Investigation of False Positive Results with an Oral Fluid Rapid HIV-1/2 Antibody Test

Krishna Jafa,Pragna Patel,Tracy L Sides,Duncan A Mackellar,Evan M Cadoff,Bernard M Branson,Alexandra P Newman,Kevin P Delaney,Eugene G Martin,For The Oraquick Study Group ,Sindy M Paul,Patrick A Keenan,Patrick S Sullivan

doi:10.1371/journal.pone.0000185

Abstract

BackgroundIn March 2004, the OraQuick® rapid HIV antibody test became the first rapid HIV test approved by the US Food and Drug Administration for use on oral fluid specimens. Test results are available in 20 minutes, and the oral fluid test is non-invasive. From August 2004–June 2005, we investigated a sudden increase in false-positive results occurring in a performance study of OraQuick® oral-fluid rapid HIV tests in Minnesota.Methodology/Principal FindingsIn a field investigation, we reviewed performance study data on oral-fluid and whole-blood OraQuick® rapid HIV test device lots and expiration dates and assessed test performance and interpretation with oral-fluid and whole-blood specimens by operators who reported false-positive results. We used multivariate logistic regression to evaluate client demographic and risk characteristics associated with false-positive results. Next, we conducted an incidence study of false-positive OraQuick rapid HIV tests in nine US cities and tested both oral-fluid and finger-stick whole-blood specimens from clients; reactive tests were confirmed with Western blot. Sixteen (4.1%) false-positive oral-fluid results occurred in the performance study from April 15, 2004 through August 31, 2004 with unexpired devices from six test lots among 388 HIV-uninfected clients (specificity, 95.9%; 95% CI: 93.4–97.6). Three test operators who had reported false-positive results performed and interpreted the test according to package-insert instructions. In multivariate analysis, only older age was significantly associated with false-positive results (adjusted odds ratio = 4.5, 95% CI: 1.2–25.7). In the incidence study, all valid oral-fluid and whole-blood results from 2,268 clients were concordant and no false-positive results occurred (100% specificity).Conclusions/SignificanceThe field investigation did not identify a cause for the increase in false-positive oral-fluid results, and the incidence study detected no false-positive results. The findings suggest this was an isolated cluster; the test's overall performance was as specified by the manufacturer.

Highlights

In March 2004, the OraQuickH rapid HIV-1 antibody test (Orasure Technologies, Bethlehem, Pennsylvania, USA) became the first rapid Human Immunodeficiency Virus (HIV) test approved by the US Food and Drug Administration (FDA) for use on oral fluid specimens
In this paper we report on: (1) a field investigation to evaluate false-positive device characteristics, to assess test operator practices, and to retrospectively evaluate performance study client characteristics associated with false-positive test results; and (2) an incidence study of false-positive OraQuick test results to prospectively evaluate client characteristics associated with falsepositive test results and device characteristics including test-line intensity and color
From April 15, 2004 through August 31, 2004, 16 (4.1%) false-positive oral-fluid OraQuick results occurred with test devices from six different lots among 388 HIV-uninfected clients (Fig. 1)

Summary

Introduction

In March 2004, the OraQuickH rapid HIV-1 antibody test (Orasure Technologies, Bethlehem, Pennsylvania, USA) became the first rapid Human Immunodeficiency Virus (HIV) test approved by the US Food and Drug Administration (FDA) for use on oral fluid specimens. From August 2004–June 2005, we investigated a sudden increase in false-positive results occurring in a performance study of OraQuickH oral-fluid rapid HIV tests in Minnesota. We conducted an incidence study of false-positive OraQuick rapid HIV tests in nine US cities and tested both oral-fluid and finger-stick whole-blood specimens from clients; reactive tests were confirmed with Western blot. Sixteen (4.1%) false-positive oral-fluid results occurred in the performance study from April 15, 2004 through August 31, 2004 with unexpired devices from six test lots among 388 HIV-uninfected clients (specificity, 95.9%; 95% CI: 93.4–97.6). The field investigation did not identify a cause for the increase in false-positive oral-fluid results, and the incidence study detected no false-positive results The findings suggest this was an isolated cluster; the test’s overall performance was as specified by the manufacturer

Methods

Results

Conclusion