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Replacing Clinic-Based Tests With Home-Use Tests May Increase HIV Prevalence Among Seattle Men Who Have Sex With Men: Evidence From a Mathematical Model

Katz, David A. PhD, MPH*; Cassels, Susan L. PhD, MPH†‡; Stekler, Joanne D. MD, MPH*†§

Sexually Transmitted Diseases: January 2014 - Volume 41 - Issue 1 - p 2–9
doi: 10.1097/OLQ.0000000000000046
Original Study

Background Home-use tests have potential to increase HIV testing but may increase the rate of false-negative tests and decrease linkage to HIV care. We sought to estimate the impact of replacing clinic-based testing with home-use tests on HIV prevalence among men who have sex with men (MSM) in Seattle, Washington.

Methods We adapted a deterministic, continuous-time model of HIV transmission dynamics parameterized using a 2003 random digit dial study of Seattle MSM. Test performance was based on the OraQuick In-Home HIV Test (OraSure Technologies, Inc, Bethlehem, PA) for home-use tests and, on an average, of antigen-antibody combination assays and nucleic acid amplification tests for clinic-based testing.

Results Based on observed levels of clinic-based testing, our baseline model predicted an equilibrium HIV prevalence of 18.6%. If all men replaced clinic-based testing with home-use tests, prevalence increased to 27.5% if home-use testing did not impact testing frequency and to 22.4% if home-use testing increased testing frequency 3-fold. Regardless of how much home-use testing increased testing frequency, any replacement of clinic-based testing with home-use testing increased prevalence. These increases in HIV prevalence were mostly caused by the relatively long window period of the currently approved test. If the window period of a home-use test were 2 months instead of 3 months, prevalence would decrease if all MSM replaced clinic-based testing with home-use tests and tested more than 2.6 times more frequently.

Conclusions Our model suggests that if home-use HIV tests replace supplement clinic-based testing, HIV prevalence may increase among Seattle MSM, even if home-use tests result in increased testing.

A mathematical model found that replacing clinic-based HIV testing with home-use tests may increase HIV prevalence among men who have sex with men in Seattle, even if testing increases. Supplemental Digital Content is available in the article.

From the Departments of *Medicine, †Epidemiology, and ‡Global Health, University of Washington, Seattle, WA; and §HIV/STD Program, Public Health–Seattle & King County, Seattle, WA

Acknowledgments: The authors thank Drs Julia Dombrowski, Aditya Khanna, Mari Kitahata, Janine Maenza, and Matthew Golden of the University of Washington.

Conflicts of interest and source of funding: This work was supported by the National Institutes of Health Grant Nos. R01MH086360 and R00HD057533, as well as the University of Washington Center for AIDS Research, a National Institutes of Health–funded program (P30 AI027757). The authors have no conflicts of interest to declare.

Disclaimer: The content is solely the responsibility of the authors and does not necessarily represent the official views of the National Institutes of Health.

Correspondence: David A. Katz, PhD, MPH, University of Washington, 325 Ninth Ave, Box 359777, Seattle, WA 98104. E-mail:

Received for publication February 12, 2013, and accepted September 6, 2013.

Supplemental digital content is available for this article. Direct URL citations appear in the printed text, and links to the digital files are provided in the HTML text of this article on the journal’s Web site (

© Copyright 2014 American Sexually Transmitted Diseases Association