Transmitted Disease Testing Research Articles

Concurrent sex partners and risk for sexually transmitted diseases among adolescents.

A large percentage of sexually active adolescents have multiple sex partners and are at high risk of acquiring sexually transmitted diseases (STDs). Little is known about adolescents' patterns of sexual partnerships (e.g., concurrent versus serial) and how these patterns influence STD risk. To determine the frequency with which adolescents have concurrent partners during a main relationship and the association between having concurrent partners and STD risk. Adolescents seeking care at a public STD clinic were recruited from March, 1996, to May, 1998. Demographic and behavioral data were obtained during an interviewer-administered questionnaire. Sexually transmitted disease testing and physical exams were performed by clinicians. Of those adolescents who reported having at least one main partner during the previous 6 months (n = 245), 110 (44.9%) had multiple partners, and 76 (31%) had at least one concurrent partner during a main relationship. Greater number of concurrent partners was associated with STD diagnosis/exposure after controlling for number of sex partners (OR = 1.6; 95% CI, 1.1-2.4). A significant percentage of adolescents have concurrent partners during a main relationship, and having concurrent partners increases STD risk.

The vaginal introitus: A novel site for Chlamydia trachomatis testing in women

OBJECTIVE: We evaluated the vaginal introitus as a noninvasive sampling site for testing for Chlamydia trachomatis. STUDY DESIGN: Swabs from the vaginal introitus were obtained from 300 women attending a sexually transmitted diseases clinic and tested for the presence of Chlamydia trachomatis by polymerase chain reaction. Additionally, 200 of these women self-collected an additional introitus swab and submitted a urine sample for polymerase chain reaction testing. These samples were compared with polymerase chain reaction, culture, and enzyme immunoassay for Chlamydia trachomatis from endocervical samples and polymerase chain reaction and culture on urethral swabs. Patients were determined to be infected with Chlamydia trachomatis by a positive culture result from any site or a confirmed positive result by polymerase chain reaction with an alternate primer. RESULTS: The sensitivity of vaginal introitus swabs obtained by health care providers for the detection of urogenital Chlamydia trachomatis was 92% (95% confidence interval 83 to 100), greater than polymerase chain reaction, culture, or enzyme immunoassay of the cervix or urethra. The sensitivity by polymerase chain reaction of patient self-collected swabs was 81%. Sampling of the vaginal introitus, by both health care workers and the patient herself, performed as well as commonly used diagnostic tests that require vaginal speculum examination. The sensitivity of polymerase chain reaction testing of urine samples was 73%. CONCLUSION: The vaginal introitus represents a highly effective noninvasive specimen collection site for Chlamydia trachomatis testing by polymerase chain reaction. Self-collection of introitus specimens may revolutionize sexually transmitted disease testing by eliminating the need for a speculum examination by skilled health care personnel. (AM J OBSTET GYNECOL 1996;174:1542-6.)

Confirmatory assay increases specificity of the chlamydiazyme test for Chlamydia trachomatis infection of the cervix

Enzyme immunoassays for the detection of chlamydial antigens are commonly used to diagnose Chlamydia trachomatis infection. As is true for all nonculture methods, the specificities of these tests are a concern. A confirmatory blocking assay (Abbott Laboratories, North Chicago, Ill.) was evaluated at four sexually transmitted disease test sites. This assay is designed to confirm true-positive Chlamydiazyme (CZ) specimens and to identify false-positive CZ reactions caused by cross-reacting bacteria. Cervical specimens were collected from 2,891 women. Chlamydia prevalence by tissue culture (TC) was 9.2% (266 of 2,891 specimens). Compared with TC, the sensitivity and specificity of CZ were 78.9% (210 of 266 specimens) and 98.2% (2,577 of 2,625 specimens), respectively. There were 48 CZ false-positive reactions. The direct fluorescent-antibody test (DFA) was positive for 31 of 48 false-positive reactions, indicating culture misses. Thus, when the standard was both TC and DFA, CZ sensitivity was 81.1% and CZ specificity was 99.3%. Of the 17 CZ-positive patients who were negative by both TC and DFA, 3 were negative on repeat CZ and 11 of 14 were identified as false positive by the confirmatory assay. The confirmatory test was positive for CZ-positive women who were positive by TC or DFA. Use of the confirmatory test, which increased the specificity to 99.9%, would increase confidence in positive CZ results and make the test more useful for screening populations with a low prevalence of C. trachomatis infection.