Poster #2
HIV Diagnostics Meeting
March 2005
Orlando, Florida
CLINICAL TRIAL OF THE HEMA-STRIP HIV RAPID TEST USING FINGERSTICK BLOOD,
WHOLE BLOOD, PLASMA, AND SERUM
Niel T. Constantine1, Dan Bigg2, Daniel Cohen3, Joanne Court4, Alison Jones5, Fassil Ketema1, Thomas Koppes6, Vincent Marsiglia7, Harry Prince8
1University
5Tapestry
of Maryland, Baltimore, MD, 2Chicago Recovery Alliance, Chicago, IL, 3Fenway Community Health, Boston, MA, 4MDC Associates, Boston, MA,
Health Services, Northhampton, MA, 6Northstar Medical Center Chicago, IL, 7BDC Laboratory, Baltimore, MD, 8Focus Technologies, Cypress, CA
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Backgroundhere
HIV tests are indispensable for providing results in a clinically-relevant time frame for
occupational exposures and women in labor without known HIV status, and in public
health clinics to maximize the reporting of results to subjects in a timely manner to
minimize the effects of loss to follow up. Moreover, it is increasingly becoming
important, especially in developing nations where resources are scarce, that
alternate sample matrices/media (such as fingerstick whole blood and saliva
samples) be available for testing by HIV assays.
RESULTS
Of the 1515 samples tested, 947 were classified by the reference test(s) as being from
non-infected subjects, and 568 were from infected persons.
Site summary with participant populations (n=1,515)
Site
Maryland
Illinois
Texas
Massachusettes
Total
LR = Low Risk,
Objectives
To evaluate the performance characteristics of a novel rapid HIV test in a large number
of persons from
several populations
To determine the concordance of results when using several different blood matrices.
RESULTS
LR
HR
Pos
200
201
199
0
190
193
156
0
0
148
120
108
504
511
500
HR = High Risk, Pos = Positive
Total
600
383
156
376
1515
The positive and negative predictive values among all populations were estimated at 99.8% and
99.7%, respectively. The sensitivities for the different blood matrices were between 99.5 and
99.7%, and the specificities were all 99.9%. Only one site produced sensitivity values below
99%, and all sites produced specificity values above 99.1%.
Overall Performance Characteristics (n=1,515) - Positive and Negative Predictive Value
Fingerstick
Whole Blood
Plasma
Serum
The Hema-Strip HIV test correctly identified 1513 of the 1515 samples producing
566 positive results and 949 negative results. Overall, there were 3 false negatives
and 1 false positive. This resulted in an overall sensitivity of 99.5% (95% CI: 99.4,
100) and an overall specificity of 99.9% (95% CI: 99.4, 100), thereby exceeding the
98% lower bounds of acceptable performance.
Overall Performance Characteristics (n=1,515) - Sensitivity and Specificity
Matrix
Overall
Sites:
Seven sites from 4 states (Maryland, Illinois, Massachusetts, and Texas) were
selected to enroll study participants for the evaluation of the rapid test. Prior to their
participation in the study, participants signed consent forms approved by the Institutional
Review Board at the respective study sites.
Samples:
A total of 1,515 participants were enrolled and tested in this evaluation and
included 504 at low risk for HIV, 511 at high risk, and 500 persons known to be infected with
HIV. Fingerstick whole blood, venous whole blood, plasma, and serum sample sets were
collected from each participant and tested by the Hema-Strip HIV test, and results were
compared to FDA approved reference tests.
Rapid and Reference Tests:
The Hema-Strip HIV (SDS, Beverly, MA) is a rapid, onestep, lateral flow immunoassay that incorporates a protein A colloidal gold conjugate, includes
a procedural control, and provides results within 15 minutes. The reference assays included
the Abbott HIVAB HIV-1/HIV-2 (rDNA) EIA Kit (Abbott Laboratories, Abbott Park, IL), the
Genetic Systems HIV Types 1 and 2 (recombinant and synthetic peptide) EIA, (Bio-Rad
Laboratories, Redmond, WA), Genetic Systems HIV-1 Western blot (Bio-Rad Laboratories,
Redmond, WA), and the Roche Amplicor HIV-1 Monitor Test (version 1.5) (Roche,
Indianapolis, IN).
Fingerstick
Whole Blood
Plasma
Serum
Matrix
Serum samples from each participant were tested by the Abbott HIV 1/2 EIA
and the Hema-Strip HIV test. Samples initially reactive by EIA or the Hema-Strip HIV test were
repeated in duplicate by the same assay. Western Blots were performed on specimens
exhibiting a repeatedly reactive Abbott EIA and/or a reactive result on the Hema-Strip HIV test.
Western Blots were not performed on samples from known HIV Positive participants as long as
the EIA was reactive. Bio-Rad Genetic Systems HIV-1/2 EIA testing (in triplicate) and the
Roche Amplicor NAT were performed on all discordant samples for resolution.
99.7%
99.5%
99.5%
99.5%
(566 / 568)
(565 / 568)
(565 / 568)
(565 / 568)
98.7, 100.0
98.5, 99.9
98.5, 99.9
98.5, 99.9
99.9%
99.9%
99.9%
99.9%
(946 / 947)
(946 / 947)
(946 / 947)
(946 / 947)
99.4, 100.0
99.4, 100.0
99.4, 100.0
99.4, 100.0
Performance Characteristics by Population – Low Risk - Sensitivity and
Specificity
Matrix
Overall
Fingerstick
Whole Blood
Plasma
Serum
Sensitivity Estimate
Specificity Estimate
Sensitivity 95% CI
Specificity 95% CI
(# detected / # HIV +)
(# undetected / # HIV --)
0.0% (0 / 1)
0.0, 97.5
99.8% (502 / 503)
98.9, 100.0
0.0%
0.0%
0.0%
0.0%
(0 / 1)
(0 / 1)
(0 / 1)
(0 / 1)
0.0, 97.5
0.0, 97.5
0.0, 97.5
0.0, 97.5
99.8%
99.8%
99.8%
99.8%
(502 / 503)
(502 / 503)
(502 / 503)
(502 / 503)
98.9, 100.0
98.9, 100.0
98.9, 100.0
98.9, 100.0
Sensitivity Estimate
Specificity Estimate
Sensitivity 95% CI
Specificity 95% CI
(# detected / # HIV +)
(# undetected / # HIV --)
98.5% (66 / 67)
92.0, 100.0
100.0% (444 / 444)
99.2, 100.0
98.5%
98.5%
98.5%
98.5%
(66 / 67)
(66 / 67)
(66 / 67)
(66 / 67)
92.0, 100.0
92.0, 100.0
92.0, 100.0
92.0, 100.0
100.0%
100.0%
100.0%
100.0%
(444 / 444)
(444 / 444)
(444 / 444)
(444 / 444)
99.0, 100.0
99.0, 100.0
99.0, 100.0
99.0, 100.0
99.8%
99.7%
99.7%
99.7%
(946 / 948)
(946 / 949)
(946 / 949)
(946 / 949)
NPV 95% CI
99.1, 99.9
99.2, 100.0
99.1, 99.9
99.1, 99.9
99.1, 99.9
0.0%
0.0%
0.0%
0.0%
PPV 95% CI
(0 / 1)
(0 / 1)
(0 / 1)
(0 / 1)
0.0, 97.5
0.0, 97.5
0.0, 97.5
0.0, 97.5
0.0, 97.5
NPV Estimate
(# HIV -- / # undetected)
99.8% (502 / 503)
99.8%
99.8%
99.8%
99.8%
(502 / 503)
(502 / 503)
(502 / 503)
(502 / 503)
NPV 95% CI
98.9, 100.0
98.9, 100.0
98.9, 100.0
98.9, 100.0
98.9, 100.0
Performance Characteristics by Population – High Risk - Positive and Negative Predictive
Value
Overall
Fingerstick
Whole Blood
Plasma
Serum
Matrix
Fingerstick
Whole Blood
Plasma
Serum
99.0, 100.0
PPV Estimate
(# HIV + / # detected)
100.0% (66 / 66)
100.0%
100.0%
100.0%
100.0%
(66 / 66)
(66 / 66)
(66 / 66)
(66 / 66)
PPV 95% CI
94.6, 100.0
94.6, 100.0
94.6, 100.0
94.6, 100.0
94.6, 100.0
NPV Estimate
(# HIV -- / # undetected)
99.8% (444 / 445)
99.8%
99.8%
99.8%
99.8%
NPV 95% CI
98.8, 100.0
(444 / 445)
(444 / 445)
(444 / 445)
(444 / 445)
98.8, 100.0
98.8, 100.0
98.8, 100.0
98.8, 100.0
Performance Characteristics by Population – Known HIV Positive - Positive and Negative Predictive
Value
Performance Characteristics by Population – High Risk - Sensitivity and
Specificity
Matrix
(566 / 567)
(565 / 566)
(565 / 566)
(565 / 566)
PPV Estimate
(# HIV + / # detected)
0.0% (0 / 1)
Fingerstick
Whole Blood
Plasma
Serum
Matrix
Overall
Algorithm:
Sensitivity Estimate
Specificity Estimate
Sensitivity 95% CI
Specificity 95% CI
(# detected / # HIV +)
(# undetected / # HIV --)
99.5% (565 / 568)
98.5, 99.9
99.9% (946 / 947)
99.4, 100.0
99.8%
99.8%
99.8%
99.8%
NPV Estimate
(# HIV -- / # undetected)
99.7% (946 / 949)
PPV 95% CI
Performance Characteristics by Population – Low Risk - Positive and Negative Predictive Value
Overall
Methods
PPV Estimate
(# HIV + / # detected)
99.8% (565 / 566)
Matrix
Overall
Overall
Fingerstick
Whole Blood
Plasma
Serum
PPV Estimate
(# HIV + / # detected)
100.0% (499 / 499)
100.0%
100.0%
100.0%
100.0%
(500 / 500)
(499 / 499)
(499 / 499)
(499 / 499)
PPV 95% CI
99.3, 100.0
99.3, 100.0
99.3, 100.0
99.3, 100.0
99.3, 100.0
NPV Estimate
(# HIV -- / # undetected)
0.0% (0 / 1)
0.0%
0.0%
0.0%
0.0%
(0 / 0)
(0 / 1)
(0 / 1)
(0 / 1)
NPV 95% CI
0.0, 97.5
0.0, 0.0
0.0, 97.5
0.0, 97.5
0.0, 97.5
99.2, 100.0
99.2, 100.0
99.2, 100.0
99.2, 100.0
Performance Characteristics by Population – Known HIV Positive - Sensitivity and Specificity
Conclusion
Interpretation of Results:
Sensitivity, specificity, and positive and negative predictive
values of the Hema-Strip HIV test were determined for each of the 4 sample matrices. Overall,
the sensitivity was based on 568 (37%) true HIV positive samples and the specificity was
based on 947 (63%) true negative samples. All statistical tests were performed in StatXact,
and 95% confidence intervals were also calculated for the performance characteristics of the
Hema-Strip HIV test.
Overall
Sensitivity Estimate
(# detected / # HIV +)
99.8% (499 / 500)
Fingerstick
Whole Blood
Plasma
Serum
100.0% (500 / 500)
99.8% (499 / 500)
99.8% (499 / 500)
99.8% (499 / 500)
Matrix
Sensitivity 95% CI
98.9, 100.0
99.3, 100.0
98.9, 100.0
98.9, 100.0
98.9, 100.0
Specificity Estimate
Specificity 95% CI
(# undetected / # HIV --)
0.0% (0 / 0)
0.0, 0.0
0.0%
0.0%
0.0%
0.0%
(0 / 0)
(0 / 0)
(0 / 0)
(0 / 0)
0.0, 0.0
0.0, 0.0
0.0, 0.0
0.0, 0.0
The Hema-strip HIV test has exhibited excellent performance characteristics when evaluated at multiple
sites and using four blood matrices. The test meets expectations for use in low risk, high risk, and HIV
positive populations. The Hema-Strip HIV test is simple to perform, requires minimal procedural steps,
and is suitable for point of care testing applications. It is currently pending FDA PMA approval.