***TASK*** the task is to summarize an input biomedical literature in six sentences 
    ***INPUT*** the input is a biomedical literature 
    ***OUTPUT*** the output is the summary of an input biomedical literature in six sentences 
    ***DOCUMENTATION*** 
    ***EXAMPLES*** 
    Input: Background and Objectives A quick and highly sensitive diagnostic test would be valuable in the diagnosis of Chlamydia trachomatis . Goal of this Study We compared a new polymerase chain reaction ( PCR ) technique to Chlamydiazyme ( Abbott , North Chicago , IL ) in the detection of male chlamydial urethritis , and evaluated the performance of PCR on urine sample s. Study Design Urethral sample s for analysis by PCR and Chlamydiazyme were obtained from 474 unselected patients attending a sexually transmitted diseases ( STD ) clinic . Urine sample s were analyzed by PCR from 362 of these patients . Results Twenty seven ( 5.7 % ) urethral sample s were positive by Chlamydiazyme , while 64 ( 13.5 % ) were positive by PCR . After resolution of discrepant results , the sensitivity of PCR  on urethral swabs was 98.4 % and the specificity was 99.0 % , with positive and negative predictive values of 93.8 % and 99.8 % , respectively . These same measures for Chlamydiazyme were 43.5 % , 100 % , 100 % , and 92.2 % , respectively . The sensitivity of PCR  on urine sample s was 87.1 % , the specificity was 98.0 % , and the positive and negative predictive values were 90.0 % and 97.4 % , respectively . Conclusions This PCR test is more sensitive than Chlamydiazyme in detecting male urethral chlamydial infections in an STD clinic population , and appears to be equally efficacious on urethral swabs and urine sample OBJECTIVE The purpose of this study was to examine the performance of different test types , specimen sources , and collection methods for screening of genital Chlamydia trachomatis infection in young women . STUDY DESIGN Asymptomatic women aged 16 to 25 years collected their own vaginal swabs and a first-voided urine specimen ; a clinician collected urethral , vaginal , and endocervical swabs for culture and nucleic acid amplification tests , polymerase chain reaction and ligase chain reaction . A positive culture , 2 positive nucleic acid amplification tests , or 1 positive nucleic acid amplification test confirmed by a separate nested polymerase chain reaction comprised the criterion st and ard to define a C. trachomatis-infected woman . RESULTS The prevalence of C. trachomatis was 22 % ( 30/139 women ) . All 9 test results were available for 126 participants ( 91 % ) .  Sensitivities were comparable for polymerase chain reaction and ligase chain reaction ( 52%-63 % ) , except for urine polymerase chain reaction ( 44 % ) , and were lower for culture ( 22%-37 % ) ; specificities were 99 % to 100 % , except for urine ligase chain reaction ( 91 % ) . Positive predictive values were > 93 % , except for urine ligase chain reaction ( 65 % ) ; negative predictive values were 83 % to 91 % . Combining nucleic acid amplification test results from 2 different specimens improved sensitivities without compromising specificity . CONCLUSION When C. trachomatis infection was defined by multiple tests from different specimen sources , the sensitivity of any 1 test from a single specimen source was lower than generally reported . The limitations of the use of a single test to identify C. trachomatis infection should be considered when test type , specimen source , and collection method for screening young women is being determined CONTEXT Chlamydia trachomatis infection is a serious public health concern that disproportionately affects adolescent girls . Although annual C trachomatis screening of sexually active adolescent girls is recommended by health professional organizations and is a Health Employer Data and Information Set ( HEDIS ) performance measure , this goal is not being met . OBJECTIVE To test the effectiveness of a system-level , clinical practice improvement intervention design ed to increase C trachomatis screening by using urine-based tests for sexually active adolescent girls identified during their routine checkups at a pediatric clinic . DESIGN , SETTING , AND PARTICIPANTS A r and omized cluster of 10 pediatric clinics in the Kaiser Permanente of Northern California health maintenance organization , where adolescent girls aged 14 to 18 years had a total of 7920 routine checkup visits from April 2000 through March 2002 . INTERVENTION Five clinics were r and omly assigned to provide usual care and 5 to provide the intervention , which required that leadership be engaged by showing the gap between best practice and current practice ; a team be assembled to champion the project ; barriers be identified and solutions developed through monthly meetings ; and progress be monitored with site-specific screening proportions . MAIN OUTCOME MEASURE Chlamydia trachomatis screening rate for sexually active 14- to 18-year-old girls during routine checkups at each participating clinic . RESULTS The population of adolescents was ethnically diverse with an average age of 15.4 years . Twenty-four percent of girls in the experimental clinics and 23 % in the control clinics were sexually active . Of the 1017 patients eligible for screening in the intervention clinic , 478 ( 47 % ) were screened ; of 1194 eligible for screening in the control clinic , 203 ( 17 % ) were screened . At baseline , the proportion screened was 0.05 ( 95 % confidence interval [ CI ] , 0.00 - 0.17 ) in the intervention and 0.14 ( 95 % CI , 0.01 - 0.26 ) in the control clinics . By months 16 to 18 , screening rates were 0.65 ( 95 % CI , 0.53 - 0.77 ) in the intervention and 0.21 ( 95 % CI , 0.09 - 0.33 ) in the control clinics ( time period by study group interaction , F(6,60 ) = 5.33 ; P<.001 ) . The average infection rate for the experimental clinics was 5.8 % ( 23 positive test results out of 393 total urine tests and a total of 3986 clinic visits ) vs 7.6 % in controls ( 12 positive test results out of 157 tests and 3934 clinic visits ) . CONCLUSIONS Implementation of this clinical practice intervention in a large health maintenance organization system is feasible , and it significantly increased the C trachomatis screening rates for sexually active adolescent girls during routine checkups We compared the efficacy of a screening program for urogenital Chlamydia trachomatis infections based on home sampling with that of a screening program based on conventional swab sampling performed at a physician 's office . Female subjects , comprising students at 17 high schools in the county of Aarhus , Denmark , were divided into a study group ( tested by home sampling ) and a control group ( tested in a physician 's office ) . We assessed the number of new infections and the number of subjects who reported being treated for pelvic inflammatory disease ( PID ) at 1 year of follow-up ; 443 ( 51.1 % ) of 867 women in the intervention group and 487 ( 58.5 % ) of 833 women in the control group were available for follow-up . Thirteen ( 2.9 % ) and 32 ( 6.6 % ) new infections were identified in the intervention group and the control group , respectively ( Wilcoxon exact value , P=.026 ) . Nine ( 2.1 % ) women in the intervention group and 20 ( 4.2 % ) in the control group reported being treated for PID ( P=.045 ) , indicating that a screening strategy involving home sampling is associated with a lower prevalence of C. trachomatis and a lower proportion of reported cases of PID OBJECTIVE To evaluate the value of a urine sample for diagnosing Chlamydia trachomatis infection in an STD clinic in a prospect i ve study of sample s collected from 410 consecutive STD patients ( 167 female and 243 male ) . METHODS Urine sample s were tested by enzyme immunoassay ( EIA ) and polymerase chain reaction ( PCR ) in comparison with cervical and /or urethral swabs tested by PCR and cell culture . A question naire was completed for a total of 320 patients concerning symptoms , and determining whether they were controls , contacts or were being tested subsequent to legal abortion . RESULTS The overall prevalence of C. trachomatis infection was 11.5 % . At least 40 % of patients were asymptomatic . Of the C. trachomatis-positive patients , 85 % were diagnosed by testing urine , compared to 91 % by testing swabs . For urine tests , the sensitivities of PCR were 66.7 % and 71.9 % for female and male patients , respectively , and the sensitivities of EIA were 40.0 % and 62.5 % , or 46.7 % and 71.9 % , for female and male patients , respectively , by including a 30 % gray zone below the cut-off value . For swabs , the sensitivities of PCR were 93.3 % and 87.5 % for female and male patients , respectively , and equal to the sensitivities of culture . In total , 3.3 % of controls and 35 % of contacts were found to be C. trachomatis positive . CONCLUSION The use of urine sample s for the diagnosis of C. trachomatis infections was effective , but urine sample s should be additional to conventional swab(s ) instead of replacing . Partner notification and a confirmation of cure is recommended Objectives : To determine the acceptability , to young men and women , of home screening for chlamydial infection . Methods : We wrote to a r and om sample of 208 women aged 18–25 years and 225 men aged 18–35 years from three general practice s , inviting them to undergo home screening for chlamydial infection . They were asked to return , by normal post , a urine specimen ( for men and half of the women ) or a vulval swab ( other half of the women ) for ligase chain reaction ( LCR ) testing for chlamydial infection . They were also asked to return a short question naire about risk status and the acceptability of this approach . Results : The participation rate among the available sample was 39 % for women and 46 % for men ( p=0.3 ) . However , among women , the rate was slightly higher ( p=0.05 ) for urine sample s ( 47 % ) than for vulval swabs ( 32 % ) . Six per cent of women and 9 % of men declined to take part , while 42 % of women and 33 % of men failed to respond . Two men objected to receiving the package at home . We received few other comments , positive and negative in about equal measure . Conclusion : Home screening for chlamydial infection is a potentially efficient method of reaching young people who may have little contact with health services . Men were at least as likely as women to respond to this screening approach . Home screening might form a useful component of a future chlamydial screening programme in the United Kingdom Nucleic acid amplification ( NAA ) methods for the diagnosis of genital Chlamydia trachomatis infection perform well but are technically dem and ing . Str and displacement amplification ( SDA ) assay is a new NAA method that offers technical simplicity but its comparative diagnostic performance is unknown . Here , we compare the diagnostic performance of ligase chain reaction with that of SDA in first-catch urine ( FCU ) sample s from both male and female patients and in endocervical swab ( ECS ) specimens . Attendees ( 715 men , 291 women ) of a city-centre genitourinary medicine clinic were studied . FCU specimens were collected from all the men and from 205 of the women in the study . Two ECS specimens were collected from each of the women . Discordant results were resolved using an in-house nested polymerase chain reaction technique . Sample s positive in two out of the three assays were considered positive . Prevalence of C. trachomatis infection was 9.2 % and 9.1 % in the men and women , respectively . Sensitivity , specificity , positive predictive value and negative predictive value of SDA  in FCU specimens from the men were 95.5 % , 100 % , 100 % and 99.5 % , respectively . In the female group , the figures for FCU and ECS specimens were 77.3 % , 100 % , 100 % and 97.3 % , and 90.9 % , 100 % , 100 % and 97.3 % , respectively . In this high-prevalence population , SDA assay is an effective method for the detection of C. trachomatis in FCU specimens in men and in ECS ( but not FCU ) specimens in women . Further studies in lower-prevalence population s are required 
    Output:
    
Implication s Nucleic acid amplification tests are easily obtainable non-invasive tests on urine sample s that detect chlamydia and gonorrhea reasonably well .
However , negative results on PCR assays on urine sample s are not useful to rule out gonococcal infections in women .
This method is a particularly robust way of synthesizing diagnostic test information across studies because it is relatively insensitive to the particular test threshold