Journal Article > LetterFull Text
Lancet Global Health. 2023 April 1; Volume 11 (Issue 4); e502.; DOI:10.1016/S2214-109X(23)00115-8
Huerga H, Gupta-Wright A, Muyindike WR, Hewison CCH, Casenghi M, et al.
Lancet Global Health. 2023 April 1; Volume 11 (Issue 4); e502.; DOI:10.1016/S2214-109X(23)00115-8
Journal Article > ResearchFull Text
PLOS One. 2015 December 15; Volume 10 (Issue 12); e0144656.; DOI:10.1371/journal.pone.0144656
Ardizzoni E, Fajardo E, Saranchuk P, Casenghi M, Page AL, et al.
PLOS One. 2015 December 15; Volume 10 (Issue 12); e0144656.; DOI:10.1371/journal.pone.0144656
BACKGROUND
The Xpert® MTB/RIF (Xpert) is an automated molecular test for simultaneous detection of tuberculosis (TB) and rifampicin resistance, recommended by the World Health Organization as the preferred diagnostic method for individuals presumed to have multi-drug resistant TB (MDR-TB) or HIV-associated TB. We describe the performance of Xpert and key lessons learned during two years of implementation under routine conditions in 33 projects located in 18 countries supported by Médecins Sans Frontières across varied geographic, epidemiological and clinical settings.
METHODS
Xpert was used following three strategies: the first being as the initial test, with microscopy in parallel, for all presumptive TB cases; the second being only for patients at risk of MDR-TB, or with HIV- associated TB, or presumptive paediatric TB; and the third being as the initial test for these high-risk patients plus as an add-on test to microscopy in others. Routine laboratory data were collected, using laboratory registers. Qualitative data such as logistic aspects, human resources, and tool acceptance were collected using a questionnaire.
FINDINGS
In total, 52,863 samples underwent Xpert testing from April 2011 to December 2012. The average MTB detection rate was 18.5%, 22.3%, and 11.6% for the three different strategies respectively. Analysis of the results on samples tested in parallel showed that using Xpert as add-on test to microscopy would have increased laboratory TB confirmation by 49.7%, versus 42.3% for Xpert replacing microscopy. The main limitation of the test was the high rate of inconclusive results, which correlated with factors such as defective modules, cartridge version (G3 vs. G4) and staff experience. Operational and logistical hurdles included infrastructure renovation, basic computer training, regular instrument troubleshooting and maintenance, all of which required substantial and continuous support.
CONCLUSION
The implementation of Xpert was feasible and significantly increased TB detection compared to microscopy, despite the high rate of inconclusive results. Xpert implementation was accompanied by considerable operational and logistical challenges. To further decentralize diagnosis, simpler, low-cost TB technologies well-suited to low-resource settings are still urgently needed.
The Xpert® MTB/RIF (Xpert) is an automated molecular test for simultaneous detection of tuberculosis (TB) and rifampicin resistance, recommended by the World Health Organization as the preferred diagnostic method for individuals presumed to have multi-drug resistant TB (MDR-TB) or HIV-associated TB. We describe the performance of Xpert and key lessons learned during two years of implementation under routine conditions in 33 projects located in 18 countries supported by Médecins Sans Frontières across varied geographic, epidemiological and clinical settings.
METHODS
Xpert was used following three strategies: the first being as the initial test, with microscopy in parallel, for all presumptive TB cases; the second being only for patients at risk of MDR-TB, or with HIV- associated TB, or presumptive paediatric TB; and the third being as the initial test for these high-risk patients plus as an add-on test to microscopy in others. Routine laboratory data were collected, using laboratory registers. Qualitative data such as logistic aspects, human resources, and tool acceptance were collected using a questionnaire.
FINDINGS
In total, 52,863 samples underwent Xpert testing from April 2011 to December 2012. The average MTB detection rate was 18.5%, 22.3%, and 11.6% for the three different strategies respectively. Analysis of the results on samples tested in parallel showed that using Xpert as add-on test to microscopy would have increased laboratory TB confirmation by 49.7%, versus 42.3% for Xpert replacing microscopy. The main limitation of the test was the high rate of inconclusive results, which correlated with factors such as defective modules, cartridge version (G3 vs. G4) and staff experience. Operational and logistical hurdles included infrastructure renovation, basic computer training, regular instrument troubleshooting and maintenance, all of which required substantial and continuous support.
CONCLUSION
The implementation of Xpert was feasible and significantly increased TB detection compared to microscopy, despite the high rate of inconclusive results. Xpert implementation was accompanied by considerable operational and logistical challenges. To further decentralize diagnosis, simpler, low-cost TB technologies well-suited to low-resource settings are still urgently needed.
Journal Article > ResearchFull Text
J Acquir Immune Defic Syndr; JAIDS. 2024 April 15; Volume 95 (Issue 5); 431-438.; DOI:10.1097/QAI.0000000000003379
Youngui BT, Atwine D, Otai D, Vasiliu A, Ssekyanzi B, et al.
J Acquir Immune Defic Syndr; JAIDS. 2024 April 15; Volume 95 (Issue 5); 431-438.; DOI:10.1097/QAI.0000000000003379
INTRODUCTION
People living with HIV are considered at higher risk of developing severe forms of tuberculosis (TB) disease. Providing HIV testing to TB-exposed people is therefore critical. We present the results of integrating HIV testing into a community-based intervention for household TB contact management in Cameroon and Uganda.
METHODS
Trained community health workers visited the households of index patients with TB identified in 3 urban/semiurban and 6 rural districts or subdistricts as part of a cluster-randomized trial and provided TB screening to all household contacts. Voluntary HIV counseling and testing were offered to contacts aged 5 years or older with unknown HIV status. We describe the cascade of care for HIV testing and the factors associated with the acceptance of HIV testing.
RESULTS
Overall, 1983 household contacts aged 5 years or older were screened for TB. Of these contacts, 1652 (83.3%) did not know their HIV status, 1457 (88.2%) accepted HIV testing, and 1439 (98.8%) received testing. HIV testing acceptance was lower among adults than children [adjusted odds ratio (aOR) = 0.35, 95% confidence interval (CI): 0.22 to 0.55], those living in household of an HIV-positive vs HIV-negative index case (aOR = 0.56, 95% CI: 0.38 to 0.83), and contacts requiring a reassessment visit after the initial TB screening visit vs asymptomatic contacts (aOR = 0.20, 95% CI: 0.06 to 0.67) and was higher if living in Uganda vs Cameroon (aOR = 4.54, 95% CI: 1.17 to 17.62) or if another contact of the same index case was tested for HIV (aOR = 9.22, 95% CI: 5.25 to 16.18).
CONCLUSION
HIV testing can be integrated into community-based household TB contact screening and is well-accepted.
People living with HIV are considered at higher risk of developing severe forms of tuberculosis (TB) disease. Providing HIV testing to TB-exposed people is therefore critical. We present the results of integrating HIV testing into a community-based intervention for household TB contact management in Cameroon and Uganda.
METHODS
Trained community health workers visited the households of index patients with TB identified in 3 urban/semiurban and 6 rural districts or subdistricts as part of a cluster-randomized trial and provided TB screening to all household contacts. Voluntary HIV counseling and testing were offered to contacts aged 5 years or older with unknown HIV status. We describe the cascade of care for HIV testing and the factors associated with the acceptance of HIV testing.
RESULTS
Overall, 1983 household contacts aged 5 years or older were screened for TB. Of these contacts, 1652 (83.3%) did not know their HIV status, 1457 (88.2%) accepted HIV testing, and 1439 (98.8%) received testing. HIV testing acceptance was lower among adults than children [adjusted odds ratio (aOR) = 0.35, 95% confidence interval (CI): 0.22 to 0.55], those living in household of an HIV-positive vs HIV-negative index case (aOR = 0.56, 95% CI: 0.38 to 0.83), and contacts requiring a reassessment visit after the initial TB screening visit vs asymptomatic contacts (aOR = 0.20, 95% CI: 0.06 to 0.67) and was higher if living in Uganda vs Cameroon (aOR = 4.54, 95% CI: 1.17 to 17.62) or if another contact of the same index case was tested for HIV (aOR = 9.22, 95% CI: 5.25 to 16.18).
CONCLUSION
HIV testing can be integrated into community-based household TB contact screening and is well-accepted.
Journal Article > CommentaryFull Text
Lancet Child Adolesc Health. 2023 September 11; Volume 7 (Issue 10); 675-677.; DOI:10.1016/S2352-4642(23)00217-1
Deborggraeve S, Casenghi M, Hewison CCH, Ditekemena J, Ditiu L, et al.
Lancet Child Adolesc Health. 2023 September 11; Volume 7 (Issue 10); 675-677.; DOI:10.1016/S2352-4642(23)00217-1
Journal Article > CommentaryFull Text
J Int AIDS Soc. 2010 January 1; Volume 13 (Issue 1); 40-40.; DOI:10.1186/1758-2652-13-40
Lemaire J-F, Casenghi M
J Int AIDS Soc. 2010 January 1; Volume 13 (Issue 1); 40-40.; DOI:10.1186/1758-2652-13-40
BACKGROUND
An effective tuberculosis (TB) control programme requires early diagnosis and immediate initiation of treatment. Any delays in diagnosing TB not only impair a patient's prognosis, but also increase the risks of transmitting the disease within the community. Unfortunately, the most recent TB diagnostic tools still depend on high-infrastructure laboratories, making them poorly adapted for use in resource-limited settings. Additionally, existing tests show poor performance in diagnosing TB in children, people living with HIV/AIDS, and extrapulmonary forms of the disease. As a consequence, TB patients are still to date left with either fair access to poor diagnostics or poor access to fair diagnostics.
DISCUSSION
This article discusses recent efforts to identify the minimal test specifications for a new TB point-of-care diagnostic test through an approach based on medical and patient needs. As a first step, survey interviews with field practitioners were designed in order to identify the top-priority medical needs in resource-limited settings concerning new TB diagnostics. Subsequently, an expert meeting convening field practitioners, laboratory experts, diagnostic test developers and researchers was held with the objective of defining the minimal test specifications for a new TB point-of-care test that would meet the identified medical needs. Finally, gaps in, as well as potential solutions for, enabling the development of adequate, patient needs-driven, low-cost new TB diagnostic tests specifically designed for vulnerable populations are discussed.
SUMMARY
Any new TB point-of-care diagnostic test should be designed to meet minimal specifications satisfying the most urgent medical needs in resource-poor settings. The major gaps for developing a new TB point-of-care test include identification of new biomarkers, simplification of technological platforms, development of adequate and accessible specimen banks, and identification and definition of reference standards for diagnosis of childhood TB. Innovative research and development funding ensuring de-linkage of research and development costs from the price of the new product, such as a prize fund mechanism, could help focus these efforts towards the delivery of a much-needed point-of-care diagnostic test for TB.
An effective tuberculosis (TB) control programme requires early diagnosis and immediate initiation of treatment. Any delays in diagnosing TB not only impair a patient's prognosis, but also increase the risks of transmitting the disease within the community. Unfortunately, the most recent TB diagnostic tools still depend on high-infrastructure laboratories, making them poorly adapted for use in resource-limited settings. Additionally, existing tests show poor performance in diagnosing TB in children, people living with HIV/AIDS, and extrapulmonary forms of the disease. As a consequence, TB patients are still to date left with either fair access to poor diagnostics or poor access to fair diagnostics.
DISCUSSION
This article discusses recent efforts to identify the minimal test specifications for a new TB point-of-care diagnostic test through an approach based on medical and patient needs. As a first step, survey interviews with field practitioners were designed in order to identify the top-priority medical needs in resource-limited settings concerning new TB diagnostics. Subsequently, an expert meeting convening field practitioners, laboratory experts, diagnostic test developers and researchers was held with the objective of defining the minimal test specifications for a new TB point-of-care test that would meet the identified medical needs. Finally, gaps in, as well as potential solutions for, enabling the development of adequate, patient needs-driven, low-cost new TB diagnostic tests specifically designed for vulnerable populations are discussed.
SUMMARY
Any new TB point-of-care diagnostic test should be designed to meet minimal specifications satisfying the most urgent medical needs in resource-poor settings. The major gaps for developing a new TB point-of-care test include identification of new biomarkers, simplification of technological platforms, development of adequate and accessible specimen banks, and identification and definition of reference standards for diagnosis of childhood TB. Innovative research and development funding ensuring de-linkage of research and development costs from the price of the new product, such as a prize fund mechanism, could help focus these efforts towards the delivery of a much-needed point-of-care diagnostic test for TB.
Journal Article > ResearchFull Text
Lancet Global Health. 2023 October 30; Online ahead of print; S2214-109X(23)00430-8.; DOI:10.1016/S2214-109X(23)00430-8
Bonnet MMB, Vasiliu A, Tchounga BK, Cuer B, Fielding K, et al.
Lancet Global Health. 2023 October 30; Online ahead of print; S2214-109X(23)00430-8.; DOI:10.1016/S2214-109X(23)00430-8
BACKGROUND
Globally, the uptake of tuberculosis-preventive treatment (TPT) among children with household tuberculosis contact remains low, partly due to the necessity of bringing children to health facilities for investigations. This study aimed to evaluate the effect on TPT initiation and completion of community-based approaches to tuberculosis contact investigations in Cameroon and Uganda.
METHODS
We did a parallel, cluster-randomised, controlled trial across 20 clusters (consisting of 25 district hospitals and primary health centres) in Cameroon and Uganda, which were randomised (1:1) to receive a community-based approach (intervention group) or standard-of-care facility-based approach to contact screening and management (control group). The community-based approach consisted of symptom-based tuberculosis screening of all household contacts by community health workers at the household, with referral of symptomatic contacts to local facilities for investigations. Initiation of TPT (3-month course of rifampicin-isoniazid) was done by a nurse in the household, and home visits for TPT follow-up were done by community health workers. Index patients were people aged 15 years or older with bacteriologically confirmed, drug-susceptible, pulmonary tuberculosis diagnosed less than 1 month before inclusion and who declared at least one child or young adolescent (aged 0-14 years) household contact. The primary endpoint was the proportion of declared child contacts in the TPT target group (those aged <5 years irrespective of HIV status, and children aged 5-14 years living with HIV) who commenced and completed TPT, assessed in the modified intention-to-treat population (excluding enrolled index patients and their contacts who did not fit the eligibility criteria). Descriptive cascade of care assessment and generalised linear mixed modelling were used for comparison. This study is registered with ClinicalTrials.gov (NCT03832023).
FINDINGS
The study included nine clusters in the intervention group (after excluding one cluster that did not enrol any index patients for >2 months) and ten in the control group. Between Oct 14, 2019 and Jan 13, 2022, 2894 child contacts were declared by 899 index patients with bacteriologically confirmed tuberculosis. Among all child contacts declared, 1548 (81·9%) of 1889 in the intervention group and 475 (47·3%) of 1005 in the control group were screened for tuberculosis. 1400 (48·4%) child contacts were considered to be in the TPT target group: 941 (49·8%) of 1889 in the intervention group and 459 (45·7%) of 1005 in the control group. In the TPT target group, TPT was commenced and completed in 752 (79·9%) of 941 child contacts in the intervention group and 283 (61·7%) of 459 in the control group (odds ratio 3·06 [95% CI 1·24-7·53]).
INTERPRETATION
A community-based approach using community health workers can significantly increase contact investigation coverage and TPT completion among eligible child contacts in a tuberculosis-endemic setting.
Globally, the uptake of tuberculosis-preventive treatment (TPT) among children with household tuberculosis contact remains low, partly due to the necessity of bringing children to health facilities for investigations. This study aimed to evaluate the effect on TPT initiation and completion of community-based approaches to tuberculosis contact investigations in Cameroon and Uganda.
METHODS
We did a parallel, cluster-randomised, controlled trial across 20 clusters (consisting of 25 district hospitals and primary health centres) in Cameroon and Uganda, which were randomised (1:1) to receive a community-based approach (intervention group) or standard-of-care facility-based approach to contact screening and management (control group). The community-based approach consisted of symptom-based tuberculosis screening of all household contacts by community health workers at the household, with referral of symptomatic contacts to local facilities for investigations. Initiation of TPT (3-month course of rifampicin-isoniazid) was done by a nurse in the household, and home visits for TPT follow-up were done by community health workers. Index patients were people aged 15 years or older with bacteriologically confirmed, drug-susceptible, pulmonary tuberculosis diagnosed less than 1 month before inclusion and who declared at least one child or young adolescent (aged 0-14 years) household contact. The primary endpoint was the proportion of declared child contacts in the TPT target group (those aged <5 years irrespective of HIV status, and children aged 5-14 years living with HIV) who commenced and completed TPT, assessed in the modified intention-to-treat population (excluding enrolled index patients and their contacts who did not fit the eligibility criteria). Descriptive cascade of care assessment and generalised linear mixed modelling were used for comparison. This study is registered with ClinicalTrials.gov (NCT03832023).
FINDINGS
The study included nine clusters in the intervention group (after excluding one cluster that did not enrol any index patients for >2 months) and ten in the control group. Between Oct 14, 2019 and Jan 13, 2022, 2894 child contacts were declared by 899 index patients with bacteriologically confirmed tuberculosis. Among all child contacts declared, 1548 (81·9%) of 1889 in the intervention group and 475 (47·3%) of 1005 in the control group were screened for tuberculosis. 1400 (48·4%) child contacts were considered to be in the TPT target group: 941 (49·8%) of 1889 in the intervention group and 459 (45·7%) of 1005 in the control group. In the TPT target group, TPT was commenced and completed in 752 (79·9%) of 941 child contacts in the intervention group and 283 (61·7%) of 459 in the control group (odds ratio 3·06 [95% CI 1·24-7·53]).
INTERPRETATION
A community-based approach using community health workers can significantly increase contact investigation coverage and TPT completion among eligible child contacts in a tuberculosis-endemic setting.
Journal Article > ResearchFull Text
Lancet Global Health. 2023 October 30; Online ahead of print (Issue 23); S2214-109X(23)00451-5.; DOI:10.1016/S2214-109X(23)00451-5
Mafirakureva N, Tchounga BK, Mukherjee S, Youngui BT, Ssekyanzi B, et al.
Lancet Global Health. 2023 October 30; Online ahead of print (Issue 23); S2214-109X(23)00451-5.; DOI:10.1016/S2214-109X(23)00451-5
BACKGROUND
WHO recommends household contact management (HCM) including contact screening and tuberculosis-preventive treatment (TPT) for eligible children. The CONTACT trial found increased TPT initiation and completion rates when community health workers were used for HCM in Cameroon and Uganda.
METHODS
We did a cost-utility analysis of the CONTACT trial using a health-system perspective to estimate the health impact, health-system costs, and cost-effectiveness of community-based versus facility-based HCM models of care. A decision-analytical modelling approach was used to evaluate the cost-effectiveness of the intervention compared with the standard of care using trial data on cascade of care, intervention effects, and resource use. Health outcomes were based on modelled progression to tuberculosis, mortality, and discounted disability-adjusted life-years (DALYs) averted. Health-care resource use, outcomes, costs (2021 US$), and cost-effectiveness are presented.
FINDINGS
For every 1000 index patients diagnosed with tuberculosis, the intervention increased the number of TPT courses by 1110 (95% uncertainty interval 894 to 1227) in Cameroon and by 1078 (796 to 1220) in Uganda compared with the control model. The intervention prevented 15 (-3 to 49) tuberculosis deaths in Cameroon and 10 (-20 to 33) in Uganda. The incremental cost-effectiveness ratio was $620 per DALY averted in Cameroon and $970 per DALY averted in Uganda.
INTERPRETATION
Community-based HCM approaches can substantially reduce child tuberculosis deaths and in our case would be considered cost-effective at willingness-to-pay thresholds of $1000 per DALY averted. Their impact and cost-effectiveness are likely to be greatest where baseline HCM coverage is lowest.
WHO recommends household contact management (HCM) including contact screening and tuberculosis-preventive treatment (TPT) for eligible children. The CONTACT trial found increased TPT initiation and completion rates when community health workers were used for HCM in Cameroon and Uganda.
METHODS
We did a cost-utility analysis of the CONTACT trial using a health-system perspective to estimate the health impact, health-system costs, and cost-effectiveness of community-based versus facility-based HCM models of care. A decision-analytical modelling approach was used to evaluate the cost-effectiveness of the intervention compared with the standard of care using trial data on cascade of care, intervention effects, and resource use. Health outcomes were based on modelled progression to tuberculosis, mortality, and discounted disability-adjusted life-years (DALYs) averted. Health-care resource use, outcomes, costs (2021 US$), and cost-effectiveness are presented.
FINDINGS
For every 1000 index patients diagnosed with tuberculosis, the intervention increased the number of TPT courses by 1110 (95% uncertainty interval 894 to 1227) in Cameroon and by 1078 (796 to 1220) in Uganda compared with the control model. The intervention prevented 15 (-3 to 49) tuberculosis deaths in Cameroon and 10 (-20 to 33) in Uganda. The incremental cost-effectiveness ratio was $620 per DALY averted in Cameroon and $970 per DALY averted in Uganda.
INTERPRETATION
Community-based HCM approaches can substantially reduce child tuberculosis deaths and in our case would be considered cost-effective at willingness-to-pay thresholds of $1000 per DALY averted. Their impact and cost-effectiveness are likely to be greatest where baseline HCM coverage is lowest.
Journal Article > ReviewAbstract
J Infect Dis. 2012 April 10; Volume 205 (Issue suppl_2); DOI:10.1093/infdis/jir860
McNerney R, Maeurer M, Abubakar I, Marais BJ, McHugh TD, et al.
J Infect Dis. 2012 April 10; Volume 205 (Issue suppl_2); DOI:10.1093/infdis/jir860
Tuberculosis is unique among the major infectious diseases in that it lacks accurate rapid point-of-care diagnostic tests. Failure to control the spread of tuberculosis is largely due to our inability to detect and treat all infectious cases of pulmonary tuberculosis in a timely fashion, allowing continued Mycobacterium tuberculosis transmission within communities. Currently recommended gold-standard diagnostic tests for tuberculosis are laboratory based, and multiple investigations may be necessary over a period of weeks or months before a diagnosis is made. Several new diagnostic tests have recently become available for detecting active tuberculosis disease, screening for latent M. tuberculosis infection, and identifying drug-resistant strains of M. tuberculosis. However, progress toward a robust point-of-care test has been limited, and novel biomarker discovery remains challenging. In the absence of effective prevention strategies, high rates of early case detection and subsequent cure are required for global tuberculosis control. Early case detection is dependent on test accuracy, accessibility, cost, and complexity, but also depends on the political will and funder investment to deliver optimal, sustainable care to those worst affected by the tuberculosis and human immunodeficiency virus epidemics. This review highlights unanswered questions, challenges, recent advances, unresolved operational and technical issues, needs, and opportunities related to tuberculosis diagnostics.
Journal Article > ResearchFull Text
PLOS Med. 2007 November 6; Volume 4 (Issue 11); DOI:10.1371/journal.pmed.0040293
Casenghi M, Cole ST, Nathan CF
PLOS Med. 2007 November 6; Volume 4 (Issue 11); DOI:10.1371/journal.pmed.0040293
Journal Article > ResearchFull Text
Lancet Global Health. 2023 January 1; Volume 11 (Issue 1); e126-e135.; DOI:10.1016/S2214-109X(22)00463-6
Huerga H, Bastard M, Lubega AV, Akinyi M, Antabak NT, et al.
Lancet Global Health. 2023 January 1; Volume 11 (Issue 1); e126-e135.; DOI:10.1016/S2214-109X(22)00463-6
BACKGROUND
Development of rapid biomarker-based tests that can diagnose tuberculosis using non-sputum samples is a priority for tuberculosis control. We aimed to compare the diagnostic accuracy of the novel Fujifilm SILVAMP TB LAM (FujiLAM) assay with the WHO-recommended Alere Determine TB-LAM Ag test (AlereLAM) using urine samples from HIV-positive patients.
METHODS
We did a diagnostic accuracy study at five outpatient public health facilities in Uganda, Kenya, Mozambique, and South Africa. Eligible patients were ambulatory HIV-positive individuals (aged ≥15 years) with symptoms of tuberculosis irrespective of their CD4 T-cell count (group 1), and asymptomatic patients with advanced HIV disease (CD4 count <200 cells per μL, or HIV clinical stage 3 or 4; group 2). All participants underwent clinical examination, chest x-ray, and blood sampling, and were requested to provide a fresh urine sample, and two sputum samples. FujiLAM and AlereLAM urine assays, Xpert MTB/RIF Ultra assay on sputum or urine, sputum culture for Mycobacterium tuberculosis, and CD4 count were systematically carried out for all patients. Sensitivity and specificity of FujiLAM and AlereLAM were evaluated against microbiological and composite reference standards.
FINDINGS
Between Aug 24, 2020 and Sept 21, 2021, 1575 patients (823 [52·3%] women) were included in the study: 1031 patients in group 1 and 544 patients in group 2. Tuberculosis was microbiologically confirmed in 96 (9·4%) of 1022 patients in group 1 and 18 (3·3%) of 542 patients in group 2. Using the microbiological reference standard, FujiLAM sensitivity was 60% (95% CI 51–69) and AlereLAM sensitivity was 40% (31–49; p<0·001). Among patients with CD4 counts of less than 200 cells per μL, FujiLAM sensitivity was 69% (57–79) and AlereLAM sensitivity was 52% (40–64; p=0·0218). Among patients with CD4 counts of 200 cells per μL or higher, FujiLAM sensitivity was 47% (34–61) and AlereLAM sensitivity was 24% (14–38; p=0·0116). Using the microbiological reference standard, FujiLAM specificity was 87% (95% CI 85–89) and AlereLAM specificity was 86% (95 CI 84–88; p=0·941). FujiLAM sensitivity varied by lot number from 48% (34–62) to 76% (57–89) and specificity from 77% (72–81) to 98% (93–99).
INTERPRETATION
Next-generation, higher sensitivity urine-lipoarabinomannan assays are potentially promising tests that allow rapid tuberculosis diagnosis at the point of care for HIV-positive patients. However, the variability in accuracy between FujiLAM lot numbers needs to be addressed before clinical use.
Development of rapid biomarker-based tests that can diagnose tuberculosis using non-sputum samples is a priority for tuberculosis control. We aimed to compare the diagnostic accuracy of the novel Fujifilm SILVAMP TB LAM (FujiLAM) assay with the WHO-recommended Alere Determine TB-LAM Ag test (AlereLAM) using urine samples from HIV-positive patients.
METHODS
We did a diagnostic accuracy study at five outpatient public health facilities in Uganda, Kenya, Mozambique, and South Africa. Eligible patients were ambulatory HIV-positive individuals (aged ≥15 years) with symptoms of tuberculosis irrespective of their CD4 T-cell count (group 1), and asymptomatic patients with advanced HIV disease (CD4 count <200 cells per μL, or HIV clinical stage 3 or 4; group 2). All participants underwent clinical examination, chest x-ray, and blood sampling, and were requested to provide a fresh urine sample, and two sputum samples. FujiLAM and AlereLAM urine assays, Xpert MTB/RIF Ultra assay on sputum or urine, sputum culture for Mycobacterium tuberculosis, and CD4 count were systematically carried out for all patients. Sensitivity and specificity of FujiLAM and AlereLAM were evaluated against microbiological and composite reference standards.
FINDINGS
Between Aug 24, 2020 and Sept 21, 2021, 1575 patients (823 [52·3%] women) were included in the study: 1031 patients in group 1 and 544 patients in group 2. Tuberculosis was microbiologically confirmed in 96 (9·4%) of 1022 patients in group 1 and 18 (3·3%) of 542 patients in group 2. Using the microbiological reference standard, FujiLAM sensitivity was 60% (95% CI 51–69) and AlereLAM sensitivity was 40% (31–49; p<0·001). Among patients with CD4 counts of less than 200 cells per μL, FujiLAM sensitivity was 69% (57–79) and AlereLAM sensitivity was 52% (40–64; p=0·0218). Among patients with CD4 counts of 200 cells per μL or higher, FujiLAM sensitivity was 47% (34–61) and AlereLAM sensitivity was 24% (14–38; p=0·0116). Using the microbiological reference standard, FujiLAM specificity was 87% (95% CI 85–89) and AlereLAM specificity was 86% (95 CI 84–88; p=0·941). FujiLAM sensitivity varied by lot number from 48% (34–62) to 76% (57–89) and specificity from 77% (72–81) to 98% (93–99).
INTERPRETATION
Next-generation, higher sensitivity urine-lipoarabinomannan assays are potentially promising tests that allow rapid tuberculosis diagnosis at the point of care for HIV-positive patients. However, the variability in accuracy between FujiLAM lot numbers needs to be addressed before clinical use.