Background: Applicator dye staining and ultraviolet (UV) light have been used in trials to measure adherence, but not in the setting of before and after sex gel dosing (BAT-24). This study was designed to determine if semen or presex gel dosing impacts the sensitivity and specificity of a dye stain assay (DSA) for measuring vaginal insertion of placebo-filled applicators with BAT-24 dosing.
Methods: Healthy monogamous couples received Microlax-type applicators (Tectubes, Åstorp, Sweden) filled with hydroxyethylcelluose placebo gel. Women were instructed to vaginally insert 1 dose of gel before and a second dose after sex and to return applicators within 48 hours after sex. Applicators were stained to detect semen, followed by UV then DSA, and scored by 2 readers. Positive and negative controls were randomly included in applicator batches.
Results: Fifteen couples completed the study. Each woman returned at least 6 applicators over a 30-day period. The sensitivity for insertion of postsex applicators was higher for UV (97%) compared with DSA (90%), and the specificity was similar (≥96%). For presex applicators, the sensitivity and specificity were higher for DSA (100%) compared with UV testing (87% sensitivity, 96% specificity). Among returned postsex applicators, 95% tested positive by UV compared with 87% by DSA. Agreement between readers was significantly better on the presex applicators for DSA than for UV, and for postsex readings, agreement was less than half that for UV, although the results were not statistically significant.
Conclusions: Applicator tests are feasible for measuring adherence in trials with gel dosing before and after sex.
A study of healthy, monogamous couples in Bronx, New York, found that a dye stain assay and ultraviolet light test performed on applicators used after sex accurately detected vaginal insertion.
From the *Albert Einstein College of Medicine and Montefiore Medical Center, Bronx, NY; †The Population Council, New York, NY; ‡Albert Einstein Cancer Center, Bronx, NY; and §National Cancer Institute, National Institutes of Health, Bethesda, MD
Acknowledgments: Than authors thank the couples who participated in this study for their time and effort. The contributions of Lilia Espinoza, Nicole Marshall, Lisa Felder, Randall Teeter, Ashley Huber, and Letisha Vaughn from Einstein and Montefiore and Jose Fernández-Romero, Deb Tolenaar, and Thomas Zydowsky from Population Council are acknowledged as critical in the development and implementation of this study. The manuscripts’ contents are solely the responsibility of the authors and do not necessarily represent the official views of Einstein, Montefiore, Population Council, or of the National Institutes of Health (NIH).
Conflicts of interest and source of funding: This study was supported in part by the Population Council through grants from the United States Agency for International Development and Swedish Ministry of Finance and funds from the NIH including R01 CA-148966, Harold and Muriel Block Institute for Clinical and Translational Research at Einstein and Montefiore (NCATS UL1 TR001073), and Einstein-Montefiore Center for AIDS Research (NIH AI-051519). None of the authors declare any conflicts of interest.
Correspondence: Marla J. Keller, MD, Albert Einstein College of Medicine, 1300 Morris Park Ave, Harold and Muriel Block Bldg, Room 512, Bronx, NY 10461. E-mail: firstname.lastname@example.org.
Received for publication July 1, 2013, and accepted August 28, 2013.