***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: OBJECTIVE To compare first-voided urine specimens with paired  endocervical swab specimens from women to determine the role of urine in complementing or replacing swab specimens for the detection of the chlamydial antigen . DESIGN For 18 months , both endocervical swab specimens ( the criterion st and ard ) and urine specimens were tested for the chlamydial antigen , using an enzyme-linked immunosorbent assay ( Chlamydiazyme , Abbott Laboratories , North Chicago , Ill ) . Positive results were confirmed using a blocking reagent ( Abbott Laboratories ) and /or a direct fluorescent antibody test ( Micro-Trak , Syva , Palo Alto , Calif ) . A low level of chlamydial antigen ( below the enzyme-linked immunosorbent assay threshold recommended by the manufacturer ) was also looked for and , when found , was confirmed by the direct fluorescent antibody test . SETTING Prenatal and family practice clinics in a 500-bed community hospital . PATIENTS Specimens were collected from 489 r and om asymptomatic or symptomatic women . MAIN OUTCOME MEASURE The detection of the chlamydial antigen from  endocervical swab specimens  was compared with the detection from first-voided urine specimens . RESULTS Acceptable swab and urine specimens were obtained from 300 ( 61.3 % ) of the patients . The antigen of Chlamydia trachomatis was confirmed in 20 ( 6.7 % ) of the 300 women . Of the infected patients , the antigen was detected in both swab and urine specimens for nine patients ( 45 % ) , only in the swab specimens for eight ( 40 % ) , and only in the urine specimens for three ( 15 % ) . Testing urine in addition to endocervical swab specimens allowed for the detection of 18 % more chlamydial infections , whereas confirming the presence of the antigen below the enzyme-linked immunosorbent assay cutoff result ed in the detection of 54 % more infections . CONCLUSIONS Collecting multiple specimens and testing for low levels of chlamydial antigen may significantly improve the detection of chlamydial infections in women . First-voided urine may be an appropriate complementary specimen to endocervical swab specimens , but urine by itself does not allow for the adequate detection of the chlamydial antigen in women In a prospect i ve study , the Gen-Probe PACE 2 ( GP ) assay was compared with Abbott Laboratories ' ligase chain reaction ( LCR ) assay for the detection of Chlamydia trachomatis . A total of 493 female patients consented to collection of two cervical sample s ; a first-void urine ( FVU ) sample was collected also from 446 of the participants . Cervical sample s were tested by both GP and LCR ; 16 sample s ( 3.1 % ) tested positive by both methods and no discrepant results were observed . All but one of the FVU sample s collected from patients with a positive cervical sample was positive for C. trachomatis by LCR . The stability of FVU sample s over time in the LCR test was also evaluated and proved to be significantly longer than the 4 days stated by the manufacturer . While LCR proved to be highly sensitive in detecting chlamydial infection in FVU sample s , no difference was noted between LCR and GP in the detection of cervical C. trachomatis infection in this study population OBJECTIVE To evaluate the clinical utility of various diagnostic tests , two enzyme immunoassays and a chemiluminescent DNA probe were compared with cell culture ( with monoclonal antibody confirmation ) for the diagnosis of endocervical Chlamydia trachomatis infection . DESIGN The clinical performance of four diagnostic methods for Chlamydia trachomatis urogenital infections were compared , using specimens generated from consecutive pelvic examinations . SETTING Subjects were recruited from an urban adolescent clinic that provides primary and referral care . PARTICIPANTS A total of 479 adolescent female subjects were enrolled . The order of sample collection was r and omized . Subjects were stratified according to whether they were asymptomatic ( n = 228 ) or symptomatic ( n = 251 ) . MEASUREMENTS AND RESULTS Discrepant analysis was performed when culture was negative and nonculture technique was positive . The subject was considered to have chlamydia if culture was positive , or if one or more nonculture techniques , with that test 's confirmatory assay , were positive ( consensus-positive ) . Prevalence of chlamydia was 11.0 % in the asymptomatic , and 20.7 % in the symptomatic , group . Overall , 32.5 % of the infected subjects were asymptomatic . Sensitivity of diagnostic methods varied from 52 % to 80 % in the asymptomatic subjects , compared with 65 % to 81 % in symptomatic subjects . Culture sensitivity was 75 % to 80 % . The specificities of all tests were 96 % or greater . Accuracy of nonculture methods varied from 89.5 % ( DNA probe , symptomatic subjects ) to 96.9 % ( enzyme immunoassay asymptomatic subjects ) . CONCLUSIONS There are significant differences in symptomatic subjects when evaluating accuracy of test outcome , using a consensus-positive criterion . Asymptomatic infections account for nearly one third of adolescent females infected with chlamydia . The prevalence of chlamydia urogenital infections are underestimated by any single diagnostic test , particularly in the asymptomatic patient A new PCR kit ( AMPLICOR CT/NG ; Roche Diagnostic Systems , Inc. , Branchburg , N.J. ) was used as a screening tool for the detection of Chlamydia trachomatis and Neisseria gonorrhoeae in first-void urine ( FVU ) specimens from 3,340 asymptomatic women attending European health care units for contraceptive advice or pregnancy termination . All sample s were kept frozen ( -20 degrees C ) prior to testing . Chlamydia-positive sample s were retested once by the plasmid-based PCR kit and also by a major outer membrane protein ( MOMP ) primer-based PCR . Discrepancies were resolved by using the direct immunofluorescence test ( DIF ) with the centrifuged sediment of the FVU specimens . Sample s positive for N. gonorrhoeae were retested by chromosomal primer-based PCR and verified by a 16S RNA PCR . Of the sample s tested , 1.8 % were considered inhibitory by using the internal amplification control . Of 81 sample s positive for C. trachomatis , 74 sample s were positive by both plasmid- and MOMP-based PCRs , 6 sample s were positive by plasmid-based PCR and DIF , and one sample was positive by both MOMP-based PCR and DIF . Nine sample s ( 0.3 % ) were positive for N. gonorrhoeae by the chromosomal primer-based PCR ; however , none of the results could be confirmed . The test offers the unique ability to identify inhibition of amplification with the optional internal control Traditionally , evaluations of nonculture assays for Chlamydia trachomatis are based on a comparison with urethral culture in men and cervical culture in women as the st and ard for positivity of infection , but it is known that culture may be less than 100 % sensitive . A chemiluminometric immunoassay , Magic Lite ( Ciba Corning , Medfield , MA ) that detects C. trachomatis antigens was performed on centrifuged first void urine sample s and urethral swabs collected from men attending a sexually transmitted disease ( STD ) clinic . Immunoassay performance was compared to urethral culture and also to a broader gold st and ard : an infected patient with positive culture results or a confirmed positive Chlamydiazyme enzyme immunoassay ( Abbott , Chicago ) result . Two studies were performed on a retrospective group of stored first void urine sample s from 200 men and a prospect i ve group of urethral swabs and first void urine sample s from 199 men . Exp and ing the gold st and ard showed that a urethral swab assayed by culture had a sensitivity between 70.3 % and 87.5 % , with the following effects on immunoassay performance in the prospect i ve study : the sensitivity of urethral swabbing was reduced from 96.2 % to 78.4 % ( specificity increased from 96.0 % to 98.1 % ) and first void urine sensitivity increased from 92.3 % to 94.6 % ( specificity went from 87.9 % to 93.8 % ) . In the retrospective study , sensitivity of first void urine testing went from 91.4 % to 92.5 % , with a corresponding increase in specificity from 93.9 % to 96.9 % . This maneuver had relatively little impact on the negative predictive values , but dramatically increased the positive predictive values , for both sample s. ( ABSTRACT TRUNCATED AT 250 WORDS Urogenital infections with Chlamydia trachomatis are widespread and usually asymptomatic . Major complications from infection include ectopic pregnancies and female infertility.1 Although contact tracing reduces the prevalence of chlamydia infection,2 the test rate among partners is often low , partly because male contacts have to have a urethral swab taken by a doctor . As the polymerase chain reaction can successfully detect infection in urine sample s,3 we investigated whether the test rate could be increased by asking the male contacts of infected women to send a urine sample directly from home to a laboratory instead of having a doctor take a urethral swab .  Ninety six women with C trachomati s infection seen in general practice s in Aarhus County , Denmark , were r and omly divided according to their date of birth into an intervention group ( 45 patients ) and a Ninety-seven asymptomatic 16 - 21-year-old sexually active adolescent males were evaluated for gonorrhea and chlamydia by culture ,  chlamydia enzyme immunoassay , and an analysis of a r and om urine sample for pyuria using centrifuged urine and urine cytometer . The incidence of gonorrhea was 5.3 % and chlamydia by culture 12.3 % . Immunoassay was superior in sensitivity and specificity ( 75 % and 99 % , respectively ) to centrifuged urine ( sensitivity 58 % , specificity 92 % ) or urine cytometer ( 58 % and 91 % ) in identifying asymptomatic chlamydia urethritis . Chlamydia enzyme immunoassay is an acceptable , more rapid , and less expensive alternative to culture . The absence of pyuria in asymptomatic males can not be assumed to indicate the absence of a sexually transmitted disease Background and Objectives : Previous studies have shown that self‐inserted vaginal tampons can be used to obtain specimens for detection of Neisseria gonorrhoeae . There is a need to exp and testing for infection with Chlamydia trachomatis to women who do not undergo regular gynecologic examinations . Goal : To compare self‐inserted tampons with clinician‐obtained endocervical swabs for collection of sample s to be examined for chlamydial infection . Study Design : Women referred because of recently detected untreated chlamydial infection inserted a vaginal tampon . Two endocervical swabs were obtained after the tampon was removed . One swab was cultured for Chlamydia trachomatis . The other swab and the tampon were examined with the Testpack Chlamydia antigen detection test . Results : Sixty‐nine women were studied .  Chlamydial infection was detected by culture in 75.4 % , by Testpack ( swab ) in 63.8 % , and by Testpack ( tampon ) in 52.2 % . Conclusions : Tampon‐obtained specimens evaluated in the Testpack Chlamydia test were relatively insensitive . More sensitive tests for the detection of Chlamydia trachomatis infection with self‐obtained specimens should be evaluated AIMS : To increase the sensitivity of an automated chlamydia enzyme immunoassay by significantly lowering its cut off value , and to maintain specificity by confirmation with polymerase chain reaction ( PCR ) and direct immunofluorescent antibody test ( DFA ) . METHODS : Over five months , the cut off value of the enzyme immunoassay used to screen urogenital sample s for chlamydia antigen was reduced from 80 to 10 . Sample s with a test value of 10 or above were further tested with a commercial PCR assay . All sample s during the first three months and discrepant sample s during the last two months of the study were also tested with the DFA . RESULTS : 3250 urogenital swabs ( 1246 urethral , 1335 endocervical , 669 pooled urethral/endocervical ) from 1246 males and 2004 females were processed . Using the manufacturer 's recommended cut off of 80 , the enzyme immunoassay identified chlamydia antigen in 134 sample s ( 4.1 % ) . Using the lower cut off value of 10 and either PCR or DFA as the confirmatory test , Chlamydia trachomatis was identified in 178 sample s ( 5.5 % ) . Thus , 45 additional positive sample s were identified and the confirmed detection rate was increased by 33.8 % ( 45/133 ) . Excluding equivocal PCR results , the concordance between D 
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The results showed that while specificities were high , sensitivities varied widely across the tests and were also dependent on the specimen tested .
Meta- analysis demonstrated that DNA amplification techniques performed best for both urine and swabs in low prevalence population s. We conclude that nucleic acid amplification tests used on non-invasive sample s 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