Transcript view PowerPoint - 2016 HIV Diagnostics Conference

The Use of Additional Rapid HIV Tests on
Whole-Blood Increases the Predictive
Value of Rapid Oral Fluid Testing
Alicia N. Scribner, MPH, Douglas A.E. White, MD
December 6, 2007
2007 HIV Diagnostics Conference
Background
• CDC guidelines recommend screening for HIV
in health care settings
• Oral fluid testing benefits
– Ease of performance
– Patient acceptance
• Oral fluid has lower specificity than blood
testing
– Oral 99.8% (99.6%-99.9%)
– Blood 100% (99.7%-100%)
OraQuick
ADVANCED® HIV 1/2
• Need for rapid testing algorithm to confirm
positive results
Objective
To distinguish true positive results from
false positive results at time of testing
To determine a practical testing algorithm
for use with point of care testing (POC)
Methods: Study Setting
• Highland Hospital ED, Oakland, CA
– Urban, academic ED
– Regional Trauma Center
• Predominantly minority population
– 47% Black
– 32% Hispanic
• Low SES
– 53% of ED patients do not have health
insurance.
Methods: HIV Screening Protocol
• HIV Testers stationed in
ambulatory triage
• Routinely offered and
performed HIV testing on
eligible patients
Medical Assistants
M-F 6:30AM – 8:30PM
–
–
–
–
≥ 15 years old
Normal mental status
Not acutely ill
Not recently tested
• Test results disclosed at
the patient bedside
Feb 1, 2007-Sep 30, 2007
Methods: Protocol
Preliminary Positive
OraQuick ADVANCE® HIV 1/2 (OQA)
Oral Fluid
Western
Blot (WB)
Testing
Unigold™
Recombigen®
Clearview® HIV
1/2 Stat-Pak®
OraQuick
Advance® HIV
1/2
Using Whole Blood
Methods: PP Pathway
Preliminary Positive Result Counseling and Recommended Dialogue: Your oral rapid
test came back preliminary positive. This usually means that you are infected with HIV.
However, this test can sometimes produce a false positive result, so we’d like to do a
second test, to see if we get the same result. Either way we would like to draw blood
and send it to our lab for confirmation – but this extra test will give us more information
about whether it is likely that you have HIV.
Complete additional rapid tests
1) OraQuick
2) Stat-Pak
3) Uni-Gold
Any rapid blood test positive?
No
Use the Discordant Handout (yellow sheet)
and counsel patient. Be sure the front page
of the survey has an accurate phone
number for conducting follow-up.
Yes
Follow preliminary positive disclosure
protocol. Use the Preliminary Positive
Physician Instructions (blue sheet).
DISCORDANT PRELIMINARY HIV TESTS
Although the first test we ran today was preliminary positive, we
ran different rapid tests afterward to confirm this and they were
negative. Based on that, it’s very likely that you don’t have HIV.
The first thing we need to do is to find out which test result is
correct.
We will send that vial of blood we drew to an off-site lab for
further confirmation, and if any HIV antibodies are detected, we
will contact you as soon as we know. But, if as expected the results
are negative, we won’t contact you. If you would like, you’re
welcome to call us to follow up after two weeks, when the results
will be ready. Our phone number is (510) 437-8378. Before you
leave today, make sure you give us the best phone number to reach
you at.
Results
7,340 persons tested for HIV using OQA on oral fluid
51 (0.7%) reactive tests
38 (75%)
had concordant
reactive rapid test
results on whole blood
12 (24%)
additional rapid tests
were non-reactive
All 38 were confirmed 10 were WB 2 were WB
WB positive
indeterminate negative
1 (2%)
additional rapid
tests were
discordant
Indeterminate
WB
Results: Discordant Oral and Blood
Rapid Tests
OraQuick
Oral
OraQuick
Blood
UniGold
Stat-Pak
Western
Blot
IFA
Patient 1
PP
N
N
N
I
N
Patient 2
PP
N
N
N
I
N
Patient 3
PP
N
N
N
I
N
Patient 4
PP
N
N
N
N
-
Patient 5
PP
N
N
N
I
N
Patient 6
PP
N
N
N
I
N
Patient 7
PP
N
N
N
I
N
Patient 8
PP
N
N
N
I
In
Patient 9
PP
N
N
N
I
N
Patient 10
PP
N
N
N
I
N
Patient 11
PP
N
N
N
I
N
Patient 12
PP
N
N
N
N
-
Patient 13
PP
PP
N
PP
I
N
Abbreviations: PP is preliminary positive; N is non-reactive; I is indeterminate, In is inconclusive
Results: WB Patterns
17
24
31
41
51
55
66
120
160
Patient 1
A
A
A
A
A
A
A
A
A
Patient 2
A
I
A
P
A
A
A
A
A
Patient 3
P
A
A
P
A
A
A
A
A
Patient 5
A
A
A
A
I
A
P
A
A
Patient 6
A
A
A
A
A
I
A
A
A
Patient 7
A
A
A
A
A
P
A
A
A
Patient 8
A
I
A
A
A
A
A
A
A
Patient 9
I
A
A
A
A
I
I
A
A
Patient 10
I
A
A
A
A
I
I
A
A
Patient 11
A
P
A
A
I
A
I
A
A
Patient 13
A
A
A
A
A
P
A
A
A
Abbreviations: A is absent, P is present, I is indeterminate
Results: Follow-Up Testing
All 13 patients were contacted for follow-up testing at three months
3 months:
Patient 13: EIA non-reactive, VL 3,240 copies/mL
6 months:
OraQuick
Oral
OraQuick
Blood
UniGold
Stat-Pak
Western
Blot
IFA
Patient 7
N
-
-
-
-
-
Patient 9
N
N
N
N
I
pending
Conclusions: Clinical Observations
• All 13 false positive
patients had
qualitatively
different test lines
• Faint
• Grey
Conclusions: Likely false positives
Preliminary Result Counseling and Recommended Dialogue: The test device did not give
very clear results - sometimes this happens with the oral swab. I recommend repeating
the test with a blood sample - this additional test will give us more information about your
HIV status. I will perform the test now and we will have the results in about 30 minutes.
Obtain Invalid T Zone envelope.
Complete additional rapid tests
1) OraQuick
2) Stat-Pak
3) Uni-Gold
Any rapid blood test positive?
No
Use the Negative Handout (pink
sheet) and counsel patient. Be sure
the front page of the survey has an
accurate phone number.
Yes
Follow preliminary positive disclosure
protocol
Use the Preliminary Positive Physician
Instructions (blue sheet).
Conclusions: Positive Predictive Values
• OQA with oral fluid:
38/51 = 0.75
• OQA with oral fluid + OQA with blood:
38/39 = 0.97
• OQA oral fluid + 3 blood rapid tests: 38/38
= 1.00
Conclusions
• Multiple Rapid Testing (MRT) correctly
identified all true positives
• MRT identified all but one false positive
• Although helpful, MRT is challenging and
difficult to implement for POC testing
• Proposed Solution: confirm oral fluid
reactive tests with a single blood rapid test
– Switch test if using dedicated staff
– PP oral followed by negative blood should be
tested with additional rapid tests
Questions
Alicia Scribner
[email protected]
(510) 437-8354
Douglas White
[email protected]
(510) 535-7439