Dataset Information

Sensitive electrochemiluminescence (ECL) immunoassays for detecting lipoarabinomannan (LAM) and ESAT-6 in urine and serum from tuberculosis patients.

ABSTRACT: BACKGROUND:Tuberculosis (TB) infection was responsible for an estimated 1.3 million deaths in 2017. Better diagnostic tools are urgently needed. We sought to determine whether accurate TB antigen detection in blood or urine has the potential to meet the WHO target product profiles for detection of active TB. MATERIALS AND METHODS:We developed Electrochemiluminescence (ECL) immunoassays for Lipoarabinomannan (LAM) and ESAT-6 detection with detection limits in the pg/ml range and used them to compare the concentrations of the two antigens in the urine and serum of 81 HIV-negative and -positive individuals with presumptive TB enrolled across diverse geographic sites. RESULTS:LAM and ESAT-6 overall sensitivities in urine were 93% and 65% respectively. LAM and ESAT-6 overall sensitivities in serum were 55% and 46% respectively. Overall specificity was ?97% in all assays. Sensitivities were higher in HIV-positive compared to HIV-negative patients for both antigens and both sample types, with signals roughly 10-fold higher on average in urine than in serum. The two antigens showed similar concentration ranges within the same sample type and correlated. CONCLUSIONS:LAM and ESAT-6 can be detected in the urine and serum of TB patients, regardless of the HIV status and further gains in clinical sensitivity may be achievable through assay and reagent optimization. Accuracy in urine was higher with current methods and has the potential to meet the WHO accuracy target if the findings can be transferred to a point-of-care TB test.

SUBMITTER: Broger T

PROVIDER: S-EPMC6472883 | biostudies-literature | 2019

REPOSITORIES: biostudies-literature

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Sensitive electrochemiluminescence (ECL) immunoassays for detecting lipoarabinomannan (LAM) and ESAT-6 in urine and serum from tuberculosis patients.

Broger Tobias T Tsionksy Michael M Mathew Anu A Lowary Todd L TL Pinter Abraham A Plisova Tatiana T Bartlett Daniel D Barbero Simone S Denkinger Claudia M CM Moreau Emmanuel E Katsuragi Kiyonori K Kawasaki Masanori M Nahid Payam P Sigal George B GB

PloS one 20190418 4

<h4>Background</h4>Tuberculosis (TB) infection was responsible for an estimated 1.3 million deaths in 2017. Better diagnostic tools are urgently needed. We sought to determine whether accurate TB antigen detection in blood or urine has the potential to meet the WHO target product profiles for detection of active TB.<h4>Materials and methods</h4>We developed Electrochemiluminescence (ECL) immunoassays for Lipoarabinomannan (LAM) and ESAT-6 detection with detection limits in the pg/ml range and us ...[more]

PMID: 30998715

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Project description:BackgroundTuberculosis (TB) is a serious co-morbidity among children with severe acute malnutrition (SAM) and TB diagnosis remains particularly challenging in the very young. We explored whether, in a low HIV-prevalence setting, the detection of mycobacterial lipoarabinomannan (LAM) antigen in urine may assist TB diagnosis in SAM children, a pediatric population currently not included in LAM-testing recommendations. To that end, we assessed LAM test-positivity among SAM children with and without signs or symptoms of TB.MethodsA cross-sectional assessment (February 2016-August 2017) included children <5 years with SAM from an Intensive-Therapeutic-Feeding-Centre in Madaoua, Niger. Group 1: children with signs or symptoms suggestive of TB. Group 2: children without any sign or symptom of TB. Urine-specimens were subjected to DetermineTM TB-LAM lateral-flow-test (using a 4-grade intensity scale for positives). LAM-results were used for study purposes and not for patient management. Programmatic TB-diagnosis was primarily based on patients' clinical symptoms and TB contact history with no systematic access to X-ray or microbiological reference testing.Results102 (Group 1) and 100 children (Group 2) were included (median age 18 months, 59.4% male, 1.0% HIV-positive). In Group 1, 22 (21.6%) children were started on TB-treatment (probable TB) and none of the children in Group 2. LAM-positivity was 52.0% (53/102) and 37.0% (37/100) in Group 1 and 2, respectively. Low-intensity (Grade 1) LAM test-positivity was similarly high in both Groups (37.3% and 36.0%, respectively), while Grade 2 or 3-positives were mainly detected in Group 1 (Group 1: 14.7%, Group 2: 1.0%, p<0.001). When considering only Grades >1 as positive, LAM-testing detected 22.7% (95%CI: 7.8, 45.4) among probable TB cases, while 99% (95%CI: 94.6, 99.9) of unlikely TB cases (Group 2) tested negative.ConclusionThese findings suggest the potential utility of LAM urine testing in HIV-negative children with SAM. Determine LAM-positivity with Grades >1 may identify HIV-negative SAM children that are eligible for rapid TB-treatment initiation, though low-intensity (Grade 1) LAM-positive results may not be helpful in this way. Further studies in this specific pediatric population are warranted, including evaluations of new generation LAM tests.

Project description:BackgroundTuberculosis (TB) is a global burden, and this is likely to remain the case due to a lack of adequate and accurate point-of-care diagnostic tests. Obtaining good-quality sputum from the bottom of the respiratory tract of children is challenging. Lipoarabinomannan (LAM) is a specific component of the mycobacterial cell envelope that is excreted in the urine of people with active TB. This study aimed to assess the performance of different types of urine-based LAM antigen tests for the diagnosis of TB in children.MethodsRelevant databases were searched for studies that used urine-based LAM tests to diagnose TB in children. Study quality was assessed using the Joanna Briggs Institute Critical Appraisal Tool. Pooled sensitivity and specificity were calculated using the random-effect model in STATA Version 16.0. Moreover, subgroup analysis was undertaken to hinder the heterogeneity of the studies.ResultsEleven articles were included in the final systematic review and meta-analysis. The pooled sensitivity and specificity of the Mycobacterium tuberculosis enzyme-linked immunosorbent assay (MTB-LAM-ELISA), Alere Determine TB LAM Ag (Alere LAM) test and the Fujifilm SILVAMP TB LAM (Fuji LAM) test in children aged <15 years with TB were 16.0% [95% confidence interval (CI) 10.25-42.25] and 95.61% (95% CI 93.74-97.74); 45.90% (95% CI 40.40-51.40) and 80.42% (95% CI 69.39-91.46); and 52.32% (95% CI 35.03-69.62) and 89.37% (95% CI 82.88-95.86), respectively. Subgroup analysis revealed that the pooled sensitivity and specificity of MTB-LAM-ELISA, Alere LAM test and Fuji LAM test were 33.5% (95% CI 34.86-100) and 95.83% (95% CI 91.50-100); 46.59% (95% CI 32.98-60.19) and 76.45% (95% CI 57.07-95.82); and 57.89% (95% CI 48.44-67.35%) and 87.66% (95% CI 75.29-100), respectively, in human immunodeficiency virus (HIV)-positive children; and 3.35% (95% CI 1.61-8.31) and 96.0% (95% CI 93.88-98.11); 32.33% (95% CI 7.63-57.03) and 79.07% (95% CI 62.62-95.51); and 50.95% (95% CI 27.45-74.45) and 89.47% (95% CI 84.72-94.22), respectively, in HIV-negative children.ConclusionThe Fuji LAM and Alere LAM tests may be useful for the diagnosis of TB in children in conjunction with other more sensitive and specific tests, although a prospective study in relevant clinical settings is needed to evaluate this. There is a need for more evidence-based data on the use of these rapid diagnostic tools to diagnose TB in children independent of HIV status.

Project description:BACKGROUNDInadequate tuberculosis (TB) diagnostics are a major hurdle in the reduction of disease burden, and accurate point-of-care tests (POCTs) are urgently needed. We assessed the diagnostic accuracy of Fujifilm SILVAMP TB lipoarabinomannan (FujiLAM) POCT for TB diagnosis in HIV-negative outpatients and compared it with Alere Determine TB LAM Ag (AlereLAM) POCT and a laboratory-based ultrasensitive electrochemiluminescence LAM research assay (EclLAM).METHODSIn this multicenter diagnostic test accuracy study, we recruited HIV-negative adults with symptoms suggestive of pulmonary TB presenting to outpatient health care centers in Peru and South Africa. Urine samples were tested using FujiLAM, AlereLAM, and EclLAM, and the diagnostic accuracy was assessed against a microbiological reference standard (MRS) and a composite reference standard.RESULTSThree hundred seventy-two HIV-negative participants were included and the prevalence of microbiologically confirmed TB was 30%. Compared with the MRS, the sensitivities of AlereLAM, FujiLAM, and EclLAM were 10.8% (95% confidence interval [CI] 6.3%-18.0%), 53.2% (95% CI 43.9%-62.1%), and 66.7% (95% CI 57.5%-74.7%), respectively. The specificities of AlereLAM, FujiLAM, and EclLAM were 92.3% (95% CI 88.5%-95.0%), 98.9% (95% CI 96.7%-99.6%), and 98.1% (95% CI 95.6%-99.2%), respectively. Positive likelihood ratios of AlereLAM, FujiLAM, and EclLAM were 1.4, 46.2, and 34.8, respectively, and positive predictive values were 37.5%, 95.2%, and 93.7%, respectively.CONCLUSIONCompared with AlereLAM, FujiLAM detected 5 times more patients with TB in HIV-negative participants, had a high positive predictive value, and has the potential to improve rapid diagnosis of TB at the point-of-care. EclLAM demonstrated that additional sensitivity gains are possible, which highlights LAM's potential as a biomarker. Additional research is required to assess FujiLAM's performance in prospective cohorts, its cost-effectiveness, and its impact in real-world clinical settings.FUNDINGGlobal Health Innovative Technology Fund, the UK Department for International Development, the Dutch Ministry of Foreign Affairs, the Bill and Melinda Gates Foundation, the Australian Department of Foreign Affairs and Trade, the German Federal Ministry of Education and Research through Kreditanstalt für Wiederaufbau, and the NIH and National Institute of Allergy and Infectious Diseases.

Project description:The Fujifilm SILVAMP TB LAM (FujiLAM) assay offers improved sensitivity compared to Determine TB LAM Ag (AlereLAM) for detecting tuberculosis (TB) among people with HIV. Here, we examined the diagnostic value of FujiLAM testing on early morning urine versus spot urine and the added value of a two-sample strategy. We assessed the diagnostic accuracy of FujiLAM on cryopreserved urine samples collected and stored as part of a prospective cohort of adults with HIV presenting for antiretroviral treatment in Ghana. We compared FujiLAM sensitivity and specificity in spontaneously voided urine samples collected at inclusion (spot urine) versus in the first voided early morning urine (morning urine) and for a one (spot urine) versus two samples (spot and morning urine) strategy. Diagnostic accuracy was determined against both microbiological (using sputum culture and Xpert MTB/RIF testing of sputum and urine to confirm TB) and composite reference standards (including microbiologically confirmed and probable TB cases). Paired urine samples of spot and morning urine were available for 389 patients. Patients had a median CD4 cell count of 176 cells/μL (interquartile range [IQR], 52 to 361). Forty-three (11.0%) had confirmed TB, and 19 (4.9%) had probable TB. Overall agreement for spot versus morning urine test results was 94.6% (kappa, 0.81). Compared to a microbiological reference standard, the FujiLAM sensitivity (95% confidence interval [CI]) was 67.4% (51.5 to 80.9) for spot and 69.8% (53.9 to 82.8) for morning urine, an absolute difference (95% CI) of 2.4% (-10.2 to 14.8). Specificity was 90.2% (86.5 to 93.1) versus 89.0% (85.2 to 92.1) for spot and morning urine, respectively, a difference of 1.2% (-3.7 to 1.4). A two-sample strategy increased FujiLAM sensitivity from 67.4% (51.5 to 80.9) to 74.4% (58.8 to 86.5), a difference of 7.0% (-3.0 to 16.9), while specificity decreased from 90.2% (86.5 to 93.1) to 87.3% (83.3 to 90.6), a difference of -2.9% (-4.9 to -0.8). This study indicates that FujiLAM testing performs equivalently on spot and early morning urine samples. Sensitivity could be increased with a two-sample strategy but at the risk of lower specificity. These data can inform future guidelines and clinical practice. IMPORTANCE This study indicates that FujiLAM testing performs equivalently on spot and early morning urine samples for detecting tuberculosis among people with HIV. Sensitivity could be increased with a two-sample strategy but at the risk of lower specificity. These data can inform future guidelines and clinical practice around FujiLAM.

Dataset Information

Sensitive electrochemiluminescence (ECL) immunoassays for detecting lipoarabinomannan (LAM) and ESAT-6 in urine and serum from tuberculosis patients.

Publications

Sensitive electrochemiluminescence (ECL) immunoassays for detecting lipoarabinomannan (LAM) and ESAT-6 in urine and serum from tuberculosis patients.

Similar Datasets

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