Evaluation of self-taken samples for the presence of genital Chlamydia trachomatis infection in women using the ligase chain reaction assay

Detection of human papillomavirus DNA in urine. A review of the literature

The detection of human papillomavirus (HPV) DNA in urine, a specimen easily obtained by a non-invasive self-sampling method, has been the subject of a considerable number of studies. This review provides an overview of 41 published studies; assesses how different methods and settings may contribute to the sometimes contradictory outcomes; and discusses the potential relevance of using urine samples in vaccine trials, disease surveillance, epidemiological studies, and specific settings of cervical cancer screening. Urine sampling, storage conditions, sample preparation, DNA extraction, and DNA amplification may all have an important impact on HPV DNA detection and the form of viral DNA that is detected. Possible trends in HPV DNA prevalence in urine could be inferred from the presence of risk factors or the diagnosis of cervical lesions. HPV DNA detection in urine is feasible and may become a useful tool but necessitates further improvement and standardization.

Acceptability of chlamydia screening using self-taken vaginal swabs

In the first phase of the National Chlamydia Screening Programme (NCSP), the majority of sites involved offered testing with urine sample. Camden & Islington (C&l) were the first site to offer testing with self-taken vaginal swabs (SVS). SVS are appropriate specimens for diagnosing chlamydia by nucleic acid amplification tests. This study aimed to assess the uptake and acceptability of chlamydia screening using SVS within C&l contraceptive clinics. Data collected from women participating in the NCSP between June 2003 and April 2004 were analysed. Of the 3936 women who accepted screening, 90.4% provided a SVS and only 5.8% accepted the offer of providing a urine sample as an alternative to SVS. Women over 19 years and women from Asian ethnic groups were most likely to decline any screening. No woman stated a reluctance to provide a SVS as a reason for declining screening, confirming the acceptability of SVS for chlamydia screening.

Vulvovaginal-swab or first-catch urine specimen to detect Chlamydia trachomatis in women in a community setting?

Screening for chlamydia in women is widely recommended. We evaluated the performance of two nucleic acid amplification tests for detecting Chlamydia trachomatis in self-collected vulvovaginal-swab and first-catch urine specimens from women in a community setting and a strategy for optimizing the sensitivity of an amplified enzyme immunoassay on vulvovaginal-swab specimens. We tested 2,745 paired vulvovaginal-swab and urine specimens by PCR (Roche Cobas) or strand displacement amplification (SDA; Becton Dickinson). There were 146 women infected with chlamydia. The assays detected 97.3% (95% confidence interval [CI], 93.1 to 99.2%) of infected patients with vulvovaginal-swab specimens and 91.8% (86.1 to 95.7%) with urine specimens. We tested 2,749 vulvovaginal-swab specimens with both a nucleic acid amplification test and a polymer conjugate-enhanced enzyme immunoassay with negative-gray-zone testing. The relative sensitivities obtained after retesting specimens in the negative gray zone were 74.3% (95% CI, 62.8 to 83.8%) with PCR and 58.3% (95% CI, 46.1 to 69.8%) with SDA. In community settings, both vulvovaginal-swab and first-catch urine specimens from women are suitable substrates for nucleic acid amplification tests, but enzyme immunoassays, even after negative-gray-zone testing, should not be used in screening programs.

High analytical sensitivity and low rates of inhibition may contribute to detection of Chlamydia trachomatis in significantly more women by the APTIMA Combo 2 assay

The clinical sensitivity of nucleic acid amplification tests may be determined by analytical sensitivity and inhibitors in patient samples. We established endpoints for detection of propagated Chlamydia trachomatis L2 434, diluted according to swab and urine protocols for APTIMA Combo 2 (AC2), ProbeTec ET (PT), and Amplicor (AMP) assays. AC2 was 1,000-fold more sensitive than PT and 10-fold more sensitive than AMP on mock swab specimens. For urine, AC2 analytical sensitivity was 100-fold greater than those of the other assays. Spiking an aliquot of each clinical-trial sample from 298 women demonstrated inhibition rates in first-void urine (FVU), cervical swabs (CS), and vaginal swabs (VS) of 12.1%, 12.8%, and 10.4% for AMP; 27.2%, 2%, and 2%, for PT; and 0.3%, 1.7%, and 1.3% for AC2. Inhibition of our C. trachomatis spike and the PT or AMP amplification controls from the manufacturers showed less than 50% correlation. Using an infected-patient reference standard (a specimen positive in at least two tests or a single test positive in two of three samples) in AC2, the VS identified 68/69 (98.6%) infected women compared to CS (89.9%) or FVU (81.2%). Significantly fewer women were identified by PT (65.2%, 63.8%, and 66.7%) or AMP (65.2%, 59.4%, and 56.5%) with the three specimens. By individual specimen type, AC2 confirmed virtually all PT- and AMP-positive specimens, but rates of AC2 confirmation by AMP or PT ranged from 62.9 to 80.3%. The AC2 test identified significantly more women infected with C. trachomatis (P = 0.001). Vaginal swabs appear to be the specimen of choice for screening.

Prevalence of Mycoplasma genitalium in early pregnancy and relationship between its presence and pregnancy outcome

Mycoplasma genitalium is associated with cervicitis and pelvic inflammatory disease but little is known about its role in pregnancy. We investigated the prevalence of M. genitalium by polymerase chain reaction assay on urine specimens from 1216 pregnant women (mean age 31years) presenting before 10 weeks of gestation in 32 general practices. The prevalence of M. genitalium was 0.7% (6/915, 95% CI 0.1-1.2). It was more common in women aged < 20 years, women of Afro-Caribbean or black African ethnic origin, women in social classes 3-5 and single women. Only one woman with M. genitalium infection miscarried, and none of those followed up to term had a preterm birth, although the numbers were small. The low prevalence of M. genitalium infection suggests it is unlikely to be an important risk factor in adverse pregnancy outcome in healthy women in the community.

Testing for Chlamydial and Gonorrheal Infections Outside of Clinic Settings

BACKGROUND

Nucleic acid amplification tests (NAATs) provide new technology that makes it feasible to initiate testing for Chlamydia trachomatis (CT) and Neisseria gonorrhoeae (GC) infection outside of clinic settings.

METHODS

We summarized the English-language literature describing chlamydial or gonorrheal testing with self-collection of urine or vaginal specimens outside of clinic settings in developed countries published between January 1995 and August 2002.

RESULTS

Testing for CT or GC infection has been initiated in school, community, and home settings. Purposes include screening of asymptomatic populations, improving quality of clinic-based health care, and research. Challenges include defining and reaching target populations, overcoming logistic issues, developing communication and counseling strategies, and determining whether alternative testing strategies are effectively reducing infection rates.

CONCLUSIONS

The use of NAATs to detect CT and GC infection outside of clinic settings will undoubtedly continue. Future research should focus on how to best use this technology to reduce rates of infection.

Preference among female Army recruits for use of self-administrated vaginal swabs or urine to screen for Chlamydia trachomatis genital infections

BACKGROUND

Use of self-administered vaginal swabs (SAS) for the detection of Chlamydia trachomatis by nucleic acid amplification tests simplifies specimen collection and transport, especially for women in nonclinical settings.

GOAL

We investigated the preference and comfort level of military women for the collection of SAS, compared with urine, for the diagnosis of genital chlamydial infections.

STUDY DESIGN

During March through August 1999, female Army recruits in basic training at Fort Jackson, South Carolina, were invited to participate in the study. Participants were requested to complete a questionnaire after providing both first-void urine (FVU) and SAS specimens. Participant characteristics, preferences, and comfort levels were assessed using multivariate logistic regression.

RESULTS

From 4496 eligible female recruits, 1403 (31%) completed questionnaires and 1382 provided both specimens; 11.8% (166 of 1403) of participants were infected with chlamydia. The relative sensitivity and specificity of the C. trachomatis Ligase Chain Reaction test on SAS in 1382 matched pairs was 81.1% and 98.6%, respectively, using the test result on urine specimens as the comparison standard. Most of the participants (90.8%) reported that they felt comfortable collecting the FVU specimen, and 69.6% indicated that they felt comfortable collecting SAS. Either specimen collection type received high acceptability at home and in the field, and more women reported that they would collect FVU than reported they would collect SAS in the future (in the field: FVU: 79.4%, SAS: 68.8%, P <0.001); at home: FVU: 90.9%, SAS: 82.9%, P <0.001). When questioned about ease of use, 60.4% of women reported that urine was the easier method. Preferences for SAS were associated with being white and having had sexual risk behaviors in the past 3 months.

CONCLUSION

A study of preferences for urine versus self-administered vaginal swabs for the detection of C. trachomatis in military women showed that women generally found SAS acceptable. SAS should be a feasible alternative to urine collection in situations in which specimen storage or transport is an issue.

Comparing first-void urine specimens, self-collected vaginal swabs, and endocervical specimens to detect Chlamydia trachomatis and Neisseria gonorrhoeae by a nucleic acid amplification test

We set out to determine the prevalences of Chlamydia trachomatis and Neisseria gonorrhoeae by ligase chain reaction as well as to determine the prevalence of Trichomonas vaginalis by culture in a large and diverse national sample of non-health-care-seeking young women entering the military; we also sought to compare the abilities of three different techniques of collecting specimens (first-void urine, self-collected vaginal swab, and clinician-collected endocervical swab) to identify a positive specimen. A cross-sectional sample of young women was voluntarily recruited; as a part of their routine entry pelvic examination visit, they completed a self-administered reproductive health questionnaire and provided first-void urine (used to detect C. trachomatis and N. gonorrhoeae) and self-collected vaginal swabs (used to detect C. trachomatis, N. gonorrhoeae, and T. vaginalis). The number of positive tests divided by the number of sexually active women screened by each sampling method determined the rates of prevalence. The rate of infection with any of the three sexually transmitted diseases (STDs) tested was 14.1%. The total positive rates for each STD (identified by >/=1 specimen) were the following: for C. trachomatis, 11.6%; N. gonorrhoeae, 2.4%; and T. vaginalis, 1.7%. The proportions of positives identified by specimen type were, for C. trachomatis and N. gonorrhoeae, respectively, endocervix, 65 and 40%; urine, 72 and 24%; and vagina, 81 and 72%. The proportions of positives when specimen results were combined were, for C. trachomatis and N. gonorrhoeae, respectively, cervix plus urine, 86 and 49%; cervix plus vagina, 91 and 93%; and vagina plus urine, 94 and 79%. We concluded that STDs were epidemic in this population. Self-collected vaginal swabs identified the highest number of positive test results among single specimens, with the combined cervix-vagina results identifying the highest number of positive results. Self-collected vaginal swab collections are a feasible alternative to cervical specimen collections in this population, and the use of multiple types of specimens increases the positive yield markedly.

Chlamydial infection: an accurate model for opportunistic screening in general practice

OBJECTIVES

To estimate the prevalence of Chlamydia trachomatis in women in general practice and to assess risk factors associated with infection.

METHODS

The study was carried out in 2001-2 in different general practices in Antwerp, Belgium. Sexually active women, visiting their general practitioner for routine gynaecological care (mostly pill prescription or PAP smear), were offered opportunistic screening for chlamydia. 787 participants aged 15-40 delivered a self taken vaginal sample and filled in a questionnaire which included questions on demographic variables, urogenital symptoms, sexual history, and sexual behaviour. Samples were tested for presence of chlamydial DNA by means of a ligase chain reaction (LCR) assay, and positives were confirmed by two other amplification assays (PCR and SDA).

RESULTS

Overall prevalence was 5.0% (95% CI: 3.5 to 6.5). Determinants of infection in logistic regression analysis were age 18-27 years, >1 partner in the past year, no use of contraceptives, frequent postcoital bleeding, having a symptomatic partner, painful micturition, and living in the inner city. The area under the ROC curve in the full model was 0.88. Selective screening based on a combination of the five first determinants detects 92.3% of infections in this sample; 37.5% of the population would need to be screened.

CONCLUSION

Targeted screening for chlamydial infection is possible, even in a heterogeneous group of general practice attendants. Implementing this model would require considerable communication skills from healthcare providers.

Female prisoners' preferences of collection methods for testing for Chlamydia trachomatis and Neisseria gonorrhoeae infection

BACKGROUND

There is an increasing reliance on noninvasive techniques to collect specimens for the detection of sexually transmitted infections. The acceptability of these methods among the general population has been explored, but little is known about their acceptability among women confined in prison.

GOAL

The goal was to compare female prisoners' preferences for collection of specimens (self-collected vaginal swab specimens, urine collection, or pelvic examination) for detection of Chlamydia trachomatis and Neisseria gonorrhoeae.

STUDY DESIGN

A cross-section of inmates in a large federal prison provided urine samples and self-collected vaginal swab specimens. Women then completed a questionnaire regarding the ease of each method and their preferences for future specimen collection.

RESULTS

A total of 535 women between the ages of 18 and 52 years (median = 33) participated in the study. More than half of the participants (57%) reported no difference between urine and swab in terms of ease of collection. Approximately 30% of participants said they would prefer to give a swab specimen in the future rather than collect urine (21%), but nearly half of the women expressed no preference for one method over the other. Most participants (60%) expressed a preference for providing a self-collected swab specimen rather than having a pelvic examination (23%), but nearly 17% expressed a preference for one over the other.

CONCLUSION

The study population of female federal prisoners expressed no aversion to the self-collection of either vaginal swab or urine specimens for STD testing. A majority of participants expressed a preference for noninvasive techniques rather than a pelvic examination.

Parallel observation of four methods for screening women under 25 years of age for genital infection with Chlamydia trachomatis

OBJECTIVES

To compare four methods of screening women for Chlamydia trachomatis in an obstetrics and gynaecology department.

STUDY DESIGN

A total of 303 healthy women under 25 years were recruited from antenatal, induced abortion, and family planning clinics. Each underwent parallel testing of endocervical specimens by enzyme immunoassay (EIA) and ligase chain reaction (LCR), vulval swabs by LCR, and urine by LCR. Outcome measures included sensitivity, specificity, acceptability of each method, and the influence of pregnancy.

RESULTS

Overall prevalence (95% CI) was 9.9% (6.8-14%). All methods had a high rate of detection (75-100%), not affected by pregnancy. Urine was most acceptable, followed by vulval swabbing.

CONCLUSIONS

Opportunistic screening of women under 25 years attending obstetric and gynaecology affiliated clinics found high rates of C. trachomatis infection. Both urine and vulval swab methods were highly sensitive, acceptable, and not affected by pregnancy status. Due to pragmatic issues surrounding the urine method, screening by vulval swabs deserves wider recognition.

Opportunistic screening for genital chlamydial infection. I: acceptability of urine testing in primary and secondary healthcare settings

OBJECTIVES

To determine the acceptability of opportunistic screening for Chlamydia trachomatis in young people in a range of healthcare settings.

DESIGN

An opportunistic screening programme (1 September 1999 to 31 August 2000) using urine samples tested by ligase chain reaction (LCR). Data on uptake and testing were collected and in-depth interviews were used for programme evaluation.

SETTING

General practice, family planning, genitourinary medicine clinics, adolescent sexual health clinics, termination of pregnancy clinics, and women's services in hospitals (antenatal, colposcopy, gynaecology and infertility clinics) in two health authorities (Wirral and Portsmouth and South East Hampshire). Main participants: Sexually active women aged between 16 and 24 years attending healthcare settings for any reason.

MAIN OUTCOME MEASURES

Uptake data: proportion of women accepting a test by area, healthcare setting, and age; overall population coverage achieved in 1 year. Evaluation data: participants' attitudes and views towards opportunistic screening and urine testing.

RESULTS

Acceptance of testing by women (16-24 years) was 76% in Portsmouth and 84% in Wirral. Acceptance was lower in younger women (Portsmouth only) and varied by healthcare setting within each site. 50% of the target female population were screened in Portsmouth and 39% in Wirral. Both the opportunistic offer of screening and the method of screening were universally acceptable. Major factors influencing a decision to accept screening were the non-invasive nature of testing and treatment, desire to protect future fertility, and the experimental nature of the screening programme.

CONCLUSIONS

An opportunistic model of urine screening for chlamydial infection is a practical, universally acceptable method of screening.

Head-to-head multicenter comparison of DNA probe and nucleic acid amplification tests for Chlamydia trachomatis infection in women performed with an improved reference standard

Few evaluations of tests for Chlamydia trachomatis have compared nucleic acid amplification tests (NAATs) with diagnostic tests other than those by culture. In a five-city study of 3,551 women, we compared the results of commercial ligase chain reaction (LCR) and PCR tests performed on cervical swabs and urine with the results of PACE 2 tests performed on cervical swabs, using independent reference standards that included both cervical swabs and urethral swab-urine specimens. Using cervical culture as a standard, the sensitivities of PACE 2, LCR, and PCR tests with cervical specimens were 78.1, 96.9, and 89.9%, respectively, and the specificities were 99.3, 97.5, and 98.2%, respectively. Using either cervical swab or urine LCR-positive tests as the standard decreased sensitivities to 60.8% for PACE 2 and to 75.8 and 74.9% for PCR with cervical swabs and urine, respectively. Specificities increased to 99.7% for PACE 2 and to 99.7 and 99.4% for PCR with cervical swabs and urine, respectively. Sensitivities with a cervical swab-urine PCR standard were 61.9% for PACE 2 and 85.5 and 80.8% for LCR with cervical swabs and urine, respectively. Specificities were 99.6% for PACE 2 and 99.0 and 98.9% for LCR with cervical swabs and urine, respectively. Cervical swab versus urine differences were significant only for PCR specificities (P = 0.034). Overall, LCR sensitivity exceeded that of PCR, and sensitivities obtained with cervical swabs exceeded those obtained with urine specimens by small amounts. These data have substantiated, using a large multicenter sample and a patient standard, that LCR and PCR tests performed on endocervical swabs and urine are superior to PACE 2 tests for screening C. trachomatis infections in women. In our study, NAATs improved the detection of infected women by 17 to 38% compared to PACE 2.

Sexual behaviour in Britain: reported sexually transmitted infections and prevalent genital Chlamydia trachomatis infection

BACKGROUND

Studies of the epidemiology of sexually transmitted infections (STI) are largely based on surveillance data. As part of a national survey of sexual attitudes and lifestyles (Natsal 2000) in Britain, we estimated the frequency of self-reported STIs, and the prevalence of urinary Chlamydia trachomatis infection.

METHODS

We did a stratified probability sample survey of 11161 men and women aged 16-44 years in Britain. Computer assisted self-interviews contained items on the nature and timing of previously diagnosed STIs. Half of all sexually experienced respondents aged 18-44 years were invited to provide a urine sample for ligase chain reaction testing for C trachomatis infection.

FINDINGS

10.8% of men and 12.6% of women reported ever having an STI, 3.6% of men and 4.1% of women reported ever being diagnosed with genital warts, and 1.4% of men and 3.1% of women reported previous infection with C trachomatis. 76% of men and 57% of women ever diagnosed with an STI had been to a GUM clinic. C trachomatis was found in 2.2% (95% CI 1.5-3.2) of men and 1.5% (95% CI 1.11-2.14) of women with age-specific prevalence being highest among men aged 25-34 (3.1%) and women aged 16-24 years (3.0%). Non-married status, age, and reporting partner concurrency or two or more sexual partners in the past year were independently associated with infection with C trachomatis.

INTERPRETATION

We show substantial heterogeneity in distribution of reported STIs, and the demographic and behavioural determinants of prevalent genital chlamydial infection. The results have potentially wide application for proposed chlamydia screening programmes which, given the demonstrated prevalence, must now proactively seek to involve men.

Evaluation of a modified sanitary napkin as a sample self-collection device for the detection of genital chlamydial infection in women

A modified sanitary napkin was compared with endocervical swab and urine specimens for the detection of urogenital Chlamydia trachomatis infection. Endocervical swabs and/or first-catch urine were collected from 510 women at medical or community settings in Quebec City. Participants were also asked to wear a modified sanitary napkin (Ezy-Detek) during 4 consecutive hours and to bring it back to the clinic or mail it to the laboratory. Endocervical and urine specimens were tested using the Cobas Amplicor CT/NG assay (Roche Diagnostic Systems) according to the manufacturer's instructions, as were specimens collected with the napkin after adequate preparation. If the PCR test result was positive on the endocervical sample or on any two samples, a woman was considered to be infected. PCR testing results on paired samples were identical for 493 (96.6%) of 510 women. According to the definition given above, 58 (11.3%; 95% confidence interval [CI], 8.7 to 14.5%) women were infected with C. trachomatis. The sensitivity and specificity of PCR testing on modified sanitary napkin specimens were, respectively, 93.1% (54 of 58; 95% CI, 83.3 to 98.1%) and 98.9% (447 of 452; 95% CI, 97.4 to 99.6%) compared to 81.0% (47 of 58; 95% CI, 68.6 to 90.1%) and 100% (451 of 451; 95% CI, 99.2 to 100%) for urine specimens. The positive and negative predictive values were, respectively, 91.5% (54 of 59) and 99.1% (447 of 451) for the sanitary napkin specimens compared to 100% (47 of 47) and 97.6% (451 of 462) for urine samples. These results suggest that a modified sanitary napkin represents an effective noninvasive device for self-collection of specimens to detect urogenital C. trachomatis infection.

New tests for bacterial sexually transmitted diseases

Recent advances in diagnostic tests for sexually transmitted diseases include the development of a synthetic Venereal Disease Research Laboratory reagent that will improve the sensitivity and stability of nontreponemal serologic tests for syphilis. A second generation user friendly and high throughput nucleic acid amplification test for Chlamydia trachomatis and Neisseria gonorrhoeae has also been developed.