Dr. Kate Templeton SPAIIN –Stirling 2011
Overview HIV Infection Tests used in diagnostic labs How to access them Challenges HIV prevention Non –conformity to existing strategies
Opportunities to Identify HIV Infections Anti-HIV antibody SeroconversionillnessSeroconversionillness Asymptomatic phase Symptomatic phase AIDSAIDS DeathDeath Immunological fitness Years (average) Historic Major Diagnostic Opportunities
List of tests HIV screening test 4 th generation EIA format Includes Antigen as well as Antibody On large automated machines HIV confirmation Blot 2 nd EIA HIV RNA – viral load HIV proviral DNA – used to detect HIV in children <18 months old
Understanding markers during an infection….HIV Slide 5 RNARNA AgAg IgMIgM IgGIgG ‘Quantity’ viral spread local viral growth Weeks post-infection avidity IgG3 DNADNA
daysdays Clonesystem s Detect-HIV v1 Innotest HIV-1/-2 Murex ICE HIV 1+2 Murex ICE HIV 1+2 Earliest HIV detection Biotest HIV 1/2 recombinant Biotest HIV 1/2 recombinant Vironostika HIV Uniform II Ag/Ab Enzygnost HIV Integral Enzygnost HIV Integral VIDAS HIV DUO GENSCREEN PLUS HIV Ag- Ab Architect HIV Ag/Ab Combo Murex HIV Ag/Ab combionation Ortho Ab- capt. ELISAOrtho ELISA Vitros ECi anti-HIV 1/2 Vitros ECi anti-HIV 1/2 Murex HIV 1/2 VK84/85 VK84/85 IMx HIV1/2 III plus IMx HIV1/2 III plus Murex HIV GE94/95Murex GE94/95 AxSYM HIV 1/2 gO Abbott 3rd gen Plus Abbott PasteurGenscreen Version 2 PasteurGenscreen Access HIV 1/2 NEW Access HIV 1/2 NEW Vironostika HIV Uniform II plus O Vironostika Biotest Anti-HIV TETRA ELISA Enzygnost HIV 1/2 plus Enzygnost Understanding Applied to Serological Detection of Primary HIV Infection (35 Seroconversion Panels) Earliest anti-HIV detection
HIV testing Antenatal booking HIV – 4 th gen HBsAg Syphilis IgG Rubella IgG Any HIV screen 4 th gen HIV assay Caution – maternal HIV antibody can be present for months
WHO HIV Strategy III Assay 2- 2 nd EIA A1+ A2 + A1+ A2- Repeat A1 and A2 A1+ A2- Repeat A1 and A2 A1+ A2+ A1+ A2- Assay 3- blot A1+ A2+ A3+ report positive consider indeterminate A1+ A2+ A3- A1+ A2- A3+ A1+ A2- A3- High risk Low risk: negative negative Low prevalenceLow prevalence asymptomaticasymptomatic Low prevalenceLow prevalence asymptomaticasymptomatic A1 + Screening EIA A1- report negative A1- A1- A2- report negative A1- A2- report negative
Parry, bioMérieux Symposium, Oct 2006Slide 10 Pat Tookey, Institute of Child Health ZDV monotherapy Antenatal screening roll-out
Slide 11 HIV markers in Perinatally INFECTED child IgG Anti- HIV reacti vity IgG Anti- HIV reacti vity IgA/MAnti-HIVIgA/MAnti-HIV HIV RNA P24 Ag Reactivity‘/ Quantity’ IgA/MAnti-HIVIgA/MAnti-HIV IgG Anti- HIV titre IgG ….12….12…..18…..18 Months post-partum HIV proviral DNA
HIV testing to exclude HIV infection BHIVA/CHIVA guidelines EDTA blood- baby At birth within 1 day 6 weeks ( 2-weeks after stopping Rx) 3 months Need 2 HIV proviral DNA while off therapy Antibody EDTA blood – Mother HIV genetically diverse – check assay integrity against Mothers specific virus. HIV viral load is optional – can give false positives/ or more sensitive Following exposure in genital tract
Summary of testing TimeHIV ProVHIV Ab Baby/Mothe r Samples Required 0-48 hrs (not cord blood) Mother EDTA min 1 ml Baby EDTA min 1 ml 6 weeks** Baby EDTA min 1 ml 12 weeks Baby EDTA min 1 ml months BabyEDTA min 1 ml
HIV proviral DNA testing EDTA samples should be sent need prior telephone notification Specialist Virology Centre Department of Laboratory Medicine Royal Infirmary of Edinburgh 51, Little France Crescent Edinburgh EH16 4SA BBV team can be contacted on Duty Virologist can be contacted on or , bleep 5981
Laboratory processing EDTA blood should be <24 hours old by time in Edinburgh lab – preferably sooner. Keep at room temperature Can arrive: Monday –Friday Saturday – Current turnaround time is 7-10 days Any positive results are phoned to referring clinician
Final point HIV protocol for access to HIV testing to exclude infection in babies should be available via SPAIIN website.