Improving point-of-care diagnosis of tuberculosis: development and evaluation of novel technologies

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dc.contributor.advisorNicol, Mark Pen_ZA
dc.contributor.advisorDorman, Susan Een_ZA
dc.contributor.authorMoodley, Vineshree Mischkaen_ZA
dc.date.accessioned2017-09-28T05:24:46Z
dc.date.available2017-09-28T05:24:46Z
dc.date.issued2017en_ZA
dc.description.abstractWith an estimated third of all tuberculosis (TB) cases being missed, the need to develop rapid, simple and accurate diagnostic tests is critical. The last five years has seen an unprecedented activity in the development of a range of new tests. However, a major concern is that not all marketed TB tests have been assessed rigorously, particularly in terms of diagnostic accuracy, robustness under operational conditions in the field, and practical usefulness. This dissertation comprises a compilation of diagnostic clinical studies of novel point-of-care tests, namely a chemiresistive "TB breath-analyser"; a lipoarabinomannan (LAM) urine dipstick, and an adaptation of the Xpert®MTB/RIF assay for use on blood. Lastly, there is a modification of the sputum collection device (SCD) to enable specimen processing without the requirement of a biosafety cabinet. The chemiresistive sensor, which detects volatile organic compounds released by Mycobacterium tuberculosis in a patient's breath, demonstrated a high sensitivity (100%) and specificity (92%) for distinguishing patients with active TB from healthy controls. However, sensitivity (74%) and specificity (63%) were lower when the culture-negative participant group was compared to the culture-positive participants. The test shows potential as a useful screening test for TB with further refinement of the sensor technology. The LAM dipstick was shown to be useful in hospitalised HIV-infected patients with CD4 T-cell counts <200 cells/μL reinforcing the data from other studies. Although the blood Xpert®MTB/RIF assay showed some utility in diagnosis of TB in hospitalised patients with very advanced HIV, given the poor sensitivity and specificity, and the requirement for specialised equipment as well as a large volume of blood for testing, it is unlikely that Xpert®MTB/RIF testing on blood will contribute much over other existing diagnostics in resource-limited settings. Finally, the redesigned SCD offers a solution to biosafety concerns with minimal impact on patient acceptability and clinical care.en_ZA
dc.identifier.apacitationMoodley, V. M. (2017). <i>Improving point-of-care diagnosis of tuberculosis: development and evaluation of novel technologies</i>. (Thesis). University of Cape Town ,Faculty of Health Sciences ,Division of Medical Microbiology. Retrieved from http://hdl.handle.net/11427/25439en_ZA
dc.identifier.chicagocitationMoodley, Vineshree Mischka. <i>"Improving point-of-care diagnosis of tuberculosis: development and evaluation of novel technologies."</i> Thesis., University of Cape Town ,Faculty of Health Sciences ,Division of Medical Microbiology, 2017. http://hdl.handle.net/11427/25439en_ZA
dc.identifier.citationMoodley, V. 2017. Improving point-of-care diagnosis of tuberculosis: development and evaluation of novel technologies. University of Cape Town.en_ZA
dc.identifier.ris TY - Thesis / Dissertation AU - Moodley, Vineshree Mischka AB - With an estimated third of all tuberculosis (TB) cases being missed, the need to develop rapid, simple and accurate diagnostic tests is critical. The last five years has seen an unprecedented activity in the development of a range of new tests. However, a major concern is that not all marketed TB tests have been assessed rigorously, particularly in terms of diagnostic accuracy, robustness under operational conditions in the field, and practical usefulness. This dissertation comprises a compilation of diagnostic clinical studies of novel point-of-care tests, namely a chemiresistive "TB breath-analyser"; a lipoarabinomannan (LAM) urine dipstick, and an adaptation of the Xpert®MTB/RIF assay for use on blood. Lastly, there is a modification of the sputum collection device (SCD) to enable specimen processing without the requirement of a biosafety cabinet. The chemiresistive sensor, which detects volatile organic compounds released by Mycobacterium tuberculosis in a patient's breath, demonstrated a high sensitivity (100%) and specificity (92%) for distinguishing patients with active TB from healthy controls. However, sensitivity (74%) and specificity (63%) were lower when the culture-negative participant group was compared to the culture-positive participants. The test shows potential as a useful screening test for TB with further refinement of the sensor technology. The LAM dipstick was shown to be useful in hospitalised HIV-infected patients with CD4 T-cell counts <200 cells/μL reinforcing the data from other studies. Although the blood Xpert®MTB/RIF assay showed some utility in diagnosis of TB in hospitalised patients with very advanced HIV, given the poor sensitivity and specificity, and the requirement for specialised equipment as well as a large volume of blood for testing, it is unlikely that Xpert®MTB/RIF testing on blood will contribute much over other existing diagnostics in resource-limited settings. Finally, the redesigned SCD offers a solution to biosafety concerns with minimal impact on patient acceptability and clinical care. DA - 2017 DB - OpenUCT DP - University of Cape Town LK - https://open.uct.ac.za PB - University of Cape Town PY - 2017 T1 - Improving point-of-care diagnosis of tuberculosis: development and evaluation of novel technologies TI - Improving point-of-care diagnosis of tuberculosis: development and evaluation of novel technologies UR - http://hdl.handle.net/11427/25439 ER - en_ZA
dc.identifier.urihttp://hdl.handle.net/11427/25439
dc.identifier.vancouvercitationMoodley VM. Improving point-of-care diagnosis of tuberculosis: development and evaluation of novel technologies. [Thesis]. University of Cape Town ,Faculty of Health Sciences ,Division of Medical Microbiology, 2017 [cited yyyy month dd]. Available from: http://hdl.handle.net/11427/25439en_ZA
dc.language.isoengen_ZA
dc.publisher.departmentDivision of Medical Microbiologyen_ZA
dc.publisher.facultyFaculty of Health Sciencesen_ZA
dc.publisher.institutionUniversity of Cape Town
dc.subject.otherPathologyen_ZA
dc.subject.otherMedical Microbiologyen_ZA
dc.titleImproving point-of-care diagnosis of tuberculosis: development and evaluation of novel technologiesen_ZA
dc.typeDoctoral Thesis
dc.type.qualificationlevelDoctoral
dc.type.qualificationnamePhDen_ZA
uct.type.filetypeText
uct.type.filetypeImage
uct.type.publicationResearchen_ZA
uct.type.resourceThesisen_ZA
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