Transcript Slide 1

Can a second rapid HIV test
discriminate false positives
as effectively as a Western Blot?
The NJ Experience
Cadoff EM, Cadoff RA, Salaru G, Paul SM, Martin EG
Evan M. Cadoff, MD
Robert Wood Johnson Medical School
New Brunswick, NJ
NJHIV Rapid Testing Program
UMDNJ-RWJMS/ NJ DHSS
AIDS PREVENTION GRANTEES
Primary
Satellite fixed
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mobile
Pale colors indicate pending sites
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AIDS Coalition of Southern New Jersey
Atlantic City Health Department
Bergen County Health Department
Burlington County Health Department
Camden AHEC
Camden County Health Department
Check-Mate
East Orange Health Department
Eric B. Chandler Health Center
FamCare
Henry J. Austin Health Center
Hope House
Horizon Health Center
Hunterdon County Health Department
Hyacinth Foundation
Institute For Human Development
Jersey Shore Addiction Services
Lennard Clinic
Martin Luther King Outreach
Newark Community Health Center
New Horizon Treatment Services
NJCRI
Ocean County Health Department
Paterson Health Department
Plainfield Community Health Center
Proceed
Robert Wood Johnson Medical School
William Paterson College
12/2/2007
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Under direction of RWJMS
OraQuick started November
1, 2003
Oversees about 2/3 of NJ
CTS HIV testing
Confirmatory testing at PHEL
in Trenton
NJHIV oversees followup of
all discordant
NJHIV does not evaluate
linkage to care
Preliminary Positive Followup
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7.1% refused blood draw for confirmation
25.8% of those drawn did not return for
results
70.1% of confirmed positives got their
results and post-test counseling
Rapid confirmation could improve
effectiveness of prevention and
referral/entry to care and treatment services
Data Needs for
Proposed Testing Strategies
1. Are there false negative screening tests?
2. Can true positive screening tests be confirmed by a
second rapid test, rather than WB/IFA/NAT?
3. Can false positive screening tests (ie discordants) be
detected by a second rapid test, rather than waiting
for WB/IFA/NAT?
4. Impact on linkage to care?
5. How well can inconclusive “second-round” test
results (eg, WB vs a second rapid test) be resolved?
Two NJHIV Datasets
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Confirm true positives
Evaluate confirmed false positives
Resolve discordants and indeterminate
confirmatory test results
Nov 2003 – April 2005 data
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Rapid testing by blood only using OraQuick
Western Blot specimens sent to PHEL
All avialable WB specimens evaluated by:
 Repeat OraQuick on blood
 Trinity Uni-Gold
 MedMira Reveal
 BioRad Multispot
Followup of clients with discordant results
Nov 2003 – April 2005 data
15,923 OraQuick tests statewide
 363 preliminary postive samples
to state lab for Western Blot
 355 Western Blot positive
confirmed by other rapids
 8 Western Blot negative
discordants
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all repeat OraQuick positive
 one reactive Multispot by one reader
 others all negative
 6 preliminary positive is false positive
 25% with no clinical followup
8
15,923
355
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Negative
Discordant
WB Pos
Strategy 1, Data Need 3
Discordant followup
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Four visits:
1. Rapid test. If prelim pos, draw blood and
send to Trenton for Western Blot.
2. Return in a week, and get discordant
confirmatory test result.
3. Return at a month to have more blood
drawn (repeat antibody; and NAAT).
4. Come back a week later for definitive
result.
Discordant followup
Symptoms
Antibody
by 1st gen EIA
Antibody
by Western Blot
Antibody
by 3rd gen EIA
Antigen
RNA / NAAT
Acute Infection
Silent Infection
AIDS
Weeks after infection
5-10 years
1-3 years
Revised discordant followup
Three Visits
1. If rapid test is reactive, draw Western Blot.
2. Return in a week. Get discordant
confirmatory test result and draw NAAT.
3. Third visit for NAAT result.
or
Two Visits
1. If rapid test is reactive, draw both Western
Blot and NAAT.
2. NAAT is run if WB is discordant, and both
results are available at second visit.
Revised discordant followup
Three Visits
1. If rapid test is reactive, draw Western Blot.
2. Return in a week. Get discordant
confirmatory test result and draw NAAT.
3. Third visit for NAAT result.
or
Two Visits
1. If rapid test is reactive, draw both Western
Blot and NAAT.
2. NAAT is run if WB is discordant, and both
results are available at second visit.
or
One visit with rapid confirmation would be better!
Jan 2006 – Oct 2007 data
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Retained specimens from followup
testing for discordant Western Blot
results.
Cannot confirm true positives.
Can evaluate discordants and
indeterminates (if they had followup).
Jan 2006 – Oct 2007 data
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Samples are not from the same time as
screening OraQuick.
Used CLIA-waived tests:
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Repeat OraQuick on blood
Trinity Uni-Gold
Clearview StatPak
Jan 2006 – Oct 2007 data
Total tests, NJ 2006-2007
1535
Total tests
Confirmed positive
119794
72
41
No followup
No blood available
Other rapids tested
67
180 discordant
108 false positive; 72 without followup may be false positive
No false positive strategy results [Strategy 4,Data need 1];
No false negative A2 or A3 [Strategy 4, Data need 4, 5b]
[Strategy 1, Data need 3; Strategy 4, Data need 5a]
Jan 2006 – Oct 2007 data
Oral screening, NJ 2006-2007
892
Total tests
Confirmed positive
77592
65
35
No followup
No blood available
Other rapids tested
56
156 discordant
No false positive strategy results [Strategy 3, Data need 1]
1 false positive A1-blood result [Strategy 3, Data need 4a,5]
91 false positive A1-oral results [Strategy 3, Data need 5]
No false negative A2 results [Strategy 3, Data need 4b]
Jan 2006 – Oct 2007 data
Blood screening, NJ 2006-2007
643
Total tests
7
42202
6
Confirmed positive
No followup
No blood available
Other rapids tested
11
24 discordant
No false positive strategy results [Strategy 2, Data need 1]
17 Inconclusive results with false positive A1 [Strategy 2, Data need 4]
Data Needs for
Proposed Testing Strategies
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All followups on negative Western Blot were NAAT
negative (OraQuick false positive).
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All were "second rapid" negative.
Oral OraQuick followed by blood OraQuick:
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3 tested at CTS site on False Positives:
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56 tested on followup blood specimen
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2 blood negative; 1 blood positive
all blood negative
OraQuick blood discordant
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11 tested on followup blood specimen
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7 negative
4 repeat positive
Observations
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Indeterminate Western Blot:
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12 total:
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4 no followup; 3 QNS
3 NAAT negative were "second rapid" negative
2 NAAT positive were "second rapid" positive
Rapid Confirmation Is Needed
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Rapid confirmation of preliminary
positive results is necessary:
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30-40% without followup would have
benefited from rapid confirmatory testing.
Rapid Confirmation Works
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All 355 true positives confirmed using a
second rapid test (from a pool of about 16,000 clients
tested)
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All 65 false positives with followup available
were negative using a second rapid test (from a
pool of about 120,000 clients tested)
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Indeterminate Western Blots were resolved by
a second rapid
Conclusions
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Rapid confirmation of preliminary
positive results is necessary.
Rapid confirmation of preliminary
positive results works at least as well as
Western Blot testing.