Test characteristics and potential impact of the urine LAM lateral flow assay in HIV-infected outpatients under investigation for TB and able to self-expectorate sputum for diagnostic testing

dc.contributor.authorPeter, Jonnyen_ZA
dc.contributor.authorTheron, Granten_ZA
dc.contributor.authorChanda, Duncanen_ZA
dc.contributor.authorClowes, Petraen_ZA
dc.contributor.authorRachow, Andreaen_ZA
dc.contributor.authorLesosky, Maiaen_ZA
dc.contributor.authorHoelscher, Michaelen_ZA
dc.contributor.authorMwaba, Peteren_ZA
dc.contributor.authorPym, Alexen_ZA
dc.contributor.authorDheda, Keertanen_ZA
dc.contributor.authorFor the TB-NEAT teamen_ZA
dc.date.accessioned2015-12-07T08:52:11Z
dc.date.available2015-12-07T08:52:11Z
dc.date.issued2015en_ZA
dc.description.abstractBACKGROUND: The commercially available urine LAM strip test, a point-of-care tuberculosis (TB) assay, requires evaluation in a primary care setting where it is most needed. There is currently inadequate data to guide implementation in TB and HIV-endemic settings. METHODS: Adult HIV-infected outpatients with suspected pulmonary TB able to self-expectorate sputum from four primary clinics in South Africa, Zambia and Tanzania underwent diagnostic evaluation [sputum smear microscopy, Xpert-MTB/RIF, and culture (reference standard)] as part of a prospective parent study. Urine LAM testing (grade-2 cut-point) was performed on archived samples. Performance characteristics of LAM alone or in combination with sputum--based diagnostics were evaluated. Potential impact on 2 and 6-month morbidity (TBscore), patient dropout rates, and prognosis (death/ loss to follow-up) were evaluated. RESULTS: Among 583 participants with suspected TB that were HIV-infected or refused testing, the overall LAM sensitivity (95 % CI; n/N) and in the CD4[less than or equal to]100 cells/mm 3 sub-group was 22.7 % (16.6-28.7; 41/181) and 30.4 % (17.1-43.7; 14/46), respectively. Overall specificity was 93.0 % (90.5-95.6; 361/388). Amongst culture-positive TB cases, adjunctive LAM testing did not improve the sensitivity of either sputum Xpert-MTB/RIF [78.2 % (69.8-86.7; 72/92) versus 76.1 % (67.4-84.8; 70/92), p=0.7] or smear-microscopy [56.2 % (45.9-66.5; 50/89) versus 43.8 % (33.5-54.1; 39/89), p=0.1). Clinic-based LAM, as an adjunct to either smear microscopy or Xpert MTB/RIF same-day testing, would neither have decreased patient dropout, nor increased same-day treatment initiation in this clinical setting where same-day chest radiography was available. LAM positivity was associated with 6-month lost-to-follow-up/death (AOR 4.4; p=0.002) but not TBscore (at baseline or change in TBscore 2-months post-treatment) (p=0.17). CONCLUSIONS: In African HIV-TB co-infected outpatients able to self-expectorate sputum LAM had limited sensitivity even at low CD4 counts, and offered no significant incremental diagnostic yield over Xpert-MTB/RIF or smear microscopy. In primary care clinics with chest radiography and where empiric TB treatment is common, LAM seems unlikely to improve rates of same-day treatment initiation and patient dropout, however, the ability of LAM to identify patients at high risk of death or lost-to-follow-up may offer important prognostic value.en_ZA
dc.identifier.apacitationPeter, J., Theron, G., Chanda, D., Clowes, P., Rachow, A., Lesosky, M., ... (2015). Test characteristics and potential impact of the urine LAM lateral flow assay in HIV-infected outpatients under investigation for TB and able to self-expectorate sputum for diagnostic testing. <i>BMC Infectious Diseases</i>, http://hdl.handle.net/11427/15650en_ZA
dc.identifier.chicagocitationPeter, Jonny, Grant Theron, Duncan Chanda, Petra Clowes, Andrea Rachow, Maia Lesosky, Michael Hoelscher, et al "Test characteristics and potential impact of the urine LAM lateral flow assay in HIV-infected outpatients under investigation for TB and able to self-expectorate sputum for diagnostic testing." <i>BMC Infectious Diseases</i> (2015) http://hdl.handle.net/11427/15650en_ZA
dc.identifier.citationPeter, J., Theron, G., Chanda, D., Clowes, P., Rachow, A., Lesosky, M., ... & Dheda, K. (2015). Test characteristics and potential impact of the urine LAM lateral flow assay in HIV-infected outpatients under investigation for TB and able to self-expectorate sputum for diagnostic testing. BMC infectious diseases, 15(1), 262.en_ZA
dc.identifier.ris TY - Journal Article AU - Peter, Jonny AU - Theron, Grant AU - Chanda, Duncan AU - Clowes, Petra AU - Rachow, Andrea AU - Lesosky, Maia AU - Hoelscher, Michael AU - Mwaba, Peter AU - Pym, Alex AU - Dheda, Keertan AU - For the TB-NEAT team AB - BACKGROUND: The commercially available urine LAM strip test, a point-of-care tuberculosis (TB) assay, requires evaluation in a primary care setting where it is most needed. There is currently inadequate data to guide implementation in TB and HIV-endemic settings. METHODS: Adult HIV-infected outpatients with suspected pulmonary TB able to self-expectorate sputum from four primary clinics in South Africa, Zambia and Tanzania underwent diagnostic evaluation [sputum smear microscopy, Xpert-MTB/RIF, and culture (reference standard)] as part of a prospective parent study. Urine LAM testing (grade-2 cut-point) was performed on archived samples. Performance characteristics of LAM alone or in combination with sputum--based diagnostics were evaluated. Potential impact on 2 and 6-month morbidity (TBscore), patient dropout rates, and prognosis (death/ loss to follow-up) were evaluated. RESULTS: Among 583 participants with suspected TB that were HIV-infected or refused testing, the overall LAM sensitivity (95 % CI; n/N) and in the CD4[less than or equal to]100 cells/mm 3 sub-group was 22.7 % (16.6-28.7; 41/181) and 30.4 % (17.1-43.7; 14/46), respectively. Overall specificity was 93.0 % (90.5-95.6; 361/388). Amongst culture-positive TB cases, adjunctive LAM testing did not improve the sensitivity of either sputum Xpert-MTB/RIF [78.2 % (69.8-86.7; 72/92) versus 76.1 % (67.4-84.8; 70/92), p=0.7] or smear-microscopy [56.2 % (45.9-66.5; 50/89) versus 43.8 % (33.5-54.1; 39/89), p=0.1). Clinic-based LAM, as an adjunct to either smear microscopy or Xpert MTB/RIF same-day testing, would neither have decreased patient dropout, nor increased same-day treatment initiation in this clinical setting where same-day chest radiography was available. LAM positivity was associated with 6-month lost-to-follow-up/death (AOR 4.4; p=0.002) but not TBscore (at baseline or change in TBscore 2-months post-treatment) (p=0.17). CONCLUSIONS: In African HIV-TB co-infected outpatients able to self-expectorate sputum LAM had limited sensitivity even at low CD4 counts, and offered no significant incremental diagnostic yield over Xpert-MTB/RIF or smear microscopy. In primary care clinics with chest radiography and where empiric TB treatment is common, LAM seems unlikely to improve rates of same-day treatment initiation and patient dropout, however, the ability of LAM to identify patients at high risk of death or lost-to-follow-up may offer important prognostic value. DA - 2015 DB - OpenUCT DO - 10.1186/s12879-015-0967-z DP - University of Cape Town J1 - BMC Infectious Diseases LK - https://open.uct.ac.za PB - University of Cape Town PY - 2015 T1 - Test characteristics and potential impact of the urine LAM lateral flow assay in HIV-infected outpatients under investigation for TB and able to self-expectorate sputum for diagnostic testing TI - Test characteristics and potential impact of the urine LAM lateral flow assay in HIV-infected outpatients under investigation for TB and able to self-expectorate sputum for diagnostic testing UR - http://hdl.handle.net/11427/15650 ER - en_ZA
dc.identifier.urihttp://hdl.handle.net/11427/15650
dc.identifier.urihttp://dx.doi.org/10.1186/s12879-015-0967-z
dc.identifier.vancouvercitationPeter J, Theron G, Chanda D, Clowes P, Rachow A, Lesosky M, et al. Test characteristics and potential impact of the urine LAM lateral flow assay in HIV-infected outpatients under investigation for TB and able to self-expectorate sputum for diagnostic testing. BMC Infectious Diseases. 2015; http://hdl.handle.net/11427/15650.en_ZA
dc.language.isoengen_ZA
dc.publisherBioMed Central Ltden_ZA
dc.publisher.departmentDepartment of Medicineen_ZA
dc.publisher.facultyFaculty of Health Sciencesen_ZA
dc.publisher.institutionUniversity of Cape Town
dc.rightsThis is an Open Access article distributed under the terms of the Creative Commons Attribution Licenseen_ZA
dc.rights.holder2015 Peter et al.en_ZA
dc.rights.urihttp://creativecommons.org/licenses/by/4.0en_ZA
dc.sourceBMC Infectious Diseasesen_ZA
dc.source.urihttp://www.biomedcentral.com/bmcinfectdis/en_ZA
dc.subject.otherDivision of Pulmonologyen_ZA
dc.titleTest characteristics and potential impact of the urine LAM lateral flow assay in HIV-infected outpatients under investigation for TB and able to self-expectorate sputum for diagnostic testingen_ZA
dc.typeJournal Articleen_ZA
uct.type.filetypeText
uct.type.filetypeImage
uct.type.publicationResearchen_ZA
uct.type.resourceArticleen_ZA
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