Chlamydial infection during trachoma monitoring: are the most difficult-to-reach children more likely to be infected?

OBJECTIVES: During mass antibiotic distributions for trachoma, certain individuals are difficult to locate and go untreated. These untreated individuals may serve as a source of community reinfection. The importance of this difficult-to-locate, untreated population is unclear. We sought to determine whether individuals who are difficult to locate were more likely to be infected with ocular chlamydia than those who were easier to locate. METHODS: We monitored 12 Ethiopian communities 1 year after a third annual mass azithromycin treatment for trachoma. Conjunctival swabbing for chlamydial RNA was performed in a random sample of children from each community. If insufficient numbers of children were enrolled on the first monitoring day, we returned on subsequent days. RESULTS: Of the 12 communities, 10 required more than one monitoring day. On average, 16.1% (95% CI 7.9-30.0) of children were enrolled after the initial day. Evidence of chlamydia was found in 7.1% (95% CI 2.7-17.4) of 0- to 9-year-old children. No ocular swabs collected after the initial day were positive for chlamydial RNA. Children examined after the initial monitoring day were significantly less likely to have ocular chlamydial infection than children seen on the initial day; Mantel-Haenszel common OR = 0 (95% CI 0-0.77). CONCLUSIONS: In a setting of repeated annual mass azithromycin treatments, after approximately 80% of individuals have been located in a community, extra efforts to find absent individuals may not yield significantly more cases of ocular chlamydia.

Efecto de un programa de ejercicio aeróbico en indicadores inmunológicos y el consumo máximo de oxígeno en personas con SIDA / Effect of an aerobic exercise program on immune indices and maximal oxygen consumption in AIDS patients

El propósito de este estudio fue demostrar el efecto de un programa de ejercicio aeróbico en indicadores inmunológicos y el consumo máximo de oxígeno (VO2max) de personas con sida. Participaron 10 hombres en el grupo experimental y 4 en el control. Se realizó durante 12 semanas ejercicio en bicicleta estática a una intensidad promedio del 70-85 por ciento VO2max. Al inicio y al final del programa se midieron varios indicadores inmunológicos (conteo de células CD4, células CD8, células CD3 y carga viral) y el VO2max. No se encontraron diferencias significativas en ninguno de los indicadores inmunológicos. El conteo de células CD8 y CD3 disminuyó solamente en el grupo experimental. Se encontró una tendencia de aumento del VO2max, el grupo experimental tuvo el mayor porcentaje de cambio (+31.83 por ciento). A pesar de que no se encontraron cambios estadísticamente significativos; no se detectaron efectos perjudiciales del ejercicio aeróbico en la condición clínica de los participantes (AU)

Prevalence of Chlamydia trachomatis and Neisseria gonorrhoeae in Turkey among men With urethritis.

BACKGROUND: Chlamydia trachomatis and Neisseria gonorrhoeae are known to cause urethritis. However, only a small number of studies in Eastern European countries have investigated the causes of urethritis. GOALS: To determine the prevalence of C trachomatis and N gonorrhoeae among men with symptomatic urethritis in Istanbul, Turkey, and to determine whether contact with a commercial sex worker increased the likelihood of chlamydial infections. STUDY DESIGN: Men with a diagnosis of urethritis at the Istanbul Faculty of Medicine were screened for C trachomatis and N gonorrhoeae by Abbott's ligase chain reaction (LCR) using either urethral swabs or first-void urine. N gonorrhoeae cultures were done on a subset of these patients. RESULTS: The study enrolled 813 men. All of the men denied condom use during their previous sexual exposures. The overall prevalence of C trachomatis, as determined by LCR, was 15.7%. Only 192 patients were screened for both organisms. N gonorrhoeae prevalence was 9.4%. There was no difference in the chlamydia prevalence between men who had contact with commercial sex workers (CSWs) and men who had no such contact (15.3% versus 17.2%). However, clients of foreign CSWs were more likely to have chlamydia than clients of registered Turkish CSWs. CONCLUSIONS: C trachomatis and N gonorrhoeae are commonly found in Turkish men with urethritis. The findings did not show more chlamydial infection among men who had contact with CSWs than among men who had no such contact. The failure to use condoms among these men must be addressed.

Enhancing the specificity of the COBAS AMPLICOR CT/NG test for Neisseria gonorrhoeae by retesting specimens with equivocal results.

The COBAS AMPLICOR CT/NG test for Neisseria gonorrhoeae cross-reacts with certain strains of nonpathogenic Neisseria species. In some strains, the target sequence is identical to that of N. gonorrhoeae, whereas other strains have a small number of mismatches within the regions recognized by the primers or probe used in the COBAS AMPLICOR NG test. These cross-reactive strains are occasionally present in urogenital specimens, causing false-positive results in the COBAS AMPLICOR NG test. Analysis of the data generated in a large multicenter clinical trial showed that 2.9% of the specimens gave signals between A(660)s of 0.2 and 3.5 but that one-half of these equivocal specimens did not contain N. gonorrhoeae. Most of these equivocal specimens were correctly classified as true positive or true negative by retesting in duplicate and defining a PCR-positive result as two of three results with an A(660) of > or =2.0. If specimens had been classified as positive or negative based on a single test result using a cutoff of an A(660) of 0.2, specificity would have ranged from 96.2 to 98.9% depending on specimen type, sex, and presence of symptoms. By employing the equivocal zone-retesting algorithm, specificity increased to 98.6 to 99.9% with little effect (0.1 to 4.9% decrease) on sensitivity in most specimen types, enabling the test to achieve a positive predictive value of at least 90% in populations with a prevalence of 4% or higher. In lower-prevalence populations, the test could be used to screen for presumptive infections that would have to be confirmed by an independent test.

Pooling of Chlamydia laboratory tests to determine the prevalence of ocular Chlamydia trachomatis infection.

With the Global Elimination of Trachoma by 2020 program underway, it has become increasingly important to identify the prevalence of ocular chlamydia infection in communities. DNA amplification tests are the gold standard, but are prohibitively expensive. In the present paper, we investigate whether pooling multiple specimens into a single test is feasible. The conjunctivae of 170 children in western Nepal were examined and swabbed. The prevalence of chlamydial infection was estimated in two ways using the ligase chain reaction: by testing all 170 specimens individually, and by testing 34 pools of 5 specimens each. We show that the confidence interval for 34 pooled specimens approaches that of doing all 170 specimens as the prevalence decreases. We also determine the optimal number of specimens to pool into a single test to minimize the confidence interval of the estimate. If the population prevalence is expected to be around 10%, then 14 specimens should be pooled per test. Even at 50% prevalence, costs can be reduced by pooling two samples per test.

Multicenter evaluation of the BDProbeTec ET System for detection of Chlamydia trachomatis and Neisseria gonorrhoeae in urine specimens, female endocervical swabs, and male urethral swabs.

The performance of the Becton Dickinson BDProbe Tec ET System Chlamydia trachomatis and Neisseria gonorrhoeae Amplified DNA Assays (BD Biosciences, Sparks, Md.) was evaluated in a multicenter study. Specimens were collected from 2,109 men and women, with or without symptoms, attending sexually transmitted disease, family planning, and obstetrics and gynecology clinics. Both swab and urine samples were collected, and the results obtained from 4,131 specimens were compared to those from culture and the LCx nucleic acid amplification test (Abbott Industries, Abbott Park, Ill.). PCR and cytospin of the culture transport medium with chlamydia direct fluorescent antibody staining were used to adjudicate chlamydia culture-negative results. Sensitivity and specificity were calculated both with and without use of the amplification control (AC), with little apparent difference in the results. Without the AC result, sensitivity for C. trachomatis and N. gonorrhoeae were 92.8 and 96.6%, respectively, for cervical swabs and 80.5 and 84.9% for urine from women. C. trachomatis and N. gonorrhoeae sensitivities were 92.5 and 98.5%, respectively, for male urethral swabs and 93.1 and 97.9% for urine from men. This amplified DNA system for simultaneous detection of chlamydial and gonococcal infections demonstrated superior sensitivity compared to chlamydia culture and has performance characteristics comparable to those of other commercially available nucleic acid-based assays for these organisms.

Multicenter evaluation of AMPLICOR and automated COBAS AMPLICOR CT/NG tests for Neisseria gonorrhoeae.

The fully automated COBAS AMPLICOR CT/NG and semiautomated AMPLICOR CT/NG tests were evaluated in a multicenter trial for their ability to detect Neisseria gonorrhoeae infections. Test performance compared to that of culturing was evaluated for 2,192 matched endocervical swab and urine specimens obtained from women and for 1, 981 matched urethral swab and urine specimens obtained from men. Culture-negative, PCR-positive specimens that tested positive in a confirmatory PCR test for an alternative target sequence within the N. gonorrhoeae 16S rRNA gene were considered to be true positives. The overall prevalences of gonorrhea were 6.6% in women and 20.1% in men. The COBAS AMPLICOR and AMPLICOR formats yielded concordant results for 98.8% of the specimens and exhibited virtually identical sensitivities and specificities. The results that follow are for the COBAS AMPLICOR format. With the infected patient as the reference standard, the resolved sensitivities of PCR were 92.4% for endocervical swab specimens and 64.8% for female urine specimens. There were no significant differences in these rates between women with and without symptoms. Among symptomatic men, COBAS AMPLICOR sensitivities were 94.1% for urine and 98.1% for urethral swabs; for asymptomatic men, the results were 42.3 and 73.1%, respectively. In comparison, the sensitivities of culturing were 84.8% for endocervical specimens, 92.7% for symptomatic male urethral specimens, and only 46.2% for urethral specimens obtained from asymptomatic men. When PCR results were analyzed as if only a single test had been performed on a single specimen type, the resolved sensitivity was always higher. The resolved specificities of PCR were 99.5% for endocervical swab specimens, 99.8% for female urine specimens, 98.9% for male urethral swab specimens, and 99.9% for male urine specimens. The internal control revealed that 2.1% of specimens were inhibitory when initially tested. Nevertheless, valid results were obtained for 99.2% of specimens because 60.0% of the inhibitory specimens were not inhibitory when a second aliquot was tested. The COBAS AMPLICOR CT/NG test for N. gonorrhoeae exhibited high sensitivity and specificity with urethral swab and urine specimens from men and endocervical swab specimens from women and thus is well suited for diagnosing and screening for N. gonorrhoeae infection.

Reexamining the prevalence of Chlamydia trachomatis infection among gay men with urethritis: implications for STD policy and HIV prevention activities.

BACKGROUND: Evidence of an STD-HIV interaction and the availability of noninvasive urine-based screening tests have resulted in an increased focus on chlamydial infections in men. GOAL: To evaluate the prevalence of chlamydial infections among men with urethritis at the San Francisco City Clinic (SFCC). STUDY DESIGN: In 1997, male SFCC patients diagnosed with urethritis were tested for chlamydia using urine-based ligase chain reaction and for gonorrhea using urethral culture. RESULTS: Gonorrhea was identified in 45% of men who have sex with men (MSM) versus 26% of men who have sex with women (MSW). Among men with gonorrhea, chlamydia coinfection was found among 15.2% of MSM and 8.4% of MSW. Among men with nongonococcal urethritis, 18% and 20% of MSM and MSW had chlamydial infection, respectively. Young age was associated with chlamydial infection in MSM. CONCLUSION: After a period of low chlamydial infection rates in MSM during the pre-AIDS era, infection rates are increasing among this population. SFCC's revised clinical practice guidelines include chlamydia testing of MSM with urethritis.

Multicenter evaluation of the AMPLICOR and automated COBAS AMPLICOR CT/NG tests for detection of Chlamydia trachomatis.

The fully automated COBAS AMPLICOR CT/NG and semiautomated AMPLICOR CT/NG tests were evaluated in a multicenter trial for the ability to detect Chlamydia trachomatis infections. Test performance compared to that of culture was evaluated for 2,236 matched endocervical swab and urine specimens obtained from women and for 1,940 matched urethral swab and urine specimens obtained from men. Culture-negative, PCR-positive specimens that tested positive in a direct fluorescent-antibody test or in a confirmatory PCR test for an alternative target sequence were resolved as true positives. The overall prevalences of chlamydia were 2.4% in women and 7.2% in men. The COBAS AMPLICOR and AMPLICOR formats yielded concordant results for 98.1% of the specimens. With the infected patient as the reference standard, the resolved sensitivities of COBAS AMPLICOR were 89.7% for endocervical swab specimens, 89.2% for female urine specimens, 88.6% for male urethral swab specimens, and 90.3% for male urine specimens. When results were analyzed as if only a single test had been performed on a single specimen type, the resolved sensitivity was always higher. The resolved specificities of PCR were 99.4% for endocervical swab specimens, 99.0% for female urine specimens, 98.7% for male urethral swab specimens, and 98.4% for male urine specimens. The internal control revealed that 2.4% of the specimens were inhibitory when initially tested. Nevertheless, valid results were obtained for 98.6% of the specimens because 59.1% of the inhibitory specimens were not inhibitory when a second aliquot was tested. The COBAS AMPLICOR and AMPLICOR CT/NG tests for C. trachomatis exhibited equally high sensitivity and specificity with both urogenital swab and urine specimens and thus are well suited for screening for C. trachomatis infection.

Chronic follicular conjunctivitis associated with Chlamydia psittaci or Chlamydia pneumoniae.

We determined whether patients with chronic conjunctivitis in whom direct fluorescent antibody (DFA) tests revealed genus-specific chlamydial antigens (but not species-specific Chlamydia trachomatis antigens) were infected with Chlamydia psittaci or Chlamydia pneumoniae. Patients were divided into a case group of possible non-trachomatis chlamydial conjunctivitis and a control group of nonchlamydial conjunctivitis on the basis of examination and DFA testing. Species-specific primers were used to amplify C. trachomatis, C. psittaci, and C. pneumoniae DNA with polymerase chain reaction (PCR). Four (27%) of 15 samples from the case group were positive for C. psittaci or C. pneumoniae DNA, whereas none of 24 control samples were positive. Sequencing revealed a C. pneumoniae, an avian C. psittaci, and two mammalian C. psittaci strains. A short course of oral antibiotic treatment appears to be inadequate for patients with non-trachomatis chlamydial conjunctivitis. Ocular infections due to C. pneumoniae and C. psittaci may be more common than previously recognized and can be identified by DFA and PCR.

Can serology diagnose upper genital tract Chlamydia trachomatis infections? Studies on women with pelvic pain, with or without chlamydial plasmid DNA in endometrial biopsy tissue.

BACKGROUND: Upper genital tract chlamydial infections in women are on the increase, and serology might be a convenient tool for diagnosis. Evaluations of this approach are needed in women with or without microbiologic evidence of organisms in the upper genital tract. GOALS: To compare the results of antibody assays with cervical culture and upper genital tract histopathology in women with pelvic pain and chlamydial plasmid DNA in endometrial biopsies. STUDY DESIGN: Chlamydia trachomatis plasmid DNA was detected by polymerase chain reaction (PCR) on extracted deparaffinized endometrial biopsy tissue. Five antichlamydial antibody assays were performed measuring total antibodies or immunoglobulin G (IgG), IgM, and IgA classes on sera from 14 women with plasmid DNA as well as 31 without plasmid DNA. RESULTS: Accepting the presence of plasmid DNA as the gold standard, no single test had total diagnostic accuracy. The best sensitivity and specificity occurred with the following assays: whole inclusion fluorescence (WIF) (100% and 80.6%); microimmunofluorescence IgM (MIF IgM) (78.6% and 93.6%); and heatshock protein-60 enzyme immunoassay (42.9% and 100%). Although recombinant anti-lipopolysaccharide enzyme-linked immunosorbent assays measured anti-chlamydial antibodies in a large proportion of these women, specificity was low. The sensitivity and specificity of cervical culture was 28.6% and 100% and of endometrial histopathology was 71.4% and 48.4%. Analysis of patient serological profiles suggested that and 6 women without plasmid DNA may have been cases that were missed by PCR. CONCLUSIONS: Evaluations of assays to diagnosis Chlamydia trachomatis upper genital tract infections could use the presence of organisms or their markers in the upper genital tract as a standard of comparison. Some of these serological assays, such as WIF or MIF IgM, may be helpful in diagnosis, but more studies are needed.

Evaluation of the Vidas Chlamydia test to detect and verify Chlamydia trachomatis in urogenital specimens.

The Vidas Chlamydia test (CHL) is an automated enzyme-linked immunofluorescence assay for the detection of Chlamydia trachomatis. Positive and equivocal results are confirmed with a blocking assay. A mouse monoclonal antibody directed against the chlamydial lipopolysaccharides was used for the test. The CHL assay is widely used in Europe, but U.S. experience with it is limited. Three clinical test sites (The Arlington Hospital, Arlington, Va., Indiana University, Indianapolis, and the University of California, San Francisco) compared CHL with tissue culture (TC) for the identification of chlamydia in urogenital specimens (2,453 females and 850 males). True positives (TP) were defined as either TC positive or TC negative and CHL positive by a positive direct fluorescent-antibody assay or PCR test. Overall prevalence was 5.5% for females, 10.3% for male urethral swabs, and 10.7% for combined male TC urethral swabs and CHL with first catch urine (FCU) specimens. Compared to TP, CHL and TC had sensitivities of 89.6 and 94.1% with female cervical swabs and 90.9 and 86.4% with male urethral swabs, respectively. CHL sensitivity was 81.2 for male FCU specimens and 77.7% for matching male TC swabs. There were relatively few false-positive results, with all specificities being >99.4%. With the blocking assay, Vidas CHL specificity was >99.7%. However, male FCU specimen sensitivity was compromised because 9.2% (7 of 76) of the TP were initially positive but were not confirmed. An improvement in the Vidas blocking assay is needed before we can recommend its use with male urine. Alternatively, one could argue that the specificity of the test is so high that a confirmatory assay is not needed. For male and female swabs, the Vidas CHL assay has a performance that is similar to that of TC.

Chloracne in the 1990s.

BACKGROUND: Chloracne is a disease associated with toxicity of halogenated compounds used in some industrial processes. A patient affected by chloracne led us to study a total of nine cases from a single factory. METHODS: We studied the clinical features of nine patients exposed chronically to chlorobenzenes. On all of them blood samples were drawn and biopsies of affected skin and liver were taken. Their work environment was visited and studied. RESULTS: All nine patients were men and had polymorphic skin lesions, characterized mainly by comedones and cysts. They had chronic conjunctivitis and seven had cysts in the Meibomian glands. All of them had polyneuropathy and liver damage and seven had hypertriglyceridemia. Compounds known to cause chloracne were found in exceedingly high concentrations in the water used in the workplace. CONCLUSIONS: Every patient exposed to halogenated compounds with the cutaneous manifestations of chloracne should be carefully investigated for systemic complications (such as ophthalmic, neuropathic, hepatic, and lipoprotein abnormalities).

Is urine leukocyte esterase test a useful screening method to predict Chlamydia trachomatis infection in women?

We evaluated the use of the leukocyte esterase test (LET) on first-catch urine specimens from women as a screening test to predict infection with Chlamydia trachomatis. For diagnosis, we used Abbott's ligase chain reaction (LCR) on urine specimens and isolation by tissue culture (TC) on cervical brushes. Of 4,053 women attending sexually transmitted disease and family planning clinics, 4.3% (n = 174) were positive by TC and 5.9% (n = 239) were positive by LCR. When LET was compared to TC, the sensitivity, specificity, positive predictive value, and negative predictive value were 54.0, 67.0, 6.8, and 97.0%, respectively. The corresponding performance of LET versus LCR was 53.1, 67.3, 10.1, and 95.8%. Almost half of the laboratory-confirmed chlamydial infections were negative by LET. The low specificity probably reflects multiple causes of pyuria in women and results in a low positive predictive value. LET is neither sensitive nor specific as a predictor of chlamydial infection and cannot be recommended for use as a screening test for C. trachomatis with first-catch urine samples from females from low- or moderate-prevalence populations.

Noninvasive tests for diagnosis of Chlamydia trachomatis infection: application of ligase chain reaction to first-catch urine specimens of women.

Ligase chain reaction (LCR) to diagnose Chlamydia trachomatis infection was evaluated using first-catch urine (FCU) specimens from 4053 women. Results were compared with those of cell culture (TC) isolation from cervix (all) and urethra (2812 women). The reference standard was TC positivity or positive LCR for chlamydial plasmid DNA confirmed by direct fluorescent antibody test or LCR for another chlamydial gene. Compared with cervical culture, LCR was 88.2% sensitive and 100% specific. Adding urethral culture increased TC sensitivity from 67.1% to 74% and reduced LCR sensitivity to 85.9%. The prevalence of chlamydial infection was 5% (142/2812) by the dual culture system and 5.9% (165/2812) by LCR on FCU specimens. LCR on FCU specimens is highly sensitive and specific for diagnosing chlamydial infection. It is more sensitive than TC and may well present public health authorities with a useful noninvasive screening test for chlamydial infection in asymptomatic women.

Detection of Chlamydia trachomatis in first catch urine samples from symptomatic and asymptomatic males.

BACKGROUND AND OBJECTIVES: Non-invasive tests are needed to detect Chlamydia trachomatis in the genital tract. For men, urine appears to be a useful specimen for chlamydial antigen or nucleic acid detection. GOAL OF THIS STUDY: To evaluate enzyme immunoassays (EIA) for chlamydial antigens in first catch urine (FCU) from symptomatic and asymptomatic men. STUDY DESIGN: We conducted five different studies; FCUs and urethral swabs were collected from 1,341 symptomatic and 816 asymptomatic males. Four EIAs (SureCell, Chlamydiazyme, MicroTrak and IDEIA) were tested on the FCU sediments. RESULTS: Prevalence of chlamydia by tissue culture isolation was 6% for asymptomatic and 14% for symptomatic men. With symptomatic males, the EIA sensitivities and specificities were: SureCell 85% and 97%, IDEIA 82% and 98%, MicroTrak 86% and 99%, and Chlamydiazyme 91% and 95%. For asymptomatic men, Chlamydiazyme sensitivity was 35% with frozen urine vs 77% with fresh urine. Overall, tissue culture sensitivity was about 90%. CONCLUSION: EIA results on FCU sediments are comparable to that of tissue culture isolation on urethral swabs. In many settings, FCU may be the specimen of choice for diagnosing chlamydial infections in men.

Evaluation of urine-based screening strategies to detect Chlamydia trachomatis among sexually active asymptomatic young males.

OBJECTIVE: To evaluate the performances of diagnostic screening tests alone or in combination to detect asymptomatic chlamydial urethral infection in young males. DESIGN: Comparisons of the performance profiles of the following chlamydia screening strategies were done: urethral culture; identification of polymorphonucleocytes (PMNs) on spun first-void urine (FVU); urinary leukocyte esterase test (LET) on unspun FVU; chlamydial enzyme immunoassay (EIA) applied to FVU sediment; combining LET on unspun FVU followed by EIA with or without direct fluorescent antibody (DFA) confirmation on FVU sediment; and combining PMNs on spun FVU followed by EIA with or without DFA confirmation. SETTING: General clinics at a youth detention center, university-based teen clinic, college health service, and a military screening clinic. PATIENTS: A total of 618 males aged 12 to 35 years (mean, 17 years) were recruited as a convenience sample; site participation rates ranged from 50% to 80%. Eligible subjects were sexually active, denied symptoms of urethritis, and had taken no antibiotics in the prior 2 weeks. MAIN OUTCOME MEASURES: Sensitivity, specificity, and positive and negative predictive values of each test strategy's ability to detect Chlamydia trachomatis infection, and cost to confirm each positive case. RESULTS: With a 7% prevalence of chlamydial infection, tissue culture had a sensitivity of only 61%. However, two strategies yielded significantly better performance profiles compared with the others: EIA confirmed by DFA test with a sensitivity of 84%, a specificity of 100%, and a cost to identify each positive case of $434; and PMNs followed by EIA confirmed by DFA test with a sensitivity of 78%, a specificity of 100%, and a cost to identify each positive case of $199. The LET followed by EIA-DFA had a similar performance profile to the PMN test strategies. CONCLUSIONS: A combination of a nonspecific screening of FVU for PMNs or LET followed by specific testing with EIA with DFA confirmation has superior clinical and cost-effective performance for detecting asymptomatic C trachomatis urethritis in young males compared with other strategies. However, an evaluation of the medical, fiscal, and psychological benefits and risks associated with a specific screening strategy for sexually transmitted diseases must be made before adopting a specific strategy for a particular population.

Evaluation of chlamydiazyme enzyme immunoassay for detection of Chlamydia trachomatis in urine specimens from men.

Paired first-voided urine and urethral swab specimens were collected from 540 men attending sexually transmitted disease clinics in three geographic locations. Urine specimens were tested for the presence of Chlamydia trachomatis by commercial enzyme immunoassay (Chlamydiazyme), and the results were compared with those of urethral swab cultures. Overall prevalence of urethral C. trachomatis by culture was 14%, and the Chlamydiazyme assay had an overall sensitivity of 83%, a specificity of 96%, a positive predictive value of 76%, and a negative predictive value of 97%. Sensitivity was greater (94%) in those culture-positive samples with a high antigen load (> or = 20 inclusion-forming units per coverslip) than those with a lower antigen load (68%). Assay of urine specimens from men attending sexually transmitted disease clinics by Chlamydiazyme appears to be a reliable, noninvasive method of detection of C. trachomatis infection, and further evaluation of its performance in asymptomatic and low-prevalence populations is indicated.