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

Evaluation of the Predictive Value of Urine Leukocyte Esterase Test in Chlamydia trachomatis and Neisseria gonorrhoeae Infection Among Males Attending HIV/STI Clinics in Guangdong Province, China

Leukocyte esterase test (LET) detection is a simple and inexpensive test performed by urinalysis. This study investigated the predictive value of LET for Chlamydia trachomatis (CT) and Neisseria gonorrhoeae (NG) infection among men attending HIV and sexually transmitted infection (HIV/STI) clinics in Guangdong Province, China. A total of 5,509 urine samples were collected from HIV and sexually transmitted infection clinics in Guangdong Province between 2017 and 2019. Specimens from 5,464 males were tested by both LET and nucleic acid amplification test (NAAT). Of 5,464 males, 497 (9.1%) tested positive for CT or NG by NAAT, with respective prevalence rates of 6.4% (95% confidence interval [95% CI]: 5.8-7.1%) and 3.8% (95% CI: 3.3-4.3%), including 1.2% (95% CI: 0.9-1.4%) co-infected. Compared to the HIV-negative individuals, individuals living with HIV tend to have a higher prevalence of CT, NG and co-infection with CT and NG. The LET sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) for CT were 46.4% (95% CI: 41.2-51.7%), 92.0% (95% CI: 91.2-92.7%), 28.4% (95% CI: 24.8-32.1%), and 96.1% (95% CI: 95.6-96.7%), respectively. The LET sensitivity, specificity, PPV, and NPV for NG were 68.4% (95% CI: 62.1-74.7%), 91.8% (95% CI: 91.1-92.6%), 25.0% (95% CI: 21.4-28.5%), and 98.7% (95% CI: 98.3-99%), respectively. Compared to the HIV-negative individuals, higher sensitivity and specificity were observed for HIV-positive individuals, but there was no statistical difference. The incremental cost-effectiveness ratio (ICER) using economic costs per additional person CT positive and NG positive was -$238.74 and -$145.60 compared with LET positive, respectively. LET is a cost-effective test and will be valuable for predicting CT and NG infection, which is highly prevalent in low- and middle-income countries.

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.

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.

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.

Chlamydia and gonorrhea screening using urine-based nucleic acid amplification testing among males entering New York City jails: a pilot study

This article describes a pilot screening program to detect Chlamydia trachomatis (Ct) and Neisseria gonorrhoeae (Ng) sexually transmitted infections (STIs) in adolescent and adult males newly incarcerated in New York City jails using urine-based nucleic acid amplification technology (NAAT). Between December 8 and 22, 2003, 2,417 males were tested; 162 (6.7%) were found positive for Ct and/or Ng STIs, with 138 (86.8%) exhibiting no STI signs or symptoms and 102 (63%) treated prior to jail release. Younger age, positive urine leukocyte esterase test, and ≥11 recent sex partners were predictors of STI. Urine-based screening and treatment was feasible in this setting and identified STI that would otherwise have been undetected. Jails may thus be important venues for targeted male STI screening.

Examining the development and sexual behavior of adolescent males

A careful examination of young men's sexuality by health professionals in pediatrics, primary care, and reproductive health is foundational to adolescent male sexual health and healthy development. Through a review of existing published data, this article provides background and a developmental framework for sexual health services for adolescent boys. The article first defines and provides an overview of adolescent boys' sexual health, and then discusses developmentally focused research on the following topics: (1) early romantic relationships and the evolution of power and influence within these relationships; (2) developmental "readiness" for sex and curiosity; (3) boys' need for closeness and intimacy; (4) adopting codes of masculinity; (5) boys' communicating about sex; and (6) contextual influences from peers, families, and providers. This article concludes by examining the implications of these data for sexual health promotion efforts for adolescent males, including human papillomavirus vaccination.

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.

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.