The Experts below are selected from a list of 2184 Experts worldwide ranked by ideXlab platform
Edward W. Hook - One of the best experts on this subject based on the ideXlab platform.
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Opportunistic urine Ligase Chain Reaction screening for sexually transmitted diseases in adolescents seeking care in an urban emergency department
Annals of emergency medicine, 2000Co-Authors: Michelle Embling, Kathy Monroe, Edward W. HookAbstract:Abstract Study Objective: Neisseria gonorrhoeae and Chlamydia trachomatis are the most common bacterial sexually transmitted diseases (STDs) in sexually active youth and many infections are asymptomatic or unrecognized. This study used Ligase Chain Reaction assays for determination of prevalence of gonococcal and chlamydial infections in adolescents seeking care at an urban emergency department. Methods: An unlinked prevalence study was performed with Ligase Chain Reaction tests on voided urine specimens from a convenience sample of adolescents 14 years or older who sought care at the Children's Hospital of Alabama ED. Demographic data and data on care provided in the ED were determined from retrospective chart review of those patients whose urine specimens were tested. Results: Of 282 urine specimens screened, 13.5% (38) yielded positive findings on Ligase Chain Reaction testing for either or both pathogens (20 [7%] positive for N gonorrhoeae, 23 [8%] positive for C trachomatis). In the context of acute care, gonorrhea or chlamydial infection was diagnosed in 5 (1.8%). STD prevalence did not vary significantly by age. Only 39% (15/38) of patients with infections detected by Ligase Chain Reaction testing received potentially effective antibiotics as a result of their urgent care evaluation. Conclusion: Many adolescents use the ED for nonurgent care and unsuspected STDs are often missed. Urine Ligase Chain Reaction testing is a sensitive, noninvasive means of detecting STDs by which unsuspected adolescent STD cases can be detected in an ED setting. [Embling ML, Monroe KW, Oh MK, Hook EW III. Opportunistic urine Ligase Chain Reaction screening for sexually transmitted diseases in adolescents seeking care in an urban emergency department. Ann Emerg Med. July 2000;36:28-32.]
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Opportunistic Urine Ligase Chain Reaction Screening for STDs in Adolescents Attending an Urban Emergency Department
Pediatric Research, 1999Co-Authors: Kathy Monroe, Michelle Embling, Edward W. Hook, Charity M. RicheyAbstract:Opportunistic Urine Ligase Chain Reaction Screening for STDs in Adolescents Attending an Urban Emergency Department
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Detection of Chlamydia trachomatis endocervical infections by Ligase Chain Reaction versus ACCESS Chlamydia antigen assay.
Journal of clinical microbiology, 1999Co-Authors: Ken B. Waites, Kim Smith, M. A. Crum, R. D. Hockett, A. H. Wells, Edward W. HookAbstract:Ligase Chain Reaction (LCR) was compared with ACCESS immunoassay for detection of chlamydial infections in females. Despite efforts to improve ACCESS performance by evaluation of specimens that were in the test performance "grey zone," LCR remained more sensitive and was less expensive to perform. ACCESS had a sensitivity of 83.9%, a specificity of 99.7%, a positive predictive value of 96.3%, and a negative predictive value of 98.5%.
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Diagnosis of genitourinary Chlamydia trachomatis infections by using the Ligase Chain Reaction on patient-obtained vaginal swabs.
Journal of clinical microbiology, 1997Co-Authors: Edward W. Hook, Kim Smith, Carolyn Mullen, Joan Stephens, Laurie Rinehardt, Mitchell S. Pate, Helen H. LeeAbstract:We compared the Ligase Chain Reaction (LCR) assay to cell culture for diagnosis of genitourinary chlamydial infections in women using swab specimens obtained by clinicians from the endocervix and by patients from their own vaginas. Specimens from 40 (12.9%) of 309 patients were positive for chlamydial infection by culture, while the specimens of 50 (16.2%) patients were positive by LCR. Chlamydia trachomatis infection was verified for 9 of 10 patients whose LCR specimens were positive but whose cultures were negative. Vaginal and cervical swab specimens were positive by LCR for 46 (93.9%) and 44 (89.8%) of 49 chlamydia-infected patients, respectively. These data suggest that LCR testing for chlamydia with vaginal swab specimens obtained by patients themselves is as sensitive as cervical LCR and more sensitive than cell culture.
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Ligase Chain Reaction for detection of Neisseria gonorrhoeae in urogenital swabs.
Journal of clinical microbiology, 1995Co-Authors: S Ching, H Lee, Edward W. Hook, M R Jacobs, J ZenilmanAbstract:The Ligase Chain Reaction (LCR) is an in vitro nucleic acid amplification technique that exponentially amplifies targeted DNA sequences. In a multicenter study, we evaluated the use of a 4-h LCR-based assay for the diagnosis of Neisseria gonorrhoeae infection of the cervix and male urethra. The LCR results were compared with those of culture for N. gonorrhoeae by using selective media. This assay amplifies target sequences within the N. gonorrhoeae opacity gene. Discordant LCR-positive and culture-negative specimens were further evaluated by testing by another LCR assay which used N. gonorrhoeae-specific pilin probe sets. A total of 1,539 female endocervical specimens and 808 male urethral swab specimens were evaluated in the study. An expanded "gold standard" was defined to include all culture-positive as well as culture-negative, confirmed LCR-positive specimens. After resolution of discrepant samples, the sensitivities of the N. gonorrhoeae LCR assays for the female and male specimens were 97.3 and 98.5%, respectively, with specificities of 99.6 and 99.8%, respectively. Resolved culture sensitivities were 83.9 and 96.5% for the female and male specimens, respectively. The LCR assay for gonorrhea is a rapid, highly sensitive nonculture method for detecting gonococcal infection of the cervix and male urethra.
Helen H. Lee - One of the best experts on this subject based on the ideXlab platform.
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detection of genitourinary tract chlamydia trachomatis infection in pregnant women by Ligase Chain Reaction assay
Obstetrics & Gynecology, 1997Co-Authors: William W. Andrews, Helen H. Lee, William J. Roden, Cynthia W MottAbstract:Objective To compare the sensitivity and specificity of a Ligase Chain Reaction assay of cervical swabs and voided urine with those of cervical swab tissue culture for the detection of genitourinary tract infection with Chlamydia trachomatis in pregnant women. Methods Infection with C trachomatis was assessed in cervical swabs by culture and in both cervical swabs and voided urine specimens by a Ligase Chain Reaction assay specific for C trachomatis plasmid DNA. The matched cervical swab and voided urine specimens were collected from 462 women during routine visits to prenatal clinics. Standard criteria that defined infection included: 1) a positive cervical culture result or 2) a negative culture but a positive Ligase Chain Reaction result in either the urine or cervical specimen that was confirmed by supplementary testing. Test performance was assessed by determination of sensitivity and specificity, and differences in paired results were determined using McNemar analysis. Results The prevalence of genitourinary C trachomatis infection was 6.1% (n = 28) by cervical culture (sensitivity 30.1%; specificity 100%), 18.2% (n = 84) by Ligase Chain Reaction of cervical swabs (sensitivity 90.3%; specificity 100%), and 16.9% (n = 78) by Ligase Chain Reaction of urine (sensitivity 83.9%; specificity 99.5%). Relative to the number of women with a positive culture or a confirmed Ligase Chain Reaction-positive cervical swab, the sensitivity and specificity were 82.8% and 97.9%, respectively, for Ligase Chain Reaction of urine and 96.6% and 100%, respectively, for Ligase Chain Reaction of cervical swabs. Ligase Chain Reaction of cervical swabs and urine detected 89.3% and 82.1%, respectively, of women with a positive cervical culture. Conclusions Ligase Chain Reaction assay of cervical or urine specimens detected considerably more pregnant women with C trachomatis infection of the genitourinary tract than did cervical culture. Ligase Chain Reaction testing of urine is a simple and effective means of screening pregnant women for genitourinary tract infection with C trachomatis.
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Detection of genitourinary tract Chlamydia trachomatis infection in pregnant women by Ligase Chain Reaction assay.
Obstetrics and gynecology, 1997Co-Authors: William W. Andrews, Helen H. Lee, William J. Roden, Cynthia W MottAbstract:To compare the sensitivity and specificity of a Ligase Chain Reaction assay of cervical swabs and voided urine with those of cervical swab tissue culture for the detection of genitourinary tract infection with Chlamydia trachomatis in pregnant women. Infection with C trachomatis was assessed in cervical swabs by culture and in both cervical swabs and voided urine specimens by a Ligase Chain Reaction assay specific for C trachomatis plasmid DNA. The matched cervical swab and voided urine specimens were collected from 462 women during routine visits to prenatal clinics. Standard criteria that defined infection included: 1) a positive cervical culture result or 2) a negative culture but a positive Ligase Chain Reaction result in either the urine or cervical specimen that was confirmed by supplementary testing. Test performance was assessed by determination of sensitivity and specificity, and differences in paired results were determined using McNemar analysis. The prevalence of genitourinary C trachomatis infection was 6.1% (n = 28) by cervical culture (sensitivity 30.1%; specificity 100%), 18.2% (n = 84) by Ligase Chain Reaction of cervical swabs (sensitivity 90.3%; specificity 100%), and 16.9% (n = 78) by Ligase Chain Reaction of urine (sensitivity 83.9%; specificity 99.5%). Relative to the number of women with a positive culture or a confirmed Ligase Chain Reaction-positive cervical swab, the sensitivity and specificity were 82.8% and 97.9%, respectively, for Ligase Chain Reaction of urine and 96.6% and 100%, respectively, for Ligase Chain Reaction of cervical swabs. Ligase Chain Reaction of cervical swabs and urine detected 89.3% and 82.1%, respectively, of women with a positive cervical culture. Ligase Chain Reaction assay of cervical or urine specimens detected considerably more pregnant women with C trachomatis infection of the genitourinary tract than did cervical culture. Ligase Chain Reaction testing of urine is a simple and effective means of screening pregnant women for genitourinary tract infection with C trachomatis.
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Diagnosis of genitourinary Chlamydia trachomatis infections by using the Ligase Chain Reaction on patient-obtained vaginal swabs.
Journal of clinical microbiology, 1997Co-Authors: Edward W. Hook, Kim Smith, Carolyn Mullen, Joan Stephens, Laurie Rinehardt, Mitchell S. Pate, Helen H. LeeAbstract:We compared the Ligase Chain Reaction (LCR) assay to cell culture for diagnosis of genitourinary chlamydial infections in women using swab specimens obtained by clinicians from the endocervix and by patients from their own vaginas. Specimens from 40 (12.9%) of 309 patients were positive for chlamydial infection by culture, while the specimens of 50 (16.2%) patients were positive by LCR. Chlamydia trachomatis infection was verified for 9 of 10 patients whose LCR specimens were positive but whose cultures were negative. Vaginal and cervical swab specimens were positive by LCR for 46 (93.9%) and 44 (89.8%) of 49 chlamydia-infected patients, respectively. These data suggest that LCR testing for chlamydia with vaginal swab specimens obtained by patients themselves is as sensitive as cervical LCR and more sensitive than cell culture.
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Noninvasive Tests for Diagnosis of Chlamydia trachomatis Infection: Application of Ligase Chain Reaction to First-Catch Urine Specimens of Women
The Journal of infectious diseases, 1995Co-Authors: Julius Schachter, John D. Burczak, Jeanne Moncada, Robin Whidden, Howard Shaw, Gail Bolan, Helen H. LeeAbstract: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.
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Diagnosis of Chlamydia trachomatis genitourinary infection in women by Ligase Chain Reaction assay of urine
Lancet (London England), 1995Co-Authors: Helen H. Lee, S Muldoon, William W. Andrews, Max Chernesky, Julius Schachter, J D Burczak, G Leckie, Walter E. StammAbstract:Abstract Genitourinary infection with Chlamydia trachomatis is a common and potentially serious sexually transmitted disease. Diagnosis of C trachomatis infection in women typically relies on culture of endocervical swabs, an invasive and expensive procedure. The Ligase Chain Reaction (LCR) is an in-vitro nucleic acid amplification technique that exponentially amplifies selected DNA sequences. We have compared an LCR-based assay to detect C trachomatis plasmid DNA in first void urine with culture of endocervical swabs for matched specimens from 1937 women from four geographic regions. Discordant specimen pairs were further tested by direct fluorescent antibody staining for elementary bodies and an alternative LCR assay based on the chlamydial outer membrane protein gene. An "expanded gold standard" was defined to include all culture-positive as well as culture-negative, confirmed LCR-positive women. The sensitivity and specificity of the LCR assay with first void urine samples compared with the expanded gold standard were 93·8% and 99·9%, respectively; the corresponding values for culture were 65·0% and 100%, respectively. Thus, an automated LCR assay of readily obtained urine samples showed a detection rate for infected women almost 30% greater than that of endocervical swab culture. The LCR assay was highly effective for the detection of C trachomatis in urine from women with or without signs or symptoms of chlamydial genitourinary tract infection.
Peter Wilding - One of the best experts on this subject based on the ideXlab platform.
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Mutation detection using Ligase Chain Reaction in passivated silicon-glass microchips and microchip capillary electrophoresis.
BioTechniques, 2004Co-Authors: Xing Jian Lou, Nicholas J Panaro, Peter Wilding, Paolo Fortina, Larry J. KrickaAbstract:The Ligase Chain Reaction (LCR) following PCR is one of the most sensitive and specific methods for detecting mutations, especially single nucleotide polymorphisms (SNPs). Performing LCR in microchips remains a challenge because of the inhibitory effect of the internal surfaces of silicon-glass microchips. We have tested a dynamic polymer-based surface passivation method for LCR conducted in oxide-coated silicon-glass microchips. The combination of polyvinylpyrrolidone 40 (PVP-40) at 0.75% (w/v) with an excess of the Ligase produced successful LCR in the silicon-glass microchips, with yields of ligated primers comparable to Reactions performed in conventional Reaction tubes. Ligated primers were detected and quantified simply and conveniently using microchip capillary electrophoresis.
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Analysis of Ligase Chain Reaction products amplified in a silicon-glass chip using capillary electrophoresis
Journal of chromatography. A, 1996Co-Authors: Jing Cheng, Larry J. Kricka, Mann A. Shoffner, Keith R. Mitchelson, Peter WildingAbstract:Ligase Chain Reaction (LCR) is a useful molecular technique for detecting known point mutations. We report the first example of the use of a disposable silicon-glass micro-chip for LCR and the first application of capillary electrophoresis (CE) to analyze samples amplified by LCR in a chip. Silicon-glass chips were manufactured using conventional photolithography and anodic bonding. The chips provide three distinct advantages for LCR: excellent thermal conductivity, a micro Reaction volume ( < 10 microliters), and reproducible, low-cost manufacturing. Investigation and quantitation of amplification efficiency of LCR in a chip or in a tube requires an analytical technique that is faster and more convenient than the conventional slab gel methods. Slab gel electrophoresis uses relatively large amounts of sample and is labor-intensive and time-consuming, and thus is unsuitable for the separation and detection of LCR products. In contrast CE requires sample volume (original LCR products) of less than 1 microliter and is therefore well-suited to analysis of the micro-volume Reaction mixture from chips. We combined CE with a sensitive laser induced fluorescence (LIF) detection system for the rapid separation and quantitative detection of LCR products amplified from the lacI gene in a silicon-glass chip. Comparative studies were made with LCR between tubes and silicon-glass chips. CE-LIF analysis is ideally suited to examination of micro-LCR amplification with high throughput. The technologies may find medical uses in disease diagnosis and research.
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analysis of Ligase Chain Reaction products amplified in a silicon glass chip using capillary electrophoresis
Journal of Chromatography A, 1996Co-Authors: Jing Cheng, Larry J. Kricka, Mann A. Shoffner, Keith R. Mitchelson, Peter WildingAbstract:Abstract Ligase Chain Reaction (LCR) is a useful molecular technique for detecting known point mutations. We report the first example of the use of a disposable silicon-glass micro-chip for LCR and thefirst application capillary electrophoresis (CE) to analyze samples amplified by LCR in a chip. Silicon-glass chips were manufactured using conventional photolithography and anodic bonding. The chips provide three distinct advantages for LCR: excellent thermal conductivity, a micro Reaction volume ( μ l), and reproducible,, low-cost manufacturing. Investigation and quantitation of amplification efficiency of LCR in a chip or in a tube requires an analytical technique that is faster and more convenient than the conventional slab gel methods. Slab gel electrophoresis uses relatively large amounts of sample and is labor-intensive and time-consuming, and thus is unsuitable for the separation and detection of LCR products. In contrast CE requires sample volumes (original LCR products) of less than 1 μl and is therefore well-suited to analysis of the micro-volume Reaction mixture from chips. We combined CE with a sensitive laser induced fluorescence (LIF) detection system for the rapid separation and quantitative detection of LCR products amplified from the lacI gene in a silicon-glass chip. Comparative studies were made with LCR between tubes and silicon-glass chips. CE-LIF analysis is ideally suited to examination of micro-LCR amplification with high thoughput. The technologies may find medical uses in disease diagnosis and research.
Larry J. Kricka - One of the best experts on this subject based on the ideXlab platform.
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Mutation detection using Ligase Chain Reaction in passivated silicon-glass microchips and microchip capillary electrophoresis.
BioTechniques, 2004Co-Authors: Xing Jian Lou, Nicholas J Panaro, Peter Wilding, Paolo Fortina, Larry J. KrickaAbstract:The Ligase Chain Reaction (LCR) following PCR is one of the most sensitive and specific methods for detecting mutations, especially single nucleotide polymorphisms (SNPs). Performing LCR in microchips remains a challenge because of the inhibitory effect of the internal surfaces of silicon-glass microchips. We have tested a dynamic polymer-based surface passivation method for LCR conducted in oxide-coated silicon-glass microchips. The combination of polyvinylpyrrolidone 40 (PVP-40) at 0.75% (w/v) with an excess of the Ligase produced successful LCR in the silicon-glass microchips, with yields of ligated primers comparable to Reactions performed in conventional Reaction tubes. Ligated primers were detected and quantified simply and conveniently using microchip capillary electrophoresis.
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Analysis of Ligase Chain Reaction products amplified in a silicon-glass chip using capillary electrophoresis
Journal of chromatography. A, 1996Co-Authors: Jing Cheng, Larry J. Kricka, Mann A. Shoffner, Keith R. Mitchelson, Peter WildingAbstract:Ligase Chain Reaction (LCR) is a useful molecular technique for detecting known point mutations. We report the first example of the use of a disposable silicon-glass micro-chip for LCR and the first application of capillary electrophoresis (CE) to analyze samples amplified by LCR in a chip. Silicon-glass chips were manufactured using conventional photolithography and anodic bonding. The chips provide three distinct advantages for LCR: excellent thermal conductivity, a micro Reaction volume ( < 10 microliters), and reproducible, low-cost manufacturing. Investigation and quantitation of amplification efficiency of LCR in a chip or in a tube requires an analytical technique that is faster and more convenient than the conventional slab gel methods. Slab gel electrophoresis uses relatively large amounts of sample and is labor-intensive and time-consuming, and thus is unsuitable for the separation and detection of LCR products. In contrast CE requires sample volume (original LCR products) of less than 1 microliter and is therefore well-suited to analysis of the micro-volume Reaction mixture from chips. We combined CE with a sensitive laser induced fluorescence (LIF) detection system for the rapid separation and quantitative detection of LCR products amplified from the lacI gene in a silicon-glass chip. Comparative studies were made with LCR between tubes and silicon-glass chips. CE-LIF analysis is ideally suited to examination of micro-LCR amplification with high throughput. The technologies may find medical uses in disease diagnosis and research.
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analysis of Ligase Chain Reaction products amplified in a silicon glass chip using capillary electrophoresis
Journal of Chromatography A, 1996Co-Authors: Jing Cheng, Larry J. Kricka, Mann A. Shoffner, Keith R. Mitchelson, Peter WildingAbstract:Abstract Ligase Chain Reaction (LCR) is a useful molecular technique for detecting known point mutations. We report the first example of the use of a disposable silicon-glass micro-chip for LCR and thefirst application capillary electrophoresis (CE) to analyze samples amplified by LCR in a chip. Silicon-glass chips were manufactured using conventional photolithography and anodic bonding. The chips provide three distinct advantages for LCR: excellent thermal conductivity, a micro Reaction volume ( μ l), and reproducible,, low-cost manufacturing. Investigation and quantitation of amplification efficiency of LCR in a chip or in a tube requires an analytical technique that is faster and more convenient than the conventional slab gel methods. Slab gel electrophoresis uses relatively large amounts of sample and is labor-intensive and time-consuming, and thus is unsuitable for the separation and detection of LCR products. In contrast CE requires sample volumes (original LCR products) of less than 1 μl and is therefore well-suited to analysis of the micro-volume Reaction mixture from chips. We combined CE with a sensitive laser induced fluorescence (LIF) detection system for the rapid separation and quantitative detection of LCR products amplified from the lacI gene in a silicon-glass chip. Comparative studies were made with LCR between tubes and silicon-glass chips. CE-LIF analysis is ideally suited to examination of micro-LCR amplification with high thoughput. The technologies may find medical uses in disease diagnosis and research.
Marius Domeika - One of the best experts on this subject based on the ideXlab platform.
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Cervical, urine and vaginal specimens for detection of Chlamydia trachomatis by Ligase Chain Reaction in women: a comparison.
Acta dermato-venereologica, 2001Co-Authors: Eva Hjelm, A Hallén, Marius DomeikaAbstract:Screening for Chlamydia trachomatis in women is generally done using only one specimen from each patient in order to minimize costs. In this study the aim was to compare the performances of vaginal, cervical and urinary specimens in a population of young women with sparse symptoms. During 1998, specimens from 1,001 women at the Departments of Venereology and Youth Health Care at the University Hospital of Uppsala, Sweden were examined by both Ligase Chain Reaction and cell culture for detection of C. trachomatis. The samples from the cervix, vagina and urine were tested by Ligase Chain Reaction, while specimens for cell culture were collected from the cervix and urethra. The prevalence of genital C. trachomatis infections was 5.1%. A single urine specimen had a sensitivity of 80.0%, while the sensitivity of a single vaginal specimen was 96.0%. The specificity was 100% for the urine specimens and 99.4% for the vaginal specimens. The sensitivity and specificity of a single cervical specimen was 92.0% and 99.6%, respectively. Although the urine Ligase Chain Reaction seemed to have the lowest sensitivity of the compared specimens for testing of C. trachomatis infections in this population, the differences in sensitivity between urine, cervical and vaginal specimens were not statistically significant.
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Cervical, urine and vaginal specimens for detection of Chlamydia trachomatis by Ligase Chain Reaction in women
2001Co-Authors: Eva Hjelm, Marius Domeika, A HallénAbstract:Cervical, urine and vaginal specimens for detection of Chlamydia trachomatis by Ligase Chain Reaction in women
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Detection of Chlamydia trachomatis in urine specimens from women by Ligase Chain Reaction
Journal of clinical microbiology, 1995Co-Authors: M Bassiri, Marius Domeika, J D Burczak, H H Lee, L O Svensson, P A MårdhAbstract:The performance of a plasmid-based Ligase Chain Reaction (LCR) with urine specimens was compared with those of cell culture of cervical swabs and enzyme immunoassay with urine specimens for the detection of Chlamydia trachomatis infection in women who had attended a family planning clinic. The prevalence of chlamydial infection determined by LCR was 3.1%. Discrepant results among the three assays were resolved by testing urine by a second LCR assay based on the C. trachomatis chromosomal gene encoding the major outer membrane protein. Sensitivity, specificity, and positive and negative predictive values for the cell cultures were 56.3, 100, 100, and 98.4%, respectively, whereas those for the enzyme immunoassay were 18.8, 100, 100, and 97.1%, respectively, and those for LCR were 87.5, 100, 100, and 99.5%, respectively. LCR thus provides a highly sensitive and specific noninvasive screening method for detecting genital chlamydial infections in women.