HIV Testing and Diagnosis

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HIV Testing and Diagnosis

• Dr. Kate Templeton
• SPAIIN Stirling 2011

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Overview

• HIV Infection
• Tests used in diagnostic labs
• How to access them
• Challenges
• HIV prevention
• Non conformity to existing strategies

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Opportunities to Identify HIV Infections
Asymptomatic phase
Symptomatic phase
AIDS
Seroconversion illness
Death
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List of tests

• HIV screening test
• 4th generation
• EIA format
• Includes Antigen as well as Antibody
• On large automated machines
• HIV confirmation
• Blot
• 2nd EIA
• HIV RNA viral load
• HIV proviral DNA used to detect HIV in children
  lt18 months old

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Understanding markers during an infection.HIV
local viral growth
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Understanding Applied to Serological Detection of
Primary HIV Infection
(35 Seroconversion Panels)
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HIV testing

• Antenatal booking
• HIV 4th gen
• HBsAg
• Syphilis IgG
• Rubella IgG
• Any HIV screen
• 4th gen HIV assay
• Caution maternal HIV antibody can be present
  for 15-24 months

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WHO HIV Strategy III

• Low prevalence
• asymptomatic

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Mother to child transmission
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Pat Tookey, Institute of Child Health
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HIV markers in Perinatally INFECTED child
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(No Transcript)
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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

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Summary of testing
Time HIV ProV HIV Ab Baby/Mother Samples Required
0-48 hrs (not cord blood) ? Mother EDTA min 1 ml
0-48 hrs (not cord blood) ? Baby EDTA min 1 ml
6 weeks ? Baby EDTA min 1 ml
12 weeks ? Baby EDTA min 1 ml
15-18 months ? Baby EDTA min 1 ml
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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 0131 242 7129
• Duty Virologist can be contacted on 0131 242
  6086
• or 0131 536 1000, bleep 5981

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Laboratory processing

• EDTA blood should be lt24 hours old by time in
  Edinburgh lab preferably sooner.
• Keep at room temperature
• Can arrive
• Monday Friday 0900 -2000
• Saturday 0900-1200
• Current turnaround time is 7-10 days
• Any positive results are phoned to referring
  clinician

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Final point

• HIV protocol for access to HIV testing to exclude
  infection in babies should be available via
  SPAIIN website.