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 of Maryland, Baltimore, MD, 2Chicago Recovery Alliance, Chicago, IL, 3Fenway Community Health, Boston, MA, 4MDC Associates, Boston, MA,5Tapestry Health Services, Northhampton, MA, 6Northstar Medical Center Chicago, IL, 7BDC Laboratory, Baltimore, MD, 8Focus Technologies, Cypress, CA

Insert your information here RESULTS

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.

Methods

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, one-step, 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).

Algorithm: 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.

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.

Conclusion

Background

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.

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.

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.

Site LR HR Pos Total

Maryland 200 201 199 600

Illinois 0 190 193 383

Texas 156 0 0 156

Massachusettes 148 120 108 376

Total 504 511 500 1515

Matrix

Sensitivity Estimate (# detected / # HIV +)

Sensitivity 95% CI Specificity Estimate

(# undetected / # HIV --) Specificity 95% CI

Overall 99.5% (565 / 568) 98.5, 99.9 99.9% (946 / 947) 99.4, 100.0

Fingerstick 99.7% (566 / 568) 98.7, 100.0 99.9% (946 / 947) 99.4, 100.0

Whole Blood 99.5% (565 / 568) 98.5, 99.9 99.9% (946 / 947) 99.4, 100.0

Plasma 99.5% (565 / 568) 98.5, 99.9 99.9% (946 / 947) 99.4, 100.0

Serum 99.5% (565 / 568) 98.5, 99.9 99.9% (946 / 947) 99.4, 100.0

Overall Performance Characteristics (n=1,515) - Sensitivity and Specificity

Site summary with participant populations (n=1,515)

Performance Characteristics by Population – Low Risk - Sensitivity and Specificity

Matrix Sensitivity Estimate

(# detected / # HIV +) Sensitivity 95% CI

Specificity Estimate (# undetected / # HIV --)

Specificity 95% CI

Overall 0.0% (0 / 1) 0.0, 97.5 99.8% (502 / 503) 98.9, 100.0

Fingerstick 0.0% (0 / 1) 0.0, 97.5 99.8% (502 / 503) 98.9, 100.0

Whole Blood 0.0% (0 / 1) 0.0, 97.5 99.8% (502 / 503) 98.9, 100.0

Plasma 0.0% (0 / 1) 0.0, 97.5 99.8% (502 / 503) 98.9, 100.0

Serum 0.0% (0 / 1) 0.0, 97.5 99.8% (502 / 503) 98.9, 100.0

Performance Characteristics by Population – High Risk - Sensitivity and Specificity

Matrix

Sensitivity Estimate (# detected / # HIV +)

Sensitivity 95% CI Specificity Estimate

(# undetected / # HIV --) Specificity 95% CI

Overall 98.5% (66 / 67) 92.0, 100.0 100.0% (444 / 444) 99.2, 100.0

Fingerstick 98.5% (66 / 67) 92.0, 100.0 100.0% (444 / 444) 99.2, 100.0

Whole Blood 98.5% (66 / 67) 92.0, 100.0 100.0% (444 / 444) 99.2, 100.0

Plasma 98.5% (66 / 67) 92.0, 100.0 100.0% (444 / 444) 99.2, 100.0

Serum 98.5% (66 / 67) 92.0, 100.0 100.0% (444 / 444) 99.2, 100.0

Performance Characteristics by Population – Known HIV Positive - Sensitivity and Specificity

Matrix Sensitivity Estimate

(# detected / # HIV +) Sensitivity 95% CI

Specificity Estimate (# undetected / # HIV --)

Specificity 95% CI

Overall 99.8% (499 / 500) 98.9, 100.0 0.0% (0 / 0) 0.0, 0.0

Fingerstick 100.0% (500 / 500) 99.3, 100.0 0.0% (0 / 0) 0.0, 0.0

Whole Blood 99.8% (499 / 500) 98.9, 100.0 0.0% (0 / 0) 0.0, 0.0

Plasma 99.8% (499 / 500) 98.9, 100.0 0.0% (0 / 0) 0.0, 0.0

Serum 99.8% (499 / 500) 98.9, 100.0 0.0% (0 / 0) 0.0, 0.0

RESULTS

Overall Performance Characteristics (n=1,515) - Positive and Negative Predictive Value

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%.

Matrix PPV Estimate

(# HIV + / # detected) PPV 95% CI

NPV Estimate (# HIV -- / # undetected)

NPV 95% CI

Overall 99.8% (565 / 566) 99.0, 100.0 99.7% (946 / 949) 99.1, 99.9

Fingerstick 99.8% (566 / 567) 99.0, 100.0 99.8% (946 / 948) 99.2, 100.0

Whole Blood 99.8% (565 / 566) 99.0, 100.0 99.7% (946 / 949) 99.1, 99.9

Plasma 99.8% (565 / 566) 99.0, 100.0 99.7% (946 / 949) 99.1, 99.9

Serum 99.8% (565 / 566) 99.0, 100.0 99.7% (946 / 949) 99.1, 99.9

Performance Characteristics by Population – Low Risk - Positive and Negative Predictive Value

Matrix PPV Estimate

(# HIV + / # detected) PPV 95% CI

NPV Estimate (# HIV -- / # undetected)

NPV 95% CI

Overall 0.0% (0 / 1) 0.0, 97.5 99.8% (502 / 503) 98.9, 100.0

Fingerstick 0.0% (0 / 1) 0.0, 97.5 99.8% (502 / 503) 98.9, 100.0

Whole Blood 0.0% (0 / 1) 0.0, 97.5 99.8% (502 / 503) 98.9, 100.0

Plasma 0.0% (0 / 1) 0.0, 97.5 99.8% (502 / 503) 98.9, 100.0

Serum 0.0% (0 / 1) 0.0, 97.5 99.8% (502 / 503) 98.9, 100.0

Performance Characteristics by Population – High Risk - Positive and Negative Predictive Value

Matrix

PPV Estimate (# HIV + / # detected)

PPV 95% CI NPV Estimate

(# HIV -- / # undetected) NPV 95% CI

Overall 100.0% (66 / 66) 94.6, 100.0 99.8% (444 / 445) 98.8, 100.0

Fingerstick 100.0% (66 / 66) 94.6, 100.0 99.8% (444 / 445) 98.8, 100.0

Whole Blood 100.0% (66 / 66) 94.6, 100.0 99.8% (444 / 445) 98.8, 100.0

Plasma 100.0% (66 / 66) 94.6, 100.0 99.8% (444 / 445) 98.8, 100.0

Serum 100.0% (66 / 66) 94.6, 100.0 99.8% (444 / 445) 98.8, 100.0

Performance Characteristics by Population – Known HIV Positive - Positive and Negative Predictive Value

Matrix PPV Estimate

(# HIV + / # detected) PPV 95% CI

NPV Estimate (# HIV -- / # undetected)

NPV 95% CI

Overall 100.0% (499 / 499) 99.3, 100.0 0.0% (0 / 1) 0.0, 97.5

Fingerstick 100.0% (500 / 500) 99.3, 100.0 0.0% (0 / 0) 0.0, 0.0

Whole Blood 100.0% (499 / 499) 99.3, 100.0 0.0% (0 / 1) 0.0, 97.5

Plasma 100.0% (499 / 499) 99.3, 100.0 0.0% (0 / 1) 0.0, 97.5

Serum 100.0% (499 / 499) 99.3, 100.0 0.0% (0 / 1) 0.0, 97.5

LR = Low Risk, HR = High Risk, Pos = Positive

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.

Poster #2HIV Diagnostics MeetingMarch 2005Orlando, Florida