Dried blood spot HIV testing

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

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

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’)


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


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


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


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


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

Adapted from McMichael AJ etal Nature Rev Immuno 2010L

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Relative sensitivity (Acute HIV)

Sensitivity (%)

100 90 80 70 60 50 40

Dried blood spot HIV testing

Health & Medicine

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