LOS ANGELES — Free home swab test kits requested via the Internet have detected hundreds of cases of chlamydia, gonorrhea, and Trichomonas using a simple online recruitment strategy that was so effective it is now being extended to several states.

The novel “I Want the Kit” program was devised by Johns Hopkins University researchers in 2004, alerting young women to facts about chlamydia and other sexually transmitted diseases, and offering kits with prepaid postage to allow for confidential testing.

Word went out via radio, magazine, and newspaper advertisements in Baltimore initially, but soon Internet traffic began to dominate responses.

“Our original objective was to reach out to teens who might have issues with fear and privacy going to a clinic,” Dr. Charlotte A. Gaydos said at the annual meeting of the Society for Adolescent Medicine, where she presented interim study results.

Nearly 5,000 kits have been requested to date, 97% through the study's site www.iwantthekit.org

About one-third of the kits were returned with vaginal swab samples collected at home, with positive chlamydia results in 10% and positive gonorrhea tests in 1%, Dr. Gaydos, professor of infectious diseases at the university, said in an interview.

Trichomonas testing was added in 2006 and has resulted in a detection rate of 12% in 1,032 returned samples.

Dr. Gaydos reported that more than 98% of women said the instructions for collection were easy, 97% said the collection itself was easy, and 92% said they would use an Internet-based program again for STD testing.

Once someone requests a kit, it arrives at her home in a plain envelope, listing as the return address only the street address of the project in Baltimore. The packet contains detailed instructions, the test swab, and return packaging—including postage.

“I'm reaching out to the 14-year-old who has no money for postage and is not going to tell her mother she's sexually active,” said Dr. Gaydos.

Completed samples can be dropped off in any mailbox and are tested by nucleic acid amplification tests for all three STDs. The test method has been found in previous research to be highly accurate—and even more so with self-collected vaginal swabs than with urine specimens.

Positive test results are followed up by referrals to free treatment clinics close to the adolescents' or women's homes.

Beyond identifying cases of sexually transmitted infections that might not otherwise have been detected, the researchers were able to obtain demographic and sexual information from women who responded.

A few 14-year-olds participated but none were positive for chlamydia.

On the other hand, more than one-quarter of all respondents were aged 15–19 years, and they had the highest prevalence for chlamydia of any age group, at 15%.

About one-third of the respondents were aged 20–24 years. In this group, the prevalence rate was 11%.

Somewhat surprising to researchers was the high rate of participation among women 25–29 years (18% of respondents, with a prevalence rate of 7%) and those over 30 years (22% of the respondents, with a prevalence rate of 1%).

Researchers found a high rate of sexual risk among women participating in the study, with 55% reporting a history of an STD, 59% reporting more than one sex partner in the previous 90 days, 39% reporting a new partner in the previous 90 days, more than half reporting drinking before sex, 31% reporting anal sex, and 23% reporting a history of forced sex.

In a multivariate logistic regression analysis, only three factors were independently associated with a positive chlamydia test: black race vs. white (odds ratio, 3.4); age less than 25 years (OR, 3.4); and having a new partner during the past 90 days (OR, 1.7).

Among all respondents (most of whom did not test positive for an STD), 62% reported at least one symptom, including vaginal discharge (48%), lower abdominal pain (17%), pain during intercourse (15%), abnormal vaginal bleeding (7%), and/or pain during urination (6%).

Several audience members expressed concern about undiagnosed conditions in the population, but Dr. Gaydos assured them that the Web site makes it clear that respondents should seek medical attention in the face of symptoms and have a regular care provider.

A parallel study is ongoing for males, she said. The “I Want the Kit” testing is currently available via the Internet to girls and young women in Maryland; West Virginia; Washington, D.C.; Denver; and some counties in Illinois.

“Theoretically, this program could go anywhere in the U.S.,” she said.

Every state receives Centers for Disease Control and Prevention funding for free STD testing through the CDC Infertility Prevention Program, and this strategy may reach a very high-risk group with intensive education and a means of confidentially, conveniently accessing a reliable test. Involving public health systems is critical, said Dr. Gaydos, because many commercial Internet sites offering STD tests use unreliable testing protocols. In fact, some are completely fraudulent, she said.

Dr. Gaydos disclosed that Gen-Probe, Inc. of San Diego provided free diagnostic kits for the study.

Free Home Chlamydia Tests Net High Return