDS/WHO/CDC. 2001. Guidelines for Using HIV Testing Technologies in Surveillance. VCT Clinic Rapid Test QA/QC* Ongoing External Quality Control Proficiency Testing • Every month, random 5-10% of total sample load (ideally including +ve and -ve test results) sent to reference laboratory for ELISA testing cross-checking • All rapid test kit algorithm ‘indeterminate’ results confirmed with ELISA testing before results provided to client Critical Issues for Rapid Test QA/QC* • Use of test kits that have not expired • Training with the technology being used • Adherence to manufacturer’s instructions • Correct interpretation and transcription of results by person reading results *UNAIDS/WHO/CDC. 2001. Guidelines for Using HIV Testing Technologies in Surveillance. PSI Procurement of RTKs: • Approved List of Product Source Manufacturer Country Testing Kit Bioline South Korea Standard Diagnostics Products and Bionor Norway Bionor A/S Capillus Ireland Trinity Biotech* Manufacturers as Determine Japan Abbott Laboratories* of July 6, 2005 DoubleCheck Israel Orgenics First Response India Premier Medical Corporation • 12 Highlighted Genie II France BioRad manufacturers Hema-Strip Singapore Saliva Diagnostic Systems, Ltd.* HIVSav 1&2 Israel Sayvon Diagnostics Ltd. make tests that Immunocomb Israel Orgenics PSI countries Instant Screen Germany GAIFAR GmbH procure from InstantCHEK USA EY Laboratories OraQuick Singapore OraSure Technologies PSI/W SeroCard Ireland Trinity Biotech* Sero-Strip Israel Saliva Diagnostic Systems, Ltd.* Stat-Pack USA ChemBio Diagnostics, Inc. SureCheck HIV USA ChemBio Diagnostics, Inc. Unigold Ireland Trinity Biotech * Parent Company is a United States based firm PSI PROCUREMENT COUNTRIES AND TEST MANUFACTURERS • BENIN- ABBOTT, TRINITY (UNIGOLD) AND ORGENICS • GUYANA- ABBOTT, TRINITY, CHEMBIO, SALIVA • HONDURAS- ORASURE • COTE D’IVOIRE- ABBOTT, PREMIER MEDICAL CORPORATION, TRINITY BIO • KOSOVO- ABBOTT • LESOTHO- ABBOTT, ORGENICS, TRINITY BIO-TECH • MALI- ABBOTT, ORASURE, SALIVA DIAGNOSTICS AND CHEMBIO • MOZAMBIQUE- ABBOTT, TRINITY • TOGO- ABBOTT AND ORGENICS • UGANDA- ABBOTT, CARRAMORE, CHEMBIO AND TRINITY BIO-TECH • WCA AMBASSADOR FUND- ABBOTT, ORGENICS • WEST AFRICA REGION- ABBOTT, ORGENICS, TRINITY • ZAMBIA- ABBOTT, BIORAD, TRINITY • 12/13 use Abbott Determine RTKs, all other VCT countries do as well Questions? See H Drive: AIDSMark: Read Only: VCT: RTK and Lab for more information….
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