Analytical Evaluation of the Abbott RealTime CT/NG Assay for Detection of Chlamydia trachomatis and Neisseria gonorrhoeae in Rectal and Pharyngeal Swabs

Abstract

Chlamydia trachomatis and Neisseria gonorrhoeae infections in the rectum and pharynx are important extragenital reservoirs of infection. Few assays approved by the US Food and Drug Administration are commercially available to diagnose pharyngeal or rectal infections. The current study reports on the analytical performance of the Abbott RealTime CT/NG assay, including the limit of detection, inclusivity, and analytical specificity for C. trachomatis and N. gonorrhoeae in rectal and pharyngeal specimens. The limit of detection was performed using known concentrations of organisms, elementary bodies per milliliter (EB/mL) for C. trachomatis and colony-forming units per milliliter (CFU/mL) for N. gonorrhoeae, in clinical rectal and pharyngeal swab matrices. Inclusivity was performed against 12 serovars of C. trachomatis and seven strains of N. gonorrhoeae. The analytical specificity was performed using 28 different bacteria and viruses. The limit of detection for C. trachomatis was 2.56 EB/mL in pharyngeal specimens and 12.8 EB/mL in rectal specimens. The limit of detection for N. gonorrhoeae was 0.0256 CFU/mL for both pharyngeal and rectal specimens. The inclusivity and analytical specificity were 100% for both rectal and pharyngeal specimens. These analytical performance data demonstrate that the Abbott CT/NG RealTime assay is an accurate, sensitive, and specific assay in rectal and pharyngeal specimens, supporting the potential of the assay for detection of rectal and pharyngeal C. trachomatis and N. gonorrhoeae infections. Chlamydia trachomatis and Neisseria gonorrhoeae infections in the rectum and pharynx are important extragenital reservoirs of infection. Few assays approved by the US Food and Drug Administration are commercially available to diagnose pharyngeal or rectal infections. The current study reports on the analytical performance of the Abbott RealTime CT/NG assay, including the limit of detection, inclusivity, and analytical specificity for C. trachomatis and N. gonorrhoeae in rectal and pharyngeal specimens. The limit of detection was performed using known concentrations of organisms, elementary bodies per milliliter (EB/mL) for C. trachomatis and colony-forming units per milliliter (CFU/mL) for N. gonorrhoeae, in clinical rectal and pharyngeal swab matrices. Inclusivity was performed against 12 serovars of C. trachomatis and seven strains of N. gonorrhoeae. The analytical specificity was performed using 28 different bacteria and viruses. The limit of detection for C. trachomatis was 2.56 EB/mL in pharyngeal specimens and 12.8 EB/mL in rectal specimens. The limit of detection for N. gonorrhoeae was 0.0256 CFU/mL for both pharyngeal and rectal specimens. The inclusivity and analytical specificity were 100% for both rectal and pharyngeal specimens. These analytical performance data demonstrate that the Abbott CT/NG RealTime assay is an accurate, sensitive, and specific assay in rectal and pharyngeal specimens, supporting the potential of the assay for detection of rectal and pharyngeal C. trachomatis and N. gonorrhoeae infections. Chlamydia trachomatis and Neisseria gonorrhoeae are the two most commonly reported sexually transmitted infections in the United States, and the number of cases is increasing.1Workowski K.A. Bolan G.A. Sexually transmitted diseases treatment guidelines, 2015.MMWR Recomm Rep. 2015; 64: 1-137Crossref PubMed Scopus (27) Google Scholar,2Centers for Disease Control and PreventionSexually Transmitted Disease Surveillance 2017. US Department of Health and Human Services, Atlanta2018Google Scholar The rectum and pharynx are important extragenital reservoirs of infection because rectal infections are associated with increased risk of HIV acquisition,3Bernstein K.T. Marcus J.L. Nieri G. Philip S.S. Klausner J.D. Rectal gonorrhea and chlamydia reinfection is associated with increased risk of HIV seroconversion.J Acquir Immune Defic Syndr. 2010; 53: 537-543Crossref PubMed Scopus (252) Google Scholar and oropharyngeal infections are hypothesized to be a source of gonococcal antimicrobial resistance due to decreased tissue penetration of antimicrobial agents.4Unemo M. Shafer W.M. Antimicrobial resistance in Neisseria gonorrhoeae in the 21st century: past, evolution, and future.Clin Microbiol Rev. 2014; 27: 587-613Crossref PubMed Scopus (598) Google Scholar Rectal and pharyngeal infections are typically asymptomatic; thus, detection and treatment of infections at these sites rely on effective screening tests. The US Centers for Disease Control and Prevention (CDC) recommends screening of all sexually active men who have sex with men (MSM) for rectal C. trachomatis and N. gonorrhoeae infections and pharyngeal N. gonorrhoeae at least annually.1Workowski K.A. Bolan G.A. Sexually transmitted diseases treatment guidelines, 2015.MMWR Recomm Rep. 2015; 64: 1-137Crossref PubMed Scopus (27) Google Scholar Because of their high sensitivity and specificity, nucleic acid amplification tests have become the recommended method for detecting N. gonorrhoeae and C. trachomatis infections of the urogenital tract.5Centers for Disease Control and PreventionRecommendations for the laboratory-based detection of Chlamydia trachomatis and Neisseria gonorrhoeae--2014.MMWR Recomm Rep. 2014; 63: 1-19Google Scholar Until recently, no commercial nucleic acid amplification test was approved by the US Food and Drug Administration (FDA) for use on pharyngeal or rectal specimens. However, a recent clinical trial performed by the authors evaluated the performance of three commercially available assays for detection of C. trachomatis and N. gonorrhoeae in pharyngeal and rectal specimens (ClinicalTrials.gov Identifier: NCT02870101). The results of that study were used to support FDA clearance for the detection of C. trachomatis and N. gonorrhoeae in two of the three assays for rectal and pharyngeal swabs.6Food and Drug AdministrationFDA Clears First Diagnostic Tests for Extragenital Testing for Chlamydia and Gonorrhea. Food and Drug Administration, White Oak, MDMarch 23, 2019Google Scholar The Abbott RealTime CT/NG assay was included in the aforementioned study and used to create the anatomic site infected standard.7Doernberg S.B. Komarow L. Tran T.T.T. Sund Z. Pandori M.W. Jensen D. Tsalik E.L. Deal C.D. Chambers H.F. Fowler Jr., V.G. Evans S.R. Patel R. Klausner J.D. Antibacterial resistance leadership group: simultaneous evaluation of diagnostic assays for pharyngeal and rectal Neisseria gonorrhoeae and Chlamydia trachomatis using a master protocol.Clin Infect Dis. 2019; ([Epub ahead of print] doi:10.1093/cid/ciz1105)Crossref Scopus (13) Google Scholar The Abbott RealTime CT/NG assay is an in vitro PCR assay for direct, qualitative detection of plasmid DNA of C. trachomatis and genomic DNA of N. gonorrhoeae. The assay is currently FDA approved for testing of urogenital specimens (Abbott Molecular Inc. package insert: Abbott RealTime Chlamydia trachomatis/Neisseria gonorrhoeae Assay. Des Plaines, IL). The current study reports on the analytical performance of the Abbott Realtime CT/NG assay for detection of C. trachomatis and N. gonorrhoeae in rectal and pharyngeal specimens. All tests were performed on the Abbott m2000 RealTime system (Abbott Laboratories, Abbott Park, IL). Testing was performed by the Alameda County Department of Public Health Laboratory (Oakland, CA), except those tests performed as part of the verification process, described below. Prior interference studies for FDA approval in urogenital specimens were performed previously and not repeated in the current study (Abbott Molecular Inc. package insert: Abbott RealTime Chlamydia trachomatis/Neisseria gonorrhoeae Assay. Des Plaines, IL). All tests were performed using rectal and pharyngeal matrices purchased from a commercial laboratory (BioCollections, Miami, FL); they were obtained from asymptomatic individuals and had documentation of negative test results for C. trachomatis and N. gonorrhoeae by commercially available assays that the FDA approved for urogenital specimens. The matrices were provided in M2000 multicollection vials that were frozen at −45°C. The specimens were subsequently thawed and pooled into 50-mL volumes for testing. The limit of detection for C. trachomatis was determined by testing dilutions of C. trachomatis (Serovar LGV-II, 434 Strain, Advanced Biotechnologies Inc., Eldersburg, MD) in clinical rectal swab and pharyngeal swab matrices. The quantified stock [320 elementary bodies (EB)/mL) was obtained from a commercial laboratory (Advanced Biotechnologies Inc., Eldersburg, MD), and the elementary bodies and the DNA copy number of the stock were quantified by electron microscopy and quantitative PCR. This strain was chosen as the reference standard because it had been extensively characterized by a number of methods: PCR (genomically) quantified, the EBs were quantified by electron microscopy, and the strain is validated and known to be inactivated. The stock was subsequently diluted in a series of 10 fivefold dilutions, resulting in a range of 64 EB/mL to 3.3 × 10−5 EB/mL. To estimate the limit of detection, each dilution was tested in duplicate. Subsequently, six of the fivefold dilutions were identified across the apparent limit of detection (three above and three below) and assessed in replicates of 20 by the Abbott RealTime PCR for CT/NG on the M2000 system. The highest dilution of EB detectable in ≥95% (19 of 20) of the replicates was defined as the limit of detection. The limit of detection for N. gonorrhoeae was determined using plate counts for quantification. N. gonorrhoeae ATCC 49226 was first streaked for purity on chocolate agar. A single colony was isolated and diluted in isotonic nutrient broth in a series of 10-fold dilutions. Each dilution was split into two aliquots, with one aliquot being heat inactivated at 95°C for 15 minutes and 100 μL of the other aliquot simultaneously plated on chocolate agar plates and cultured overnight. Plate counts were then assessed in colony-forming units per milliliter (CFU/mL) to quantify the concentrations of organisms in the heat inactivated aliquot. The heat inactivated aliquot of N. gonorrhoeae corresponding to a plate count of 16 CFU/mL was used to make a series of fivefold dilutions of heat inactivated N. gonorrhoeae, ranging from 16 to 0.000205 CFU/mL, in rectal or pharyngeal matrices. Those heat inactivated aliquots of N. gonorrhoeae ATCC 49226 were evaluated on the Abbott M2000 system in replicates of at least 20. The highest dilution detectable at ≥95% frequency was defined as the limit of detection and reported in CFU/mL. Inclusivity was performed to determine whether the Abbott Realtime CT/NG Assay detected different bacterial strains. Inclusivity for C. trachomatis was performed by diluting 12 C. trachomatis serovars (A, B, C, D, E, F, G, H, I, J, K, and L2) in clinical rectal and pharyngeal swab matrices to a concentration of four times the limit of detection. Each evaluated serovar dilution was tested in 20 replicates. For N. gonorrhoeae, inclusivity was performed using seven reference isolates, four obtained from the CDC based on antimicrobial susceptibility8Centers for Disease Control and PreventionNeisseria gonorrhoeae Reference Strains for Antimicrobial Susceptibility Testing. Centers for Disease Control and Prevention, Atlanta2005Google Scholar (F-28, CDC 10328, CDC 10329, and SPL-4) and three selected from a commercially available collection (FA1090, F-18, and MHD 340; ATCC, Manassas, VA). Each strain was tested at five times the limit of detection and tested in replicates of 20. The analytical specificity (cross-reactivity) of the Abbott RealTime CT/NG assay was previously tested against an extensive list of other organisms, including Neisseria flava, Neisseria perflava, and Neisseria meningitidis types A through D, which were all found to be negative on the assay (Abbott Molecular Inc. package insert: Abbott RealTime Chlamydia trachomatis/Neisseria gonorrhoeae Assay. Des Plaines, IL). The current study evaluated an additional 28 microorganisms commonly found in the pharynx and rectum and not already evaluated in the prior cross-reactivity studies. Bacteria were tested at 2 × 106 CFU/mL. The tested concentrations for the viruses were 2.5 × 106 genomic copies per assay for Epstein-Barr virus, 2.5 × 106 DNA copies for human coxsackie virus A2 strain FI, 2.5 × 106 DNA copies for adenovirus (strain 41), and 3.0 × 106 RNA copies for norovirus (genogroup G2). All assays were performed in pharyngeal and rectal matrices known to be negative for C. trachomatis and N. gonorrhoeae. Each organism was tested once. To assess accuracy, four sets of 20 specimens were made by spiking C. trachomatis or N. gonorrhoeae to achieve concentrations of analyte 10 to 10,000 times the limit of detection in rectal and pharyngeal matrices negative for C. trachomatis and N. gonorrhoeae. The C. trachomatis specimens served as a negative control for N. gonorrhoeae and vice versa. To assess precision, large-volume specimens were created to contain an analyte concentration 10 times higher than the limit of detection and were run in quintuplicate. Replicate panels and large-volume samples were tested on the Abbott M2000 platform at BioCollections Worldwide Inc. (Miami, FL). The limit of detection of the Abbott RealTime CT/NG assay for C. trachomatis was 2.56 EB/mL in pharyngeal specimens, with all 20 specimens testing positive at this level (100%; 95% CI, 83.2%–100%), and 12.8 EB/mL in rectal specimens, with all 20 specimens testing positive at this level (100%; 95% CI, 83.2%–100%). The limit of detection for N. gonorrhoeae was 0.0256 CFU/mL for both pharyngeal and rectal specimens, with 19 pharyngeal specimens (95%; 95% CI, 75.1%–99.9%) and 20 rectal specimens (100%; 95% CI, 83.2%–100%) testing positive at this level (Table 1).Table 1Serial Dilutions of Chlamydia trachomatis and Neisseria gonorrhoeae in Rectal and Pharyngeal Specimens Used to Determine the Limit of Detection of the Abbott RealTime CT/NG AssayAssay typeSourceConcentration∗Concentrations are given in elementary bodies per milliliter (EB/mL) for C. trachomatis and colony-forming units per milliliter (CFU/mL) for N. gonorrhoeae.No. of positive samplesNo. of negative samplesPercentage of positive samples (95% CI)Chlamydia trachomatis (EB/mL)Pharyngeal320200100.0 (83.2–100.0)64200100.0 (83.2–100.0)12.8200100.0 (83.2–100.0)2.56200100.0 (83.2–100.0)0.51217385.0 (62.1–96.8)0.10240200.0 (0.0–16.8)0.020480220.0 (0.0–15.4)0.0040960190.0 (0.0–17.7)Rectal320200100.0 (83.2–100.0)64210100.0 (83.9–100.0)12.8200100.0 (83.2–100.0)2.5618290.0 (68.3–98.8)0.51216480.0 (56.3–94.3)0.102451525.0 (8.7–49.1)0.0204831715.0 (3.2–37.9)0.0040960200.0 (0.0–16.8)0.00081920200.0 (0.0–16.8)Neisseria gonorrhoeae [CFU/mL]Pharyngeal1660100.0 (54.1–100.0)3.2220100.0 (84.6–100.0)0.64210100.0 (83.9–100.0)0.128200100.0 (83.2–100.0)0.025619195.0 (75.1–99.9)0.0051241620.0 (5.7–43.7)0.0010240200.0 (0.0–16.8)0.0002050200.0 (0.0–16.8)Rectal1660100.0 (54.1–100.0)3.2210100.0 (83.9–100.0)0.64210100.0 (83.9–100.0)0.128200100.0 (83.2–100.0)0.0256200100.0 (83.2–100.0)0.0051221810.0 (1.2–31.7)0.0010241195.0 (0.1–24.9)0.0002050200.0 (0.0–16.8)Bold values indicate the limit of detection, where ≥95% of the replicates were detected.∗ Concentrations are given in elementary bodies per milliliter (EB/mL) for C. trachomatis and colony-forming units per milliliter (CFU/mL) for N. gonorrhoeae. Open table in a new tab Bold values indicate the limit of detection, where ≥95% of the replicates were detected. The inclusivity for C. trachomatis was 100% because all 12 C. trachomatis serovars tested at four times the limit of detection were detected in 100% (20 of 20) rectal and pharyngeal matrices. The inclusivity for N. gonorrhoeae also achieved 100% (20 of 20) inclusivity for detection of each of the seven strains tested. In total, there were 28 microorganisms spiked into both pharyngeal and rectal specimens and tested by the Abbott RealTime CT/NG assay. There was no cross-reactivity observed, corresponding to an analytical specificity of 100% (Table 2).Table 2Analytical Specificity of Abbott RealTime CT/NG Assay against 28 Bacteria and Viruses in Rectal and Pharyngeal MatricesMicroorganismConcentrationPharyngeal specimensRectal specimensChlamydia trachomatisNeisseria gonorrhoeaeChlamydia trachomatisNeisseria gonorrhoeaeAcinetobacter baumannii1.0 × 106 cells/assayNegativeNegativeNegativeNegativeArcanobacterium hemolyticum1.0 × 106 cells/assayNegativeNegativeNegativeNegativeAdenovirus2.5 × 106 DNA copies/assayNegativeNegativeNegativeNegativeBacteroides oralis1.0 × 106 cells/assayNegativeNegativeNegativeNegativeBordetella pertussis1.0 × 106 cells/assayNegativeNegativeNegativeNegativeBurkholderia cepacia1.0 × 106 cells/assayNegativeNegativeNegativeNegativeCampylobacter rectus1.0 × 106 cells/assayNegativeNegativeNegativeNegativeCitrobacter koseri1.0 × 106 cells/assayNegativeNegativeNegativeNegativeClostridium difficile1.0 × 106 cells/assayNegativeNegativeNegativeNegativeCorynebacterium diphtheriae1.0 × 106 cells/assayNegativeNegativeNegativeNegativeCorynebacterium pseudodiphtheriticum1.0 × 106 cells/assayNegativeNegativeNegativeNegativeEnterovirus2.5 × 106 DNA copies/assayNegativeNegativeNegativeNegativeEpstein-Barr virus2.5 × 106 genomic copies/assayNegativeNegativeNegativeNegativeFusobacterium necrophorum1.0 × 106 cells/assayNegativeNegativeNegativeNegativeHemophilus parahaemolyticus1.0 × 106 cells/assayNegativeNegativeNegativeNegativeHemophilus parainfluenzae1.0 × 106 cells/assayNegativeNegativeNegativeNegativeHelicobacter pylori1.0 × 106 cells/assayNegativeNegativeNegativeNegativeLegionella micdadei1.0 × 1066 cells/assayNegativeNegativeNegativeNegativeNeisseria meningitidis1.0 × 106 cells/assayNegativeNegativeNegativeNegativeNorovirus3.0 × 106 RNA copies/assayNegativeNegativeNegativeNegativePeptostreptococcus micros1.0 × 106 cells/assayNegativeNegativeNegativeNegativeProvidencia alcalifaciens1.0 × 106 cells/assayNegativeNegativeNegativeNegativeStaphylococcus hemolyticus1.0 × 106 cells/assayNegativeNegativeNegativeNegativeStenotrophomonas maltophilia1.0 × 106 cells/assayNegativeNegativeNegativeNegativeStreptococcus anginosus group1.0 × 106 cells/assayNegativeNegativeNegativeNegativeStreptococcus bovis1.0 × 106 cells/assayNegativeNegativeNegativeNegativeStreptococcus mitis1.0 × 106 cells/assayNegativeNegativeNegativeNegativeVeillonella parvula1.0 × 106 cells/assayNegativeNegativeNegativeNegative Open table in a new tab In total, there were 80 specimens tested by the second laboratory. All 40 rectal and pharyngeal specimens spiked with C. trachomatis and all 40 rectal and pharyngeal specimens spiked with N. gonorrhoeae tested positive. C. trachomatis was detected in 0 of the 20 N. gonorrhoeae–spiked samples from each anatomic site and N. gonorrhoeae was detected in 0 of the 20 C. trachomatis–spiked samples from each anatomic site. For the precision testing, all 10 specimens spiked with C. trachomatis (100%) tested positive; all 10 specimens spiked with N. gonorrhoeae also tested positive by the external laboratory. This study reports the findings of an analytical evaluation of the Abbott RealTime CT/NG assay for detection of C. trachomatis and N. gonorrhoeae in rectal and pharyngeal specimens. The findings indicate that the assay had 100% inclusivity and specificity among the serotypes and microorganisms tested and that it performed well in the verification study, with 100% accuracy and precision among specimens tested. In addition, the assay was able to detect low bacterial loads. The limits of detection claim for the Abbott RealTime CT/NG assay in urogenital specimens is 320 copies of C. trachomatis target DNA and 320 copies of N. gonorrhoeae target DNA per assay, corresponding to approximately 30 to 40 organisms per assay (Abbott Molecular Inc. package insert: Abbott RealTime Chlamydia trachomatis/Neisseria gonorrhoeae Assay. Des Plaines, IL). Results of the current study showed the limit of detection for C. trachomatis to be 12.8 EB/mL in rectal specimens, 2.56 EB/mL in pharyngeal specimens, and 0.0256 CFU/mL in both rectal and pharyngeal specimens for N. gonorrhoeae. Although it is difficult to compare precisely copies of DNA with EB or CFU, these findings suggest that the limits of detection for C. trachomatis and N. gonorrhoeae in rectal and pharyngeal specimens are similar or slightly lower than the reported claims for the Abbott RealTime CT/NG assay in urogenital specimens. The limits of detection of the Abbott RealTime CT/NG assay for C. trachomatis in both rectal and pharyngeal specimens were somewhat lower than those reported by another PCR-based assay, the Xpert CT/NG assay (Cepheid, CA), an assay for rectal and pharyngeal specimens. The Xpert CT/NG assay limit of detection was to EB/mL in rectal and to EB/mL in pharyngeal specimens by package insert: Xpert For N. gonorrhoeae, the limit of detection on the Abbott RealTime CT/NG assay was to be 0.0256 CFU/mL in both rectal and pharyngeal specimens, which also to the Xpert CT/NG assay, with limits of detection reported to be to CFU/mL in rectal specimens and to CFU/mL in pharyngeal specimens by package insert: Xpert The limits of detection for both assays were performed on heat inactivated specimens corresponding to a CFU/mL broth The of the assay in copies each and are at heat it to detect CFU/mL, which is a method for of In addition, limit of detection data from the Abbott RealTime CT/NG assay also compare with other PCR for the detection of C. trachomatis and N. gonorrhoeae in and specimens. For the assay a limit of detection as low as to 100 EB/mL in specimens for C. trachomatis and as low as to in specimens for N. gonorrhoeae and package insert: Assay. studies have evaluated the bacterial associated with N. gonorrhoeae and C. trachomatis infections at rectal and pharyngeal In M. Neisseria gonorrhoeae bacterial in the pharynx and rectum in men who have sex with for gonococcal detection, and PubMed Scopus Google Scholar found that bacterial of N. gonorrhoeae obtained from were higher in the rectum copies per with the pharynx copies per and highest among men with of copies per D. Neisseria gonorrhoeae bacterial DNA in the and of men who have sex with PubMed Scopus Google Scholar reported a copies per swab among men testing positive by nucleic acid amplification tests. In a that assessed bacterial for C. R. W.M. The of Chlamydia trachomatis organism a Infect Dis. 2015; PubMed Scopus Google Scholar found of bacterial by anatomic and which limits However, recently, D. G. R. of Chlamydia trachomatis in the and among men who have sex with men with oropharyngeal 2019; ([Epub ahead of print] PubMed Scopus Google Scholar evaluated bacterial of C. trachomatis in and found a of copies per swab in the studies that evaluated C. trachomatis bacterial in rectal infections found similar with a of C. trachomatis among and Chlamydia trachomatis bacterial in infected a 2019; PubMed Scopus Google Scholar and of C. trachomatis among and who reported Chlamydia trachomatis is similar in men who have sex with men and 2015; PubMed Scopus Google Scholar recent study found higher bacterial in rectal infections with pharyngeal infections and no men and tested reported and have an oropharyngeal and Chlamydia trachomatis bacterial a of anatomic Infect Dis. 2019; ([Epub ahead of print] PubMed Scopus Google Scholar Although it is difficult to the number of bacteria to infections at these the limit of detection for the Abbott RealTime CT/NG assay reported be to detect infections for the bacterial in those The clinical performance of the Abbott RealTime CT/NG in rectal and pharyngeal specimens was evaluated in a study of and asymptomatic two other assays that have been FDA approved for detection of C. trachomatis and N. gonorrhoeae at rectal and pharyngeal S.B. Komarow L. Tran T.T.T. Sund Z. Pandori M.W. Jensen D. Tsalik E.L. Deal C.D. Chambers H.F. Fowler Jr., V.G. Evans S.R. Patel R. Klausner J.D. Antibacterial resistance leadership group: simultaneous evaluation of diagnostic assays for pharyngeal and rectal Neisseria gonorrhoeae and Chlamydia trachomatis using a master protocol.Clin Infect Dis. 2019; ([Epub ahead of print] doi:10.1093/cid/ciz1105)Crossref Scopus (13) Google Scholar The negative of the Abbott RealTime CT/NG assay was and for N. gonorrhoeae at pharyngeal and rectal and and for C. trachomatis at pharyngeal and rectal Those were similar to the other two assays tested and to high sensitivity of the The limit of detection findings also support the high sensitivity of the The data demonstrate that the Abbott CT/NG RealTime assay is an accurate, sensitive, and assay in rectal and pharyngeal specimens. These clinical performance support potential claims of use of the assay for detection of C. trachomatis and N. gonorrhoeae infections in rectal and pharyngeal specimens. the of the and the for their with data and