Reappraising the value of urine leukocyte esterase testing in the age of nucleic acid amplification

Prevalence of Mycoplasma genitalium and other sexually transmitted infections causing urethritis among high-risk heterosexual male patients in Estonia

BACKGROUND

We aimed to evaluate the prevalence of sexually transmitted infections (STI, including Mycoplasma genitalium, Chlamydia trachomatis, Neisseria gonorrhoeae, Trichomonas vaginalis) among high-risk heterosexual male patients and to clarify their potency to cause complaints and inflammation.

METHODS

The study group included 825 men (18.0-49.5 y) consulting andrologist at Tartu University Hospital (Estonia) due to subjectively perceived risk of STI. Patients completed STI risk behaviour questionnaire. First voided urine was analysed for white blood cells and STIs.

RESULTS

In total 193 (23.4%) patients were positive for one or multiple STI. The prevalence of C. trachomatis, M. genitalium, N. gonorrhoeae, T. vaginalis and combined STI was 14.3%, 4.4%, 2.7%, 0.7% and 1.3%, respectively. N. gonorrhoeae had the highest potency to generate inflammatory reaction in first voided urine (100%) followed by C. trachomatis (72.0%), M. genitalium (63.9%) and T. vaginalis (33.3%). N. gonorrhoeae and T. vaginalis caused the highest mean number of complaints while half of T. vaginalis cases and nearly fifth of M. genitalium and C. trachomatis cases were asymptomatic.

CONCLUSIONS

C. trachomatis has the highest prevalence among Estonian high-risk men but M. genitalium holds an important second place. Prevalence of combined STIs is low. N. gonorrhoeae has the highest potency to generate urethral inflammation followed by C. trachomatis and M. genitalium. The highest number of complaints is also associated with N. gonorrhoeae while half of T. vaginalis cases and nearly a fifth of M. genitalium and C. trachomatis cases are asymptomatic.

Leucocyte esterase dip-stick test as a point-of-care diagnostic for urogenital chlamydia in male patients: A multi-center evaluation in two STI outpatient clinics in Paramaribo and Amsterdam

BACKGROUND

Point-of-care (POC) tests are an important strategy to address the epidemic of sexually transmitted infections (STIs). The leucocyte esterase test (LET) can be used as a POC test for chlamydia. The aim of this study was to determine the diagnostic accuracy of the LET to detect urogenital chlamydia among men at STI clinics in Paramaribo, Suriname and Amsterdam, the Netherlands.

METHODS

Recruitment of patients took place in 2008-2010 in Suriname and in 2009-2010 in the Netherlands. Urine of patients was examined with the LET. The reference test was a nucleic acid amplification test (NAAT).

RESULTS

We included 412 patients in Suriname and 645 in the Netherlands. Prevalence of chlamydia in Suriname and the Netherlands was respectively 22.8 and 13.6 %. The sensitivity of the LET was 92.6 % (95 % CI = 85.3-97.0) and 77.3 % (95 % CI = 67.1-85.5) respectively, the specificity was 38.1 % (95 % CI = 32.7-43.6 %) and 58.1 % (95 % CI = 53.9-62.3) respectively. The positive predictive value was 30.6 % (95 % CI = 27.3-36.4) and 22.6 % (95 % CI = 18.0-27.7) respectively and the negative predictive value was 94.5 % (95 % CI = 89.1-97.8) and 94.2 % (95 % CI = 91.1-96.4) respectively. The kappa was respectively 0.179 and 0.176.

CONCLUSIONS

To diagnose urogenital chlamydia in men the LET performs poorly. It has a high negative but low positive predictive value. If the LET result is negative, chlamydia is accurately excluded, yet a positive result has a low predictive value. Whether the advantages of direct management based on LET outweigh the disadvantages of overtreatment is a subject for further studies.

Testing for 'threads' and leucocyte esterase in first-void urine to exclude the diagnosis of non-specific urethritis in asymptomatic men

Recent evidence suggests that asymptomatic nonspecific urethritis (NSU), which is not routinely tested for, is a clinically significant pathology.The aim of this pilot study was to determine if testing for urinary threads, leucocyte esterase (LE) or both in asymptomatic men is a good screening tool for NSU. Of the126 asymptomatic men, 8% met microscopic criteria for the diagnosis of NSU. The positive predictive value for NSU was 71% (95% confidence interval (CI): 29.3-95.5%) and the negative predictive value was 96% (95% CI: 92.8-99.5%). The absence of threads and negative LE makes urethritis highly unlikely, making urinary chlamydia (Chlamydia trachomatis) and gonorrhoea (Neisseria gonorrhoeae) testing sufficient. Incidental findings of further pathology occurred in 7%.

Using urinary leucocyte esterase tests as an indicator of infection with gonorrhoea or chlamydia in asymptomatic males in a primary health care setting

To evaluate a leucocyte esterase test as a predictor of gonorrhoea or chlamydia in asymptomatic Aboriginal males at the Central Australian Aboriginal Congress Male Clinic (Ingkintja), first-void urine samples and clinical information were collected from consecutive asymptomatic males presenting to the Ingkintja in Alice Springs between March 2008 and December 2009. Urine was tested immediately with a leucocyte esterase test dipstick and then by polymerase chain reaction for gonorrhoea and chlamydia. Among the 292 specimens from asymptomatic males, 15.4% were positive for gonorrhoea or chlamydia. In this group, compared with polymerase chain reaction result for gonorrhoea or chlamydia, leucocyte esterase test alone and in combination with age ≤35 years showed sensitivities of 66.7% and 60%, specificities of 90.7% and 94.7%, positive predictive values of 56.6% and 67.5%, negative predictive values of 93.7% and 92.8% and the area under receiver operating characteristics curve values of 0.79 and 0.85, respectively. Leucocyte esterase tests can reasonably be used as a basis for immediate empirical treatment for gonorrhoea or chlamydia in asymptomatic central Australian Aboriginal men under 35 years of age.

Advances in sampling and screening for chlamydia

Chlamydia is the most commonly diagnosed bacterial sexually transmitted infection in the developed world, with diagnosis rates continuing to increase each year. As chlamydia is largely asymptomatic, screening and treatment is the main way to detect cases and reduce transmission. Recent advances in self-collected specimens and laboratory tests has made chlamydia screening easier to implement as well as possible in nonclinical settings. This review will discuss new approaches to specimen collection and how these have expanded opportunities for reaching target populations for chlamydia screening. Furthermore, it will discuss how advanced molecular microbiological methods can be used with self-collected specimens to further our knowledge of the epidemiology of chlamydia and the dynamics of transmission.

Point-of-care tests for the diagnosis of Neisseria gonorrhoeae infection: a systematic review of operational and performance characteristics

OBJECTIVES

Systematic review of the performance and operational characteristics of point-of-care (POC) tests for the diagnosis of Neisseria gonorrhoeae.

METHODS

We searched PubMed and Embase until August 2010 using variations of the terms: 'rapid test', 'Neisseria gonorrhoeae' and 'evaluation'.

RESULTS

We identified 100 papers, 14 studies were included; nine evaluated leucocyte esterase (LE) dipsticks and three immunochromatographic strips, and two clinical audits of microscopy were identified. Of the field evaluations the gold standard was nucleic acid amplification technology in six studies and bacterial culture in the other six. In four studies, 50% or more of the patients were symptomatic. The median sensitivity of LE dipsticks was 71% (range 23-85%), median specificity was 70% (33-99%), median positive predictive value (PPV) was 19% (5-40%) and median negative predictive value (NPV) was 95% (56-99%). One LE study found a sensitivity of 23% overall, increasing to 75% in symptomatic women. LE dipsticks mostly involved three steps and took under 2 min. The median sensitivity of immunochromatographic tests (ICT) was 70% (60-94%), median specificity was 96% (89-97%), median PPV was 56% (55-97%) and median NPV was 93% (92-99%). Immunochromatic strips involved five to seven steps and took 15-30 min. Specificity of microscopy ranged from 38% to 89%.

CONCLUSIONS

ICT and LE tests had similar sensitivities, but sensitivity results may be overestimated as largely symptomatic patients were included in some studies. ICT had a higher specificity in women than LE tests. The findings highlight the need for improved POC tests for diagnosis of N gonorrhoeae and more standardised evaluations.

The prevalence of Chlamydia trachomatis infection in Australia: a systematic review and meta-analysis

BACKGROUND

Chlamydia trachomatis is a common sexually transmitted infection in Australia. This report aims to measure the burden of chlamydia infection by systematically reviewing reports on prevalence in Australian populations.

METHODS

Electronic databases and conference websites were searched from 1997-2011 using the terms 'Chlamydia trachomatis' OR 'chlamydia' AND 'prevalence' OR 'epidemiology' AND 'Australia'. Reference lists were checked and researchers contacted for additional literature. Studies were categorised by setting and participants, and meta-analysis conducted to determine pooled prevalence estimates for each category.

RESULTS

Seventy-six studies met the inclusion criteria for the review. There was a high level of heterogeneity between studies; however, there was a trend towards higher chlamydia prevalence in younger populations, Indigenous Australians, and those attending sexual health centres. In community or general practice settings, pooled prevalence for women <25 years in studies conducted post-2005 was 5.0% (95% CI: 3.1, 6.9; five studies), and for men <30 years over the entire review period was 3.9% (95% CI: 2.7, 5.1; six studies). For young Australians aged <25 years attending sexual health, family planning or youth clinics, estimated prevalence was 6.2% (95% CI: 5.1, 7.4; 10 studies) for women and 10.2% (95% CI: 9.5, 10.9; five studies) for men. Other key findings include pooled prevalence estimates of 22.1% (95% CI: 19.0, 25.3; three studies) for Indigenous women <25 years, 14.6% (95% CI: 11.5, 17.8; three studies) for Indigenous men <25 years, and 5.6% (95% CI: 4.8, 6.3; 11 studies) for rectal infection in men who have sex with men. Several studies failed to report basic demographic details such as sex and age, and were therefore excluded from the analysis.

CONCLUSIONS

Chlamydia trachomatis infections are a significant health burden in Australia; however, accurate estimation of chlamydia prevalence in Australian sub-populations is limited by heterogeneity within surveyed populations, and variations in sampling methodologies and data reporting. There is a need for more large, population-based studies and prospective cohort studies to compliment mandatory notification data.

Urine‐based testing forChlamydia trachomatisusing polymerase chain reaction, leucocyte esterase and urethral and cervical smears

The performance of Roche polymerase chain reaction (PCR) Amplicor to detect Chlamydia trachomatis in first-voided urine specimens from 422 males and 456 females attending two clinics for sexually transmitted infections was evaluated in comparison with cultures of urethral and cervical specimens. At the same time, the ability of leucocyte esterase (LE) in first-voided urine and the presence of leucocytes in urethral and cervical smears to identify C. trachomatis-infected individuals based on PCR and culture was determined. The prevalence of C. trachomatis infection was 10.9% in men and 7.7% in women. Sensitivity, specificity, positive predictive value and negative predictive value of Amplicor was 93.5%, 99.7%, 97.7% and 99.2% in males and 91.4%, 99.5%, 94.1% and 99.3% in females. All Chlamydia-infected men were identified by means of a combination of urethritis (4 leucocytes in the urethral smear) and/or a positive LE test in urine, although the specificity was only 42.2%. In women, the combination of urethritis and/or cervicitis and/or a positive LE test identified 85.7% of Chlamydia-infected patients with a specificity of 38.2%. It is concluded that a combination of urethral and/or cervical smears and LE testing of urine can be used as a screening test to select patients, especially males, for specific C. trachomatis testing.

The cost-effectiveness of screening men for Chlamydia trachomatis: a review of the literature

BACKGROUND

An important consideration in determining whether to implement or continue a program to screen men for chlamydia is its cost-effectiveness. A review of the literature on the cost-effectiveness of screening men for chlamydia could potentially provide guidance.

METHODS

An Ovid Medline search was conducted for articles published between 1990 and July 2007 using terms for cost, chlamydia, and male. This search returned 175 articles; 25 were retained after eliminating those not relevant to cost-effectiveness studies of male chlamydia screening. We added 4 articles that were in-press or are published in this issue, for a total of 29. These articles were examined for common themes and their results summarized.

RESULTS

The reviewed studies examined both proactive and opportunistic screening and included screening of risk groups and of the general population. Some older studies included enzyme immunoassays; more recent studies featured nucleic acid amplification assays. Six studies used dynamic transmission models. Fourteen studies analyzed male and female chlamydia screening interventions. Several contained sufficient data to examine the cost-effectiveness of male screening compared with female screening. Male screening was preferred to expanded female screening in 1 study. In other studies, combined male and female screening programs were cost-saving.

CONCLUSIONS

Studies comparing chlamydia screening in men with chlamydia screening in women may be the most useful for guidance to programs. The studies which compare the 2 generally have found that screening men from the general population is not preferred to screening women from the general population, although 1 study found that screening of men from risk groups can be cost-effective compared with screening women from the general population.

Should asymptomatic men be included in chlamydia screening programs? Cost-effectiveness of chlamydia screening among male and female entrants to a national job training program

OBJECTIVE

To compare the cost-effectiveness of various chlamydia screening strategies within a population of male and female youth entering a national job training program.

STUDY DESIGN

Cost-effectiveness analysis of various chlamydia screening strategies among a cohort of 4000 female and male New England job training students. Strategies for women include (a) no screening, (b) universal endocervical DNA probe screening, (c) universal urine based NAAT screening, and (d) universal endocervical NAAT screening. Strategies for men include (a) no screening, (b) selective urine NAAT screening of leukocyte esterase (LE)-positive urines, and (c) universal urine-based NAAT screening.

RESULTS

Universal endocervical NAAT screening of women and universal urine NAAT screening of men were the most effective and cost-effective strategies individually and in combination. Endocervical NAAT screening of women prevented 23 more cases of PID and saved $27,000 more than endocervical DNA probe screening. Likewise, universal urine NAAT screening of men prevented 21 more cases of PID in their female partners and saved $16,000 more than selective urine NAAT screening of LE positive men.

CONCLUSIONS

Use of a sensitive NAAT to screen both men and women for chlamydia upon entry to a National Job Training Program is cost-effective, cost-saving, and provides a public health opportunity to substantially reduce chlamydia infections among youth at risk for sexually transmitted diseases.

Performance of urine leukocyte esterase in asymptomatic male youth: another look with nucleic acid amplification testing as the gold standard for Chlamydia detection

PURPOSE

To re-evaluate the sensitivity and specificity of leukocyte esterase (LE) for screening adolescent and young adult males for Chlamydia trachomatis using a nucleic acid amplification test (NAAT) as the gold standard.

METHODS

This study was conducted at two Massachusetts Department of Youth Services sites and one Job Corps site. Recently admitted asymptomatic sexually active male youth aged 14 to 25 years (mean 16.6 years) were recruited between January 2001 and July 2003 (N = 1008). Participants provided first part voided urine specimens for testing with LE and Chlamydia NAAT. The sensitivity, specificity, and positive and negative predictive value of urine LE for identification of Chlamydia infection were determined using NAAT as the gold standard.

RESULTS

Fifty-seven (5.7%) participants were infected with Chlamydia as defined by a positive NAAT. Defining trace + as the LE cut point resulted in sensitivity and specificity of 57.9% and 78.3%, respectively. Defining 1+ as the cut point resulted in sensitivity and specificity of 47.4% and 96.1%, respectively.

CONCLUSIONS

Urine leukocyte esterase is a moderately sensitive method to screen for Chlamydia. Nevertheless, a substantial proportion of infections are not detected with LE screening. When feasible, urine NAAT provides a much more sensitive and equally noninvasive method of detecting Chlamydia. However, if LE is used as an initial screen followed by NAAT confirmation of LE positive samples, we recommend using trace LE as the cut point for positive results.

Sexually transmitted infections in male clients of female sex workers in Benin: risk factors and reassessment of the leucocyte esterase dipstick for screening of urethral infections

OBJECTIVES

(1) To assess risk factors for urethral infections with Chlamydia trachomatis, Neisseria gonorrhoeae, and Trichomonas vaginalis among male clients of female sex workers (FSWs) in Benin; (2) to study the validity of LED testing of male urine samples compared to a highly sensitive gold standard (PCR) for the diagnosis of urethral infections with the organisms cited above.

METHODS

Male clients of FSWs (n=404) were recruited on site at prostitution venues in Cotonou, Benin, between 28 May and 18 August 1998. A urine sample was obtained from each participant just before he visited the FSW, and tested immediately using a leucocyte esterase dipstick (LED) test. It was then tested for HIV using the Calypte EIA with western blot confirmation, and for C. trachomatis, N. gonorrhoeae, and T. vaginalis by PCR. After leaving the FSW's room, participants were interviewed about demographics, sexual behaviour, STI history and current symptoms and signs, and were examined for urethral discharge, genital ulcers, and inguinal lymphadenopathies.

RESULTS

STI prevalences were: C. trachomatis, 2.7%; N. gonorrhoeae, 5.4%; either chlamydia or gonorrhoea 7.7%; T. vaginalis 2.7%; HIV, 8.4%. Lack of condom use with FSWs and a history of STI were independently associated with C. trachomatis and/or N. gonorrhoeae infection. Over 80% of these infections were in asymptomatic subjects. The overall sensitivity, specificity, positive and negative predictive values of the LED test for detection of either C. trachomatis or N. gonorrhoeae were 48.4%, 94.9%, 44.1%, and 95.7%, respectively. In symptomatic participants (n=22), all these parameters were 100% while they were 47.4%, 94.7%, 37.5%, and 96.4% in asymptomatic men (n=304).

CONCLUSIONS

Since most STIs are asymptomatic in this population, case finding programmes for gonorrhoea and chlamydia could be useful. The performance characteristics of the LED test in this study suggest that it could be useful to detect asymptomatic infection by either C. trachomatis or N. gonorrhoeae in high risk men.

Primary care management of sexually transmitted urethritis in adolescent males

PURPOSE

To describe current knowledge about diagnosis, screening, and treatment of sexually transmitted urethritis among adolescent and young adult males.

DATA SOURCES

Current research, systematic reviews, consensus guidelines and the author's clinical experience.

CONCLUSIONS

Urethritis, the most common sexually transmitted syndrome in young males, is most frequently caused by Chlamydia trachomatis and/or Neisseria gonorrhea. Symptoms include dysuria and penile discharge, although up to 50% of males are asymptomatic. Risky sexual behaviors and lack of access to healthcare increase incidence of this infection. Transmission to female partners can lead to pelvic inflammatory disease, infertility, and neonatal infection.

IMPLICATIONS FOR PRACTICE

Young males with urethritis must be treated as soon as diagnosis is established. Consensus guidelines exist for diagnosis and treatment of gonococcal and non-gonococcal urethritis. Careful patient education is necessary to ensure successful treatment. Prevention of repeat infections requires partner treatment and detailed education about safer sexual practices. Improved access to preventive services for young males should be a healthcare priority.

The accuracy and efficacy of screening tests for Chlamydia trachomatis: a systematic review

Screening women for lower genital tract infection with Chlamydia trachomatis is important in the prevention of pelvic inflammatory disease, ectopic pregnancy and infertility. This systematic review aims to state clearly which of the available diagnostic tests for the detection of C. trachomatis would be most effective in terms of clinical effectiveness. The review included all studies published from 1990 onward that evaluated diagnostic tests in asymptomatic, young, sexually active populations. Medline and Embase were searched electronically and key journals were hand-searched. Further studies were identified through the Internet and contact with experts in the field. All studies were reviewed by two reviewers and were scored by Irwig's assessment criteria. Additional quality assessment criteria included a documented sexual history and recording of previous chlamydial infection. The reviews were subjected to meta-analysis and meta-regression. The 30 studies that were included examined three types of DNA-based test--ligase chain reaction (LCR), PCR and gene probe--as well as enzyme immuno-assay (EIA). The results showed that while specificities were high, sensitivities varied widely across the tests and were also dependent on the specimen tested. Pooled sensitivities for LCR, PCR, gene probe and EIA on urine were 96.5%, 85.6%, 92% and 38%, respectively, while on cervical swabs the corresponding sensitivities of PCR, gene probe and EIA were 88.6%, 84% and 65%. Meta-analysis demonstrated that DNA amplification techniques performed best for both urine and swabs in low prevalence populations. We conclude that nucleic acid amplification tests used on non-invasive samples such as urine are more effective at detecting asymptomatic chlamydial infection than conventional tests, but there are few data to relate a positive result with clinical outcome.

Urine-based screening for Chlamydia trachomatis in men attending sexually transmitted disease clinics

BACKGROUND

Nucleic acid-amplified tests for Chlamydia trachomatis are accurate but costly. Screening strategies for asymptomatic men are needed.

GOAL

To assess C trachomatis screening strategies for asymptomatic males.

STUDY DESIGN

Men attending a sexually transmitted disease clinic were tested for C trachomatis with ligase chain reaction and culture, and for urethral inflammation with urine leukocyte esterase and urethral Gram stain.

RESULTS

C trachomatis prevalence was 5.5% among 1,625 asymptomatic men. Ligase chain reaction increased detection by 49% among men without urethral inflammation. An age of younger than 25 years and urethral inflammation were associated with positive ligase chain reaction results. The negative predictive value of urine leukocyte esterase was highest among older men, but urethral Gram stain was equally sensitive in predicting infection regardless of age. An age of younger than 30 years or urethral inflammation identified the highest proportion of infections (92%) and reduced the percentage of men screened by 43%.

CONCLUSIONS

Urine ligase chain reaction increased C trachomatis detection, particularly among men without urethral inflammation. Testing all asymptomatic men younger than 30 years is optimal, whereas negative urine leukocyte esterase or urethral Gram stain results in men 30 years or older support no testing.

Diagnosis and treatment of common sexually transmitted diseases in women

Chlamydia trachomatis and Neisseria gonorrhoeae are 2 very common sexually transmitted organisms, whose clinical manifestations in women can range from an asymptomatic carrier state to active pelvic inflammatory disease with known serious sequelae, including chronic pelvic pain, infertility, and ectopic pregnancy. The economic and clinical burden of these 2 infectious organisms are significant in the sexually active population. New developments in diagnosis and treatment of these infections raise great hope that substantial reduction in morbidity and disease prevalence rates can be achieved. Herpes simplex virus is probably better publicized and more feared in the sexually active population, and is far more prevalent than previously recognized; fortunately, however, it is not generally associated with significant morbidity. This article will review the current diagnoses and treatments of these conditions and consider some of the issues surrounding the impact of screening asymptomatic sexually active individuals. The treatment guidelines will emphasize the 1998 Guidelines for Treatment of Sexually Transmitted Diseases from the Centers for Disease Control and Prevention.