Transcript Confirmation Algorithm for HIV Rapid Testing

Resolution of Discordant Confirmatory Results on
POC Reactive Rapid Tests: Florida’s Pilot Project
HIV Diagnostics: New Developments and Challenges
Feb. 28, 2005
Berry Bennett, MPH
Retrovirology Section Chief
FL. Bureau of Laboratories
Jacksonville, FL.
Public Health Laboratories (PHL) Role in Rapid HIV
Testing
• Provide Confirmation testing on POC presumptive positive rapid tests.
• Provide quality assurance testing on POC negatives, if applicable?
• Participate in site specific QA programs
- provide technical training needs
- provide blood borne pathogen and biohazard safety training
- provide proficiency samples and/or encourage CDC’s MPEP enrollment.
- provide competency evaluations (site visits?)
- provide verification samples and/or quality controls
• more?? (regulatory consults, troubleshooting, etc.)
In July/August 2004 the Association of Public Health Laboratories (APHL) conducted
a survey of 56 state and territorial PHLs to assess HIV diagnostic testing practices.
The survey included questions as to utilization of rapid tests within PHLs and the
roles that PHLs have played in training for non-traditional testing facilities.
- Approximately 10% of the respondents indicated use of rapid tests (in-house
algorithm vs. study related vs. off-site PHL supported, not specified).
- 45% of PHLs have delivered at least one rapid HIV training course, either their
own design or CDC.
Confirmation Algorithm* for HIV Rapid Testing
POC presumptive positive rapid test
HIV-1 Western blot or IFA (serum, plasma, dbs)(Orasure W.Blot only)
Positive
Negative
Indeterminate
Report as
HIV-1 Positive
Report as
HIV-1 Negative,
request blood
retest.
Report as
HIV-1 Indeterminate,
(blood) advise 30 day
follow up, (Orasure)
request blood retest.
*CDC Guidelines for a Quality Assurance Program,March, 31, 2003.
www.cdc.gov/hiv/rapid_testing
Florida Confirmation Algorithm for HIV Rapid
Testing
POC presumptive positive rapid test
HIV-1 Western blot
(serum, plasma, dbs, Orasure)
Positive
Report as
HIV-1 Positive
possible STARHS case
(except Orasure)
HIV-1/2 Plus O EIA
HIV-1 Orasure EIA
(comparative purposes)
Negative
Indeterminate
HIV-2 testing (serum, plasma)
OraQuick retesting (serum, plasma)
Unigold HIV-1 (comparative purposes)
(serum, plasma)
Expectations in the Confirmation of POC
Presumptive Positive Rapid Tests?
• Provide quick TAT (county jails, drug treatment centers, ERs)
• Adjust traditional testing algorithms to accommodate a quick TAT
• Serum, plasma or dbs are preferred specimens however Orasure may
be the only alternative for some sites.
• Provide additional testing (NAAT, Ag+, etc) or refer to CDC to resolve
discordance between rapid and traditional laboratory results.
Florida Department of Health
OraQuick Pilot Study
(Summer 2003 – Dec. 2004)
POC tests performed = 27,473
POC negative results = 26,695
POC “presumptive positives” = 778
Lab-confirmed positives = 764 (98%)
Initial rapid tests non-confirmed‡ = 14*
Seropositivity rate = 2.78%
‡ Western Blot negative or indeterminate.
*(7) confirmation specimen submitted was unsatisfactory for rapid retesting.
(4) OraQuick negative upon repeat (possible POC user misinterpreted)
(3) OraQuick positive upon repeat (assay false positive)
Discordant Review of POC Presumptive Positive OraQuicks:
Florida, Summer 2003 – 12/31/2004
Confirmation
sample
traditional lab-based
results
lab-based
rapid retesting
oral fluid (7)
HIV-1 EIA r/r (3/7)
HIV-1 W Blot Ind.
N/A
HIV-1 EIA nr (4/7)
HIV-1 W Blot neg. (2)
HIV-1 W Blot Ind. (1)
N/A
serum (7)
other
Unconfirmed reports of
(3) seroconversion
outside PH testing
N/A
HIV-1/2 EIA nr (7/7)
OraQuick pos. (3/7) <75 RNA copies/ml (1)
HIV-1 W Blot neg. (7/7)*
Unigold neg. (3)
HIV-2 EIA nr (7/7)
OraQuick neg. (4/7)
Unigold neg. (3)
Unigold n/a (1)
All cases are being monitored for seroconversion, poor client return rates thus far.
* One individual w/ initial W Blot Ind., negative on redraw
BBI Seroconversion Panel Results:
Member#
PRB958-01
PRB958-02
PRB958-03
PRB958-04
PRB958-05
PRB958-06
days since
1st bleed
0
2
7
9
15
17
G.S.
HIV-1/2
SP
0.1
0.1
0.1
0.1
1.0
2.6
BBI
PRB958-01
02
03
04
05
06
C.B. W Blot
no bands
no bands
no bands
no bands
no bands
no bands
BBI
G.S
HIV-1/2
Plus O
0.25
0.25
0.2
0.2
2.4
11.0
BOL
RT-PCR
2 X 102
2 X 103
2 X 105
5 X 105
4 X 104
>8 X 105
BBI
Unigold
HIV-1r
N
N
N
N
N
wP
BOL
OraQuick
(20) (40)
N
N
N
N
N
N
N
N
N
N
N
N
BOL
BBI Seroconversion Panel Results:
Member#
PRB959-01
PRB959-02
PRB959-03
PRB959-04
PRB959-05
PRB959-06
PRB959-07
days since
1st bleed
0
7
9
14
19
21
26
G.S.
HIV-1/2
SP
0.1
0.1
0.2
1.8
7.3
7.6
7.8
G.S
HIV-1/2
Plus O
0.2
1.0
7.0
13.1
13.1
13.1
13.1
BBI
PRB959-01
02
03
04
05
06
07
BOL
C.B. W Blot
RT-PCR
no bands
no bands
no bands
p24, gp160
p24, gp160
p24, gp160
p24, gp160
2 X 105
>8 X 105
>8 X 105
8 X 105
5 X 105
3 X 105
>8 X 105
BBI
BBI
Unigold
HIV-1r
N
N
N
P
P
P
P
BOL
OraQuick
(20) (40)
N
N
N
N
N
N
P
P
P
P
P
P
P
P
BOL
Florida Lessons Learned (thus far):
• Altering our algorithm has improved rapid confirmation TAT. Is it advisable as numbers
increase and testing sites vary?
• Follow up success on discordant cases is dependant on POC testing site. Ex. Jail
settings are better than some PH clinics.
• Repeating rapid tests in the laboratory, if possible, on POC presumptive positive cases is
a valuable tool in differentiating user vs. assay discordance.
• Sample choice in the confirmation process may limit additional testing needs.
• We clearly have discordance between rapid assays. Need for further investigations!
• We recommend enlisting CDC’s assistance early in the process.