This presentation on how dried blood spot testing may overcome some of the barriers to HIV testing was given by Philip Cunningham, NSW State Reference Laboratory for HIV, at the AFAO Members Forum - May 2015.

1. NSW HIV Strategy 2012-2015: A New Era
3.4 Promote HIV testing, making
HIV testing easier to have a test
• Increasing access and increase
frequency
• Remove barriers to testing –
returning for results, cost barriers,
recommended frequency
• Introduce rapid testing
• Reduce late diagnosis of HIV

2. Dried blood spot (DBS)
• Widely used in early infant HIV diagnosis
• Applicable to ‘hard-to-reach’ and remote settings
• Dried samples are stable at room temperature
• Simple transport via post possible
• Self-collection possible
• Conventional lab testing possible
• Seroprevalence surveys for HIV/HCV - ANSPS
• McLaws ML etal. Prevalence of maternal HIV infection
based on anonymous testing of neonates, Sydney 1989.
MJA 1990 Oct 1;153(7):383-6.
Day/Month/Year Footnote to go here Page 2

3. TGA requirements
• Sets out performance criteria and
risk mitigation principles for HIV
tests including PoCT
• Sensitivity: ≥99.5% whole blood, ≥99% oral
fluid
• Specificity: ≥99%
• DBS samples use conventional
laboratory tests (perform within
these specifications)
• Consideration given to detailed
patient information for DBS sample
collection (the ‘kit instructions’)
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9. Day/Month/Year Footnote to go here Page 9

15. Potential benefits
• Conventional HIV antibody laboratory tests possible
• Full confirmation by western blot possible
• HIV DNA/RNA detection possible
• ‘Window period’ same as lab testing
• Access to ‘hard-to-reach’ or remote groups
• Personalizes the sample collection – ‘no immediate test result’
• May appeal to people not wanting to engage with health provider / community
testing settings
• May appeal to other priority populations
? Alternative to venous blood confirmation for PoCT ‘reactives’ ?
TGA approved are available for patient monitoring
• HIV viral tests load possible
• HIV genotypic resistance testing (RNA > 1,000 cpy) possible
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16. Potential drawbacks
• Regulatory – TGA Class 4 IVD - no approved screening tests (4th gen) for DBS
sample type
• How are DBS collection kits distributed
• Non-return rates may be costly (wasted kits)
• DBS not a routine sample type
• Labs not familiar or set up for DBS processing and testing
• Turn around time for results (batched)
• Separates HIV testing from other STI tests – eg bacterial STI and syphilis
• Loss to followup
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17. Costs
DBS collection kit ~ $5.00
Australia Post pre-paid envelope for DBS return ~ $5.46
Processing and testing by conventional lab test - $12.00
For reactive DBS screening test:
HIV western blot $70
HIV DNA PCR = $60
Conventional laboratory tests covered by Medicare or HIV reference laboratory
allocations funding
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18. Evaluation required
• Pilot study being considered NSW
• Broadly target priority populations –
MSM, CALD, sex workers, IDU, people
from endemic countries
• Assess demographics, risk behaviour,
testing history
• Acceptability and feasibility
• Test performance
Day/Month/Year Footnote to go here Page 18
Register
and
consent
online
Receive
DBS kit
Return kit
via post
Central
laboratory
testing
Results
sent to
clinical
service
provider
SMS
results and
clinical
followup

19. Adapted from McMichael AJ etal Nature Rev Immuno 2010
LimitofdetectionforHIVPointofcaretests

20. Relative sensitivity (Acute HIV)
Page 20
Sensitivity (%)
100 90 80 70 60 50 40