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Spooner E, Reddy S, Ntoyanto S, Sakadavan Y, Reddy T, Mahomed S, Mlisana K, Dlamini M, Daniels B, Luthuli N, Ngomane N, Kiepiela P, Coutsoudis A. TB testing in HIV-positive patients prior to antiretroviral treatment. Int J Tuberc Lung Dis 2022; 26:224-231. [PMID: 35197162 PMCID: PMC8886959 DOI: 10.5588/ijtld.21.0195] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND: TB diagnosis in patients with HIV is challenging due to the lower sensitivities across tests. Molecular tests are preferred and the Xpert® MTB/RIF assay has limitations in lower-income settings. We evaluated the performance of loop-mediated isothermal amplification (LAMP) and the lipoarabinomannan (LAM) test in HIV-positive, ART-naïve clinic patients.METHODS: A total of 783 eligible patients were enrolled; three spot sputum samples of 646 patients were tested using TB-LAMP, Xpert, smear microscopy and culture, while 649 patients had TB-LAM testing. Sensitivity, specificity, and negative and positive predictive values were estimated with 95% confidence intervals.RESULTS: Sensitivities for smear microscopy, TB-LAMP and Xpert were respectively 50%, 63% and 74% compared to culture, with specificities of respectively 99.2%, 98.5% and 97.5%. An additional eight were positive on TB-LAM alone. Seventy TB patients (9%) were detected using standard-of-care testing, an additional 27 (3%) were detected using study testing. Treatment was initiated in 57/70 (81%) clinic patients, but only in 56% (57/97) of all those with positive TB tests; 4/8 multidrug-resistant samples were detected using Xpert.CONCLUSION: TB diagnostics continue to miss cases in this high-burden setting. TB-LAMP was more sensitive than smear microscopy, and if followed by culture and drug susceptibility testing as required, can diagnose TB in HIV-positive patients. TB-LAM is a useful add-in test and both tests at the point-of-care would maximise yield.
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Affiliation(s)
- E Spooner
- Department of Paediatrics and Child Health, University of KwaZulu-Natal, Durban, South Africa, HIV Prevention Research Unit, South African Medical Research Council, Durban, South Africa
| | - S Reddy
- South African Medical Research Council, Durban, South Africa
| | - S Ntoyanto
- HIV Prevention Research Unit, South African Medical Research Council, Durban, South Africa
| | - Y Sakadavan
- HIV Prevention Research Unit, South African Medical Research Council, Durban, South Africa
| | - T Reddy
- Biostatistics Unit, South African Medical Research Council, Durban, South Africa
| | - S Mahomed
- School of Laboratory Medicine and Medical Sciences, University of KwaZulu-Natal, Durban, South Africa, Medical Microbiology Department, National Health Laboratory Services, Durban, South Africa, Centre for AIDS Programme Research in South Africa, Durban, South Africa
| | - K Mlisana
- School of Laboratory Medicine and Medical Sciences, University of KwaZulu-Natal, Durban, South Africa, Medical Microbiology Department, National Health Laboratory Services, Durban, South Africa
| | - M Dlamini
- Medical Microbiology Department, National Health Laboratory Services, Durban, South Africa
| | - B Daniels
- HIV Prevention Research Unit, South African Medical Research Council, Durban, South Africa
| | - N Luthuli
- EThekwini Health Unit, EThekwini Municipality, Durban, South Africa
| | - N Ngomane
- Occupational Health, Durban, South Africa
| | - P Kiepiela
- South African Medical Research Council, Durban, South Africa
| | - A Coutsoudis
- Department of Paediatrics and Child Health, University of KwaZulu-Natal, Durban, South Africa
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Reddy S, Ntoyanto S, Sakadavan Y, Reddy T, Mahomed S, Dlamini M, Spooner B, Ramjee G, Coutsoudis A, Ngomane N, Naidoo K, Mlisana K, Kiepiela P. Detecting Mycobacterium tuberculosis using the loop-mediated isothermal amplification test in South Africa. Int J Tuberc Lung Dis 2018; 21:1154-1160. [PMID: 28911361 DOI: 10.5588/ijtld.16.0863] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
Abstract
SETTING In South Africa, KwaZulu-Natal is the epicentre of the human immunodeficiency virus (HIV) epidemic, where approximately 70% of people with tuberculosis (TB) are co-infected with HIV. Undiagnosed TB contributes to high mortality in HIV-infected patients. Delays in diagnosing TB and treatment initiation result in prolonged transmission and increased infectiousness. OBJECTIVE To evaluate the LoopampTM MTBC Detection kit (TB-LAMP; based on the loop-mediated isothermal amplification assay), smear microscopy and Xpert test with the gold standard of mycobacterial culture. METHODS Sputum samples were collected from 705 patients with symptoms of pulmonary TB attending a primary health care clinic. RESULTS The TB-LAMP assay had significantly higher sensitivity than smear microscopy (72.6% vs. 45.4%, P < 0.001), whereas specificity was slightly lower (99% vs. 96.8%, P = 0.05), but significantly higher than Xpert (92.9%, P = 0.004). There was no significant difference in sensitivity of smear-positive, culture-positive and smear-negative, culture-positive sputum samples using TB-LAMP vs. Xpert (respectively 95.9%/55.9% vs. 97.6%/66.1%; P =0.65, P = 0.27). The positive predictive value of TB-LAMP was significantly higher than that of Xpert (87.5% vs. 77.0%; P = 0.02), but similar to that of smear microscopy (94.2%; P = 0.18). The negative predictive value was respectively 91.9%, 92.5% (P = 0.73) and 83.1% (P = 0.0001). CONCLUSION Given its ease of operability, the TB-LAMP assay could be implemented as a point-of-care test in primary health care settings, and contribute to reducing treatment waiting times and TB prevalence.
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Affiliation(s)
- S Reddy
- HIV Prevention Research Unit
| | | | | | - T Reddy
- Biostatistics Unit, South African Medical Research Council, Durban
| | - S Mahomed
- School of Laboratory Medicine and Medical Sciences, University of KwaZulu-Natal, Durban, Medical Microbiology Department, National Health Laboratory Services, Durban, Centre for the AIDS Programme of Research in South Africa, Durban
| | - M Dlamini
- Medical Microbiology Department, National Health Laboratory Services, Durban
| | - B Spooner
- HIV Prevention Research Unit, Department of Paediatrics and Child Health, University of KwaZulu-Natal, Durban
| | | | - A Coutsoudis
- Department of Paediatrics and Child Health, University of KwaZulu-Natal, Durban
| | - N Ngomane
- eThekwini Health Unit, eThekwini Municipality, Durban, South Africa
| | - K Naidoo
- Centre for the AIDS Programme of Research in South Africa, Durban
| | - K Mlisana
- School of Laboratory Medicine and Medical Sciences, University of KwaZulu-Natal, Durban, Medical Microbiology Department, National Health Laboratory Services, Durban
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