Molecular test for chlamydia and gonorrhoea used at point of care in remote primary healthcare settings: a diagnostic test evaluation

Causer, Louise; Guy, Rebecca; Tabrizi, Sepehr N.; Whiley, David M.; Speers, David; Ward, James; Tangey, Annie; Badman, Steven G; Hengel, Belinda; Natoli, Lisa; Anderson, David A.; Wand, Handan; Wilson, David; Regan, David G.; Shephard, Mark; Donovan, Basil; Fairley, Christopher K.; Kaldor, John

doi:10.1136/sextrans-2017-053443

Cited by 45 publications

(34 citation statements)

References 29 publications

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“…Several studies have shown that this can be used in settings with basic laboratory infrastructure. The utility of GeneXpert has been evaluated in remote populations such as an aboriginal community in Australia ; in routine antenatal care in Papua New Guinea (with STI rates by GeneXpert of CT 20%, NG 11.2% and TV 37.6%) ; in HIV‐infected pregnant women in South Africa (40.2% with STIs) . Another utility study in South Africa in HIV‐negative women presenting for STI care or with symptoms (CT 18.4%, NG 5.2%, TV 3%) resulted in STI testing of symptomatic and asymptomatic women and the same‐day treatment, with expedited partner treatment and reduced reinfection after six months .…”

Section: Resultsmentioning

confidence: 99%

Diagnosing sexually transmitted infections in resource‐constrained settings: challenges and ways forward

Ndowa²,

et al. 2019

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Introduction Sexually transmitted infections (STIs) remain prevalent and are increasing in several populations. Appropriate STI diagnosis is crucial to prevent the transmission and sequelae of untreated infection. We reviewed the diagnostic accuracy of syndromic case management and existing point‐of‐care tests (POCTs), including those in the pipeline, to diagnose STIs in resource‐constrained settings. Methods We prioritized updating the systematic review and meta‐analysis of the diagnostic accuracy of vaginal discharge from 2001 to 2015 to include studies until 2018. We calculated the absolute effects of different vaginal flowcharts and the diagnostic performance of POCTs on important outcomes. We searched the peer‐reviewed literature for previously conducted systematic reviews and articles from 1990 to 2018 on the diagnostic accuracy of syndromic management of vaginal and urethral discharge, genital ulcer and anorectal infections. We conducted literature reviews from 2000 to 2018 on the existing POCTs and those in the pipeline. Results and discussions The diagnostic accuracy of urethral discharge and genital ulcer disease syndromes is relatively adequate. Asymptomatic Chlamydia trachomatis (CT) and Neisseria gonorrhoeae (NG) infections limit the use of vaginal discharge and anorectal syndromes. The pooled diagnostic accuracy of vaginal syndromic case management for CT/NG is low, resulting in high numbers of overtreatment and missed treatment. The absolute effect of POCTs was reduced overtreatment and missed treatment. Findings of the reviews on syndromic case management underscored the need for low‐cost and accurate POCTs for the identification, first, of CT/NG, and, second, of Mycoplasma genitalium (MG) and Trichomonas vaginalis (TV) and NG and MG resistance/susceptibility testing. Near‐patient POCT molecular assays for CT/NG/TV are commercially available. The prices of these POCTs remain the barrier for uptake in resource‐constrained settings. This is driving the development of lower cost solutions. Conclusions The WHO syndromic case management guidelines should be updated to raise the quality of STI management through the integration of laboratory tests. STI screening strategies are needed to address asymptomatic STIs. POCTs that are accurate, rapid, simple and affordable are urgently needed in resource‐constrained settings to support the uptake of aetiological diagnosis and treatment.

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Section: Resultsmentioning

confidence: 99%

Diagnosing sexually transmitted infections in resource‐constrained settings: challenges and ways forward

Ndowa²,

et al. 2019

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“…The present work has certainly demonstrated that assay type can drive discordance, so specific evaluation of other and novel assays is warranted when considering whether (13). Clearly, POC testing does not rely on confirmation of the result at a reference laboratory, and growing interest in POC testing is evident in new technologies and quality processes to support this approach (14)(15)(16).…”

Section: Discussionmentioning

confidence: 88%

Factors That Influence Confirmation of Neisseria gonorrhoeae Positivity by Molecular Methods

et al. 2019

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Several Neisseria gonorrhoeae nucleic acid amplification tests (NAATs) with high sensitivity exist. However, the specificity of N. gonorrhoeae NAATs may be suboptimal, particularly for extragenital biospecimens. Consequently, confirmation with a second NAAT is common, although this represents a burden on resources. Furthermore, the rationale for confirmation is contentious. The objective of this work was to assess N. gonorrhoeae confirmation in over 13,000 N. gonorrhoeae screenpositive samples representing various biospecimens and three separate screening assays, the Abbott RealTime CT/NG (Abbott Molecular, Inc., Des Plaines, IL), the Cobas CT/NG test (Roche Molecular Systems Inc., Alameda, CA), and the BD ProbeTec ET CT/GC amplified DNA assay (BD Diagnostics, Sparks, MD). Factors predictive of confirmation were determined via logistic regression involving sex, year, whether the sample was formally validated, and sample site. Level of confirmation varied according to screening assay (96.2%, 86.0%, and 73.9% for the Abbott, Roche, and BD tests, respectively) in sample types formally included according to the manufacturers' instructions (i.e., validated). Sex did not affect confirmation for 2/3 assays, and the likelihood of confirmation of samples not formally included in manufacturer instructions (i.e., nonvalidated) was 89.1%, 82.1%, and 59.2% for the Abbott, Roche, and BD tests, respectively. Rectal swabs, which are nonvalidated samples, confirmed in 91.5%, 90.1%, and 87.4% of samples initially tested with the respective assays. The requirement to confirm N. gonorrhoeae in validated samples is not required for all NAATs, although initial assay-specific evaluation is justified given observed variability. Rectal samples represent robust biospecimens for N. gonorrhoeae NAAT testing and may not require confirmation when screened with the assays described.T he management of Neisseria gonorrhoeae infection represents an increasing and significant clinical burden in various settings, including the United Kingdom. ln Scotland in 2017, there were 2,610 episodes of gonorrhea, in comparison with only 1,073 cases in 2008 (1). Similar observations of an increase over the last decade have also been noted in England (2).Quantification of the magnitude of the increase as a result of changed sexual behaviors and/or shortfalls in management approaches is confounded by variability in indications for testing and the increased use of highly sensitive nucleic acid amplification tests (NAATs). Consistency of recommendations for testing practices and application of robust NAATs can support the more accurate measurement of genuine trends. Certainly, NAAT rather than culture of N. gonorrhoeae is recommended as a first-line test, and an increasing diversity of molecular tests exists. Assay-driven influences in NAAT confirmation of N. gonorrhoeae have been reported, including in a recent UK study, where 27% of samples from females did not confirm with a second-line test (3).

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“…In keeping with our findings, the assay demonstrated a high sensitivity and specificity when performed by nurses and community health workers compared with conventional NAATs for both CT (98.6%, 99.5%) and NG (100%, 99.9%) using either urine samples or vaginal swabs. The authors concluded that this POC STI assay may be particularly suitable for LMICs, where resources are limited and infrastructure is often poor 9…”

Section: Discussionmentioning

confidence: 99%

“…These experiences by patients led to the study design, and the implementation of POC testing and EPT in the clinic. Patients took part in focus group discussions and were able to provide feedback to the study team on their experiences with the POC STI testing model 9…”

Section: Methodsmentioning

confidence: 99%

Diagnostic accuracy of the Xpert CT/NG and OSOM Trichomonas Rapid assays for point-of-care STI testing among young women in South Africa: a cross-sectional study

et al. 2019

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ObjectivesSyndromic management of sexually transmitted infections (STIs) omits asymptomatic infections, particularly among women. Accurate point-of-care assays may improve STI care in low- and middle-income countries (LMICs). We aimed to evaluate the diagnostic performance of the XpertChlamydia trachomatis/Neisseria gonorrhoeae(CT/NG) and OSOMTrichomonas vaginalis(TV) Test as part of a STI care model for young women in South Africa.DesignDiagnostic evaluation conducted as part of a prospective cohort study (CAPRISA 083) between May 2016 and January 2017.SettingOne large public healthcare facility in central Durban, KwaZulu-Natal, South AfricaParticipants247 women, aged 18–40 years, attending for sexual and reproductive services to the clinic. Pregnant and HIV-positive women were excluded.OutcomesDiagnostic performance of the Xpert CT/NG and OSOM TV assays against the laboratory-based Anyplex II STI-7 Detection. All discordant results were further tested on the Fast Track Diagnostics (FTD) STD9 assay.ResultsWe obtained vaginal swabs from 247 women and found 96.8% (239/247) concordance between Xpert and Anyplex for CT and 100% (247/247) for NG. All eight discrepant CT results were positive on Xpert, but negative on Anyplex. FTD STD9 confirmed three positive and five negative results, giving a confirmed prevalence of CT 15.0% (95% CI 10.5 to 19.4), NG 4.9% (2.2–7.5) and TV 3.2% (1.0–5.4). Sensitivity and specificity of Xpert CT/NG were 100% (100-100) and 97.6% (95.6–99.7) for CT and 100% (100-100) and 100% (100-100) for NG. The sensitivity and specificity of OSOM TV were 75.0% (45.0–100) and 100% (100-100).ConclusionThe Xpert CT/NG showed high accuracy among young South African women and combined with the OSOM TV proved a useful tool in this high HIV/STI burden setting. Further implementation and cost-effectiveness studies are needed to assess the potential role of this assay for diagnostic STI testing in LMICs.Trial registration numberNCT03407586; Pre-results.

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Molecular test for chlamydia and gonorrhoea used at point of care in remote primary healthcare settings: a diagnostic test evaluation

Cited by 45 publications

References 29 publications

Diagnosing sexually transmitted infections in resource‐constrained settings: challenges and ways forward

Diagnosing sexually transmitted infections in resource‐constrained settings: challenges and ways forward

Factors That Influence Confirmation of Neisseria gonorrhoeae Positivity by Molecular Methods

Diagnostic accuracy of the Xpert CT/NG and OSOM Trichomonas Rapid assays for point-of-care STI testing among young women in South Africa: a cross-sectional study

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