Limitations of screening tests for the detection of Chlamydia trachomatis in asymptomatic adolescent and young adult women

Screening for Chlamydia and Gonorrhea: US Preventive Services Task Force Recommendation Statement

IMPORTANCE

Chlamydia and gonorrhea are among the most common sexually transmitted infections in the US. Infection rates are highest among adolescents and young adults of both sexes. Chlamydial and gonococcal infections in women are usually asymptomatic and may lead to pelvic inflammatory disease and its associated complications. Newborns of pregnant persons with untreated infection may develop neonatal chlamydial pneumonia or gonococcal or chlamydial ophthalmia. Infection in men may lead to urethritis and epididymitis. Both types of infection can increase risk of acquiring or transmitting HIV.

OBJECTIVE

To update its 2014 recommendation, the US Preventive Services Task Force (USPSTF) commissioned a systematic review to evaluate the benefits and harms of screening for chlamydia and gonorrhea in sexually active adolescents and adults, including pregnant persons.

POPULATION

Asymptomatic, sexually active adolescents and adults, including pregnant persons.

EVIDENCE ASSESSMENT

The USPSTF concludes with moderate certainty that screening for chlamydia in all sexually active women 24 years or younger and in women 25 years or older who are at increased risk for infection has moderate net benefit. The USPSTF concludes with moderate certainty that screening for gonorrhea in all sexually active women 24 years or younger and in women 25 years or older who are at increased risk for infection has moderate net benefit. The USPSTF concludes that the current evidence is insufficient to assess the balance of benefits and harms of screening for chlamydia and gonorrhea in men.

RECOMMENDATION

The USPSTF recommends screening for chlamydia in all sexually active women 24 years or younger and in women 25 years or older who are at increased risk for infection. (B recommendation) The USPSTF recommends screening for gonorrhea in all sexually active women 24 years or younger and in women 25 years or older who are at increased risk for infection. (B recommendation) The USPSTF concludes that the current evidence is insufficient to assess the balance of benefits and harms of screening for chlamydia and gonorrhea in men. (I statement).

Screening for Chlamydial and Gonococcal Infections: Updated Evidence Report and Systematic Review for the US Preventive Services Task Force

IMPORTANCE

The 2014 US Preventive Services Task Force (USPSTF) recommendation statement supported the effectiveness of screening for chlamydia and gonorrhea in asymptomatic, sexually active women 24 years or younger and in older women at increased risk for infection, although evidence for screening in men was insufficient.

OBJECTIVE

To update the 2014 USPSTF review on screening for chlamydial and gonococcal infection in adults and adolescents, including those who are pregnant.

DATA SOURCES

Cochrane Central Register of Controlled Trials, Cochrane Database of Systematic Reviews, and Ovid MEDLINE (January 1, 2014, through May 28, 2020) with surveillance through May 21, 2021.

STUDY SELECTION

Randomized clinical trials and observational studies of screening effectiveness, accuracy of risk stratification and alternative screening methods, accuracy of tests, and screening harms.

DATA EXTRACTION AND SYNTHESIS

One investigator abstracted data; a second checked accuracy. Two investigators independently assessed study quality.

MAIN OUTCOMES AND MEASURES

Complications of infection; infection transmission or acquisition; diagnostic accuracy of anatomical site-specific testing and collection methods; screening harms.

RESULTS

Twenty-seven studies were included (N = 179 515). Chlamydia screening compared with no screening was significantly associated with reduced risk of pelvic inflammatory disease (PID) in 2 of 4 trials and with reduced hospital-diagnosed PID (0.24% vs 0.38%); relative risk, 0.6 [95% CI, 0.4-1.0]), but not clinic-diagnosed PID or epididymitis, in the largest trial. In studies of risk prediction instruments in asymptomatic women, age younger than 22 years demonstrated comparable accuracy to extensive criteria. Sensitivity of chlamydial testing was similar at endocervical (89%-100%) and self- and clinician-collected vaginal (90%-100%) sites for women and at meatal (100%), urethral (99%), and rectal (92%) sites for men but lower at pharyngeal sites (69.2%) for men who have sex with men. Sensitivity of gonococcal testing was 89% or greater for all anatomical samples. False-positive and false-negative testing rates were low across anatomical sites and collection methods.

CONCLUSIONS AND RELEVANCE

Screening for chlamydial infection was significantly associated with a lower risk of PID in young women. Risk prediction criteria demonstrated limited accuracy beyond age. Testing for asymptomatic chlamydial and gonococcal infections was highly accurate at most anatomical sites, including urine and self-collected specimens. Effectiveness of screening in men and during pregnancy, optimal screening intervals, and adverse effects of screening require further evaluation.

Understanding Negative Predictive Value of Diagnostic Tests Used in Clinical Practice

Nurses review, evaluate, and use diagnostic test results on a routine basis. However, the skills necessary to evaluate a particular test using statistical outcome measures is often lacking. The purpose of this article is to examine and interpret the underlying principles for use of the statistical outcomes of diagnostic screening tests (sensitivity, specificity, and positive (PPV) and negative (NPV) predictive values, with a discussion about use of SpPIn [Specificity, Positive test = rule in], and SnNOut [Sensitivity, Negative test = rule out]) in advanced nursing clinical practice. The authors focus on NPVs because test results with high NPV are useful to practitioners when considering unnecessary, costly, and possibly risky treatments, whether using clinical assessment tool, test, or procedure or using polymerase chain reaction analysis of DNA test results. In this article, the authors emphasize the use of NPV in treatment decisions by providing examples from critical care, neonatal, and advanced forensic nursing, which become a framework for assessing decisions in the clinical arena. This commentary stresses the importance of the NPV of tests in preventing, detecting, and ruling out disease, where PPV may not be relevant for that purpose. Negative predictive value percentages inform treatment decisions when the provider understands the biology, chemistry, and foundation for testing methods used in clinical practices. The art of diagnosis, confirmed in a test's high NPV (meaning the patient probably does not have the disease when the test is negative), reassures provider treatment stewardship to do no harm.

Antenatal lower genital tract infection screening and treatment programs for preventing preterm delivery

BACKGROUND

Genital tract infection is associated with preterm birth (before 37 weeks' gestation). Screening for infections during pregnancy may therefore reduce the numbers of babies being born prematurely. However, screening for infections may have some adverse effects, such as increased antibiotic drug resistance and increased cost of treatment.

OBJECTIVES

To assess the effectiveness of antenatal lower genital tract infection screening and treatment programs for reducing preterm birth and subsequent morbidity.

SEARCH METHODS

We searched the Cochrane Pregnancy and Childbirth Group's Trials Register (30 November 2014), the Cochrane Central Register of Controlled Trials (The Cochrane Library 2014, Issue 7) and reference lists of retrieved reports.

SELECTION CRITERIA

We included all published and unpublished randomised controlled trials in any language that evaluated any described methods of antenatal lower genital tract infection screening compared with no screening.

DATA COLLECTION AND ANALYSIS

Two review authors independently assessed trials for inclusion and risk of bias, extracted data and checked for accuracy.

MAIN RESULTS

One study (4155 women at less than 20 weeks' gestation) met the inclusion criteria. The intervention group (2058 women) received infection screening and treatment for bacterial vaginosis, trichomonas vaginalis and candidiasis; the control group (2097 women) also received screening, but the results of the screening program were not revealed and women received routine antenatal care. The rate of preterm birth before 37 weeks' gestation was significantly lower in the intervention group (3% versus 5% in the control group) with a risk ratio (RR) of 0.55 (95% confidence interval (CI) 0.41 to 0.75; the evidence for this outcome was graded as of moderate quality). The incidence of preterm birth for infants with a weight equal to or below 2500 g (low birthweight) and infants with a weight equal to or below 1500 g (very low birthweight) were significantly lower in the intervention group than in the control group (RR 0.48, 95% CI 0.34 to 0.66 and RR 0.34; 95% CI 0.15 to 0.75, respectively; both graded as moderate quality evidence). Based on a subset of costs for preterm births of < 1900 g, the authors reported that for each of those preterm births averted, EUR 60,262 would be saved.

AUTHORS' CONCLUSIONS

There is evidence from one trial that infection screening and treatment programs for pregnant women before 20 weeks' gestation reduce preterm birth and preterm low birthweight. Infection screening and treatment programs are associated with cost savings when used for the prevention of preterm birth. Future trials should evaluate the effects of different types of infection screening programs.

Antenatal lower genital tract infection screening and treatment programs for preventing preterm delivery

BACKGROUND

Preterm birth is birth before 37 weeks' gestation. Genital tract infection is one of the causes of preterm birth. Infection screening during pregnancy has been used to reduce preterm birth. However, infection screening may have some adverse effects, e.g. increased antibiotic drug resistance, increased costs of treatment.

OBJECTIVES

To assess the effectiveness and complications of antenatal lower genital tract infection screening and treatment programs in reducing preterm birth and subsequent morbidity.

SEARCH STRATEGY

We searched the Cochrane Pregnancy and Childbirth Group's Trials Register (January 2008) and the Cochrane Central Register of Controlled Trials (The Cochrane Library 2007, Issue 2).

SELECTION CRITERIA

We included all published and unpublished randomised controlled trials in any language that evaluated any described methods of antenatal lower genital tract infection screening compared with no screening. Preterm births have been reported as an outcome.

DATA COLLECTION AND ANALYSIS

Two review authors independently assessed eligibility, trial quality and extracted data.

MAIN RESULTS

One study (4155 women) met the inclusion criteria. This trial is of high methodological quality. In the intervention group (2058 women), the results of infection screening and treatment for bacterial vaginosis, trichomonas vaginalis and candidiasis were reported; in the control group (2097 women), the results of the screening program for the women allocated to receive routine antenatal care were not reported. Preterm birth before 37 weeks was significantly lower in the intervention group (3% versus 5% in the control group) with a relative risk (RR) of 0.55 (95% confidence interval (CI) 0.41 to 0.75). The incidence of preterm birth for low birthweight preterm infants with a weight equal to or below 2500 g and very low birthweight infants with a weight equal to or below 1500 g were significantly lower in the intervention group than in the control group (RR 0.48, 95% CI 0.34 to 0.66 and RR 0.34; 95% CI 0.15 to 0.75, respectively).

AUTHORS' CONCLUSIONS

There is evidence that infection screening and treatment programs in pregnant women may reduce preterm birth and preterm low birthweights. Future trials should evaluate the effects of types of infection screening program, gestational ages at screening test and the costs of introducing an infection screening program.

The profile of emergency contraception users in a chlamydia prevalence study in primary care in Belgium

INTRODUCTION

We describe the use of emergency contraception (EC) and its association with sociodemographic, contraceptive and behavioural characteristics in a sample of family practice attendants in Belgium.

METHODS

The study was part of a large Chlamydia trachomatis (CT) prevalence study in general practice. Sexually active women under 40 who consulted their general practitioner for routine gynaecological care were enrolled in the study. Participants completed a questionnaire on sociodemographic variables, urogenital symptoms, sexual history and sexual behaviour, and delivered a sample for CT testing. Logistic regression analysis was performed to identify determinants of a history of EC use in women in this sample.

RESULTS

Of 815 questioned women, 23.5% had ever used EC. EC users were a heterogeneous group with respect to educational level, age and ethnicity. The use of emergency contraception was associated with the level of urbanisation, condom use, not having children yet, young age of first sexual intercourse, having had multiple partners in the past year, a history of unintended pregnancy, and current or previous STI.

DISCUSSION

Information on availability and correct use of EC, and on the need for additional testing for STI, are necessary to help primary care attendees to preserve their future reproductive health.

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.

Diagnostic Tests for Chlamydial and Gonorrheal Infections

Chlamydia trachomatis and Neisseria gonorrhoeae are the two most prevalent bacterial sexually transmitted infections reported in the United States. The purpose of this article is to review the various tests available for diagnosing C. trachomatis and N. gonorrhoeae. The nucleic acid amplification tests are preferred owing to their high sensitivity and specificity and use on specimens obtained noninvasively. Non-amplified non-culture tests, such as the DNA probe test, remain a choice for settings in which nucleic acid amplification tests are not available or affordable. Culture is recommended for use on conjunctival, oropharyngeal, and rectal specimens and in cases of suspected abuse. In addition, for gonorrhea, culture is recommended when screening in populations with a low prevalence of infection. Point-of-care tests are limited by low sensitivity and should be used for only populations unlikely to return for follow-up.