Lipoarabinomannan Antigen Research Articles

Cost-effective chemiresistive biosensor with MWCNT-ZnO nanofibers for early detection of tuberculosis (TB) lipoarabinomannan (LAM) antigen.

Thedevelopment of an affordable chemiresistive biosensor enhanced with a multi-walled carbon nanotube-zinc oxide (MWCNT-ZnO) nanofiber compositeis presented. The sensor leverages the precise interaction between lipoarabinomannan (LAM) tuberculosis (TB) antigens and antibodies to achieve high sensitivity and specificity. The MWCNT-ZnO nanofibers have a larger surface area and better electrical conductivity, which makes it easier for TB antibodies to stick to them. The binding of LAM TB antigens to the fixed Monoclonal Antibody-MBS320597 induces significant resistance changes in the chemiresistive sensor, enabling accurate TB detection. Performance evaluation reveals a linear detection range from 1.0 to 100.0pg/mL in the lower concentration range and up to 6.0ng/mL in the higher concentration range, with a sensitivity of 79.750mApgmL-1cm-2 and a lower limit of detection of 40.54fg/mL. The sensor exhibits a response time of 102s. Featuring rapid response time and high sensitivity, this biosensor is ideally suited for point-of-care (PoC) applications. The incorporation of MWCNT-ZnO nanofibers shows great potential for enhancing the development of sensitive and cost-effective TB diagnostic tools, which could play a crucial role in advancing global TB control and management efforts.

Enhanced tuberculosis diagnosis with computer-aided chest X-ray and urine LAM in adults with HIV admitted to hospital (CASTLE study): A cluster randomised trial.

People with HIV (PHIV) admitted to hospital have high mortality, with tuberculosis (TB) being the major cause of death. Systematic use of new TB diagnostics could improve TB diagnosis and might improve outcomes. We conducted a cluster randomised trial among adult PHIV admitted to Zomba Central Hospital, Malawi. Admission-days were randomly assigned to: enhanced TB diagnostics using urine lipoarabinomannan (LAM) antigen tests (SILVAMP-LAM, Fujifilm, Japan and Determine-LAM, Alere/Abbot, USA), digital chest X-ray with computer aided diagnosis (dCXR-CAD, CAD4TBv6, Delft, Netherlands), plus usual care ("enhanced TB diagnostics"); or usual care alone ("usual care"). The primary outcome was TB treatment initiation during admission. Secondary outcomes were 56-day mortality, TB diagnosis within 24-hours, and undiagnosed TB at discharge, ascertained by culture of one admission sputum sample. Between 2 September 2020 and 15 February 2022, we recruited 419 people. Four people were excluded post-recruitment, leaving 415 adults recruited during 207 randomly assigned admission-days in modified intention-to-treat analysis. At admission, 90.8% (377/415) were taking antiretroviral therapy (ART) with median (IQR) CD4 cell count 240 cells/mm3. In the enhanced diagnostic arm, median CAD4TBv6 score was 60 (IQR: 51-71), 4.4% (9/207) had SILVAMP-LAM-positive and 14.4% (29/201) had Determine-LAM positive urine with three samples positive by both urine tests. TB treatment was initiated in 46/208 (22%) in enhanced TB diagnostics arm and 24/207 (12%) in usual care arm (risk ratio [RR] 1.92, 95% CI 1.20-3.08). There was no difference in mortality by 56 days (enhanced TB diagnosis: 54/208, 26%; usual care: 52/207, 25%; hazard ratio 1.05, 95% CI 0.72-1.53); TB treatment initiation within 24 hours (enhanced TB diagnosis: 8/207, 3.9%; usual care: 5/208, 2.4%; RR 1.61, 95% CI 0.53-4.71); or undiagnosed microbiological-confirmed TB at discharge (enhanced TB diagnosis, 0/207 (0.0%), usual care arm 2/208 (1.0%) (p = 0.50). Urine SILVAMP-LAM/Determine-LAM plus dCXR-CAD diagnostics identified more hospitalised PHIV with TB than usual care. The increase in TB treatment appeared mainly due to greater use of Determine-LAM, rather than SILVAMP-LAM or dCXR-CAD. Poor concordance between Determine-LAM and SILVAMP-LAM urine tests requires further investigation. Inpatient mortality for adults with HIV remains unacceptability high.

Progress in lipoarabinomannan antigen detection for tuberculosis diagnosis in people living with HIV/AIDS

Tuberculosis (TB) is the leading cause of death among people living with HIV/AIDS (PLWHA), posing a significant disease burden. Early TB screening in PLWHA is a key intervention to reduce transmission and control disease progression. ​Lipoarabinomannan (LAM) is a glycolipid of Mycobacterium tuberculosis (MTB) that can be detected in the urine of tuberculosis patients. LAM is useful for the rapid and accurate diagnosis of tuberculosis. This article reviews LAM and its application and limitations in the diagnosis of PLWHA, hoping to provide a reference for the diagnosis of tuberculosis in PLWHA.

Novel automated AIMLAM for diagnosis of Mycobacterium tuberculosis.

Aim: A rapid and precise diagnostic method is crucial for timely intervention and management of tuberculosis. The present study compared the diagnostic accuracy of a novel lipoarabinomannan (LAM) antigen test, AIMLAM, for tuberculosis in urine samples. Methodology: The study subjected 106 TB suspects to smear microscopy, MGIT, GeneXpert and AIMLAM. Results: Among 106, smear microscopy identified 36 as positive (33%) (sensitivity; 70.93%, 95% CI (60.14-80.22%), while MGIT showed 38 positive (36.8%). GeneXpert detected 59 positives (sensitivity; 96.83, 95% CI (89.00-99.61%)). AIMLAM declared 61 as positive (57.5%) (sensitivity; 100.00, 95% CI (94.13-100.00%) and 45 as negative (42.5%). Conclusion: Overall, AIMLAM demonstrated better diagnostic accuracy than GeneXpert Assay, smear microscopy and MGIT liquid culture in urine samples.

Evaluation of the efficacy of urine-based lipoarabinomannan antigen test in the diagnosis of pulmonary tuberculosis

Objective: To analyze the diagnostic efficacy of urinary lipoarabinomannan (LAM) antigen detection method in tuberculosis patients, and to provide an experimental basis for the clinical application of urinary LAM kit in China. Methods: From March to May 2023, 228 patients with lung diseases [134 male, 94 female, age 20-82 (44.8±16.7) years] were prospectively collected in Beijing Chest Hospital, Capital Medical University, including 143 pulmonary tuberculosis patients and 85 non-tuberculosis patients. Urine and sputum samples from patients were collected for traditional etiological detection and urinary LAM antigen detection. The screening results of each positive detection combination were analyzed, and the difference analysis and regression analysis were performed. Results: The detection sensitivity and specificity of the urinary LAM kit were 46.2% (95%CI: 37.9%-54.7%) and 96.5% (95%CI: 89.3%-99.1%), respectively, with an overall coincidence rate of 64.9%. The detection rate of LAM antigen detection and GeneXpert MTB/RIF (Xpert) combined (60.8%, 87/143) was significantly higher than that of Xpert alone (49.7%, 71/143), and the difference was statistically significant (P<0.05). The results of risk factor analysis showed that the risk of negative urinary LAM antigen test results increased significantly as the bacterial load decreased. Conclusions: Urine LAM antigen detection method has a high specificity and can be combined with traditional methods to effectively improve the detection rate. Urinary LAM antigen detection method still has limitations, such as the influence of bacterial load and the inability to distinguish nontuberculosis mycobacteria samples, which needs further experimental verification.

Diagnostic value of chemiluminescence for urinary lipoarabinomannan antigen assay in active tuberculosis: insights from a retrospective study.

This study aimed to assess the efficacy of chemiluminescence-based urinary lipoarabinomannan (LAM) antigen assay as a diagnostic tool for identifying active tuberculosis. A retrospective study was conducted on 166 Tuberculosis (TB), 22 Non-Tuberculous Mycobacteria (NTM), 69 Non-TB cases, and 73 healthy controls from Zhangjiagang First Peoples Hospital between July 2022 and November 2022. Clinical and laboratory data were collected, including urine samples for LAM antigen detection, sputum samples and pleural effusion for GeneXpert, TB-DNA, and culture. TB group exhibited a higher LAM positivity rate (P < 0.001). CD4 count and diabetes as independent factors influencing the diagnostic accuracy of LAM. The LAM assay showed a sensitivity of 50.6% and a specificity of 95.65%. Notably, LAM's sensitivity was superior to TB-DNA (50.60% vs. 38.16%, P < 0.05). LAM's PTB detection rate was 51.7%, superior to TB-DNA (P = 0.047). Moreover, in EPTB cases, the LAM detection rate was 42.11%, surpassing Gene Xpert (P = 0.042), as well as exceeding the detection rates of TB-DNA and sputum culture. LAM antigen detection using chemiluminescence has demonstrated outstanding clinical diagnostic value for active TB, especially in the diagnosis of extrapulmonary TB. The convenience of sample collection in this diagnostic approach allows for widespread application in the clinical diagnosis of active tuberculosis, particularly in cases of EPTB and sputum-negative patients.

Breakthrough of chemiluminescence-based LAM urine test beyond HIV-positive individuals: Clinical diagnostic value of pulmonary tuberculosis in the general population.

To investigate the diagnostic value of a novel high-sensitivity urine lipoarabinomannan (LAM) test (chemiluminescence-based) for active tuberculosis in the general population. A retrospective study was conducted on 250 clinical suspected tuberculosis patients who were HIV-negative and visited the Fourth People's Hospital of Foshan from January 2022 to December 2022. Among them, there were 135 cases of pulmonary tuberculosis, 34 cases of extrapulmonary tuberculosis, and 81 cases of non-tuberculosis. Urine samples were collected for LAM antigen detection before treatment, and laboratory data of sputum smear acid-fast staining (smear method), sputum culture, and GeneXpert method were collected. Using clinical diagnosis as the reference standard, the diagnostic efficacy of 4 methods for detecting active tuberculosis was evaluated. For the 135 cases of pulmonary tuberculosis, the sensitivity of sputum smears, sputm culture, sputm GeneXpert method, and urine LAM were 29.6% (40/135), 45.9% (62/135), 59.3% (80/135), and 51.9% (70/135), respectively. The combination of LAM + GeneXpert and LAM + culture had the highest sensitivity for detecting active pulmonary tuberculosis, which were 71.0% and 78.2%, respectively. For the detection of sputum culture-negative pulmonary tuberculosis, the positive rates of smear, GeneXpert, and LAM were 0.0% (0/73), 53.4% (39/73), and 52.1% (38/73), respectively. LAM + smear and LAM + Genexpert could detect 52.1% and 68.5% of sputum culture-negative patients, respectively. The high-sensitivity urine LAM test holds promise for tuberculosis diagnosis in the general population. It demonstrates high-sensitivity, enabling the detection of sputum culture-negative pulmonary tuberculosis patients. Furthermore, when combined with existing methods, it can enhance the overall detection rate.

The Efficiency of TB LAM Antigen Test to Xpert MTB/RIF Ultra Test for the Diagnosis of Tuberculous Pericarditis Using Pericardial Fluid Samples.

Medical considerations for early diagnosis of tuberculous pericarditis (TBP) include Xpert MTB/RIF Ultra and TB lipoarabinomannan (LAM) antigen (Ag) tests, with immunological status influencing the performance of the latter. An evaluation of the efficiency of Xpert MTB/RIF Ultra and TB LAM Ag in detecting TBP was conducted using pericardial fluid samples from 46 patients with suspected TBP. Fifteen patients (34.1%) were diagnosed with TBP according to culture results. TB LAM Ag's sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), positive likelihood ratio (PLR), and negative likelihood ratio (NLR) were 33.3%, 100%, 100%, 74.4%, 0, and 0.67, respectively. The sensitivity, specificity, PLR, NLR, PPV, and NPV of Xpert MTB/RIF Ultra were 80%, 93.1%, 11.6, 0.21, 85.7%, and 90%, respectively. There was an association observed between a positive TB LAM Ag test and HIV status. When compared to the Xpert MTB/RIF Ultra test, TB LAM Ag has lower accuracy for the detection of microbiologically proven tuberculous pericarditis, yet its usage in HIV-positive populations may be worth exploring. The TB LAM Ag assay is not the best first-line test for the diagnosis of tuberculous pericarditis, and it should be used in conjunction with other diagnostic tests.

Immunoassay with Novel Paired Antibodies for Detection of Lipoarabinomannan in the Pleural Fluid and Plasma of Patients with Tuberculous Pleurisy.

Tuberculous pleurisy (TP) is one of the most common forms of extrapulmonary tuberculosis, but its diagnosis is challenging. Lipoarabinomannan (LAM) antigen is a biomarker for Mycobacterium tuberculosis (Mtb) infection. LAM detection has potential as an auxiliary diagnostic method for TP. We have successfully generated five rabbit anti-LAM monoclonal antibodies (BJRbL01, BJRbL03, BJRbL20, BJRbL52, and BJRbL76). Here, anti-LAM antibodies were tested to detect LAM in the pleural fluid and plasma of patients with TP by sandwich enzyme-linked immunosorbent assays (ELISAs). The results revealed that all of the anti-LAM antibodies were successfully used as capture and detection antibodies in sandwich ELISAs. The BJRbL01/BJRbL01-Bio pair showed better performance than the other antibody pairs for detecting mycobacterial clinical isolates and had a limit of detection of 62.5 pg/mL for purified LAM. LAM levels were significantly higher in the pleural fluid and plasma of patients with TP than in those of patients with malignant pleural effusion or the plasma of non-TB, and LAM levels in the pleural fluid and plasma were positively correlated. Moreover, LAM levels in the pleural fluid sample were significantly higher in confirmed TP patients than in clinically diagnosed TP patients. Our studies provide novel LAM detection choices in the pleural fluid and plasma of TP patients and indicate that LAM detection assay has an auxiliary diagnostic value for TP, which may help to improve the diagnosis of TP.

Correlation of TB LAM Ag (Tuberculosis Lipoarabinomannan Antigen) Results from Urine with Adenosine Deaminase Levels from Pleural Fluid Patients with Pulmonary TB Accompanied by Pleural Effusion

Background: One of the newest testing methods for active TB uses TB LAM Antigen, in which lipoarabinomannan (LAM) as the examined substance serves as the main component of the cell wall of M. tuberculosis (MTB) and the degradation product of MTB by macrophages in the human body. Patients with active TB with or without HIV infection may experience a decreased antibody response, which causes LAM not to bind to antibodies so that it can pass through the normal glomerular basement membrane and can be detected in the urine. Lateral flow urine lipoarabinomannan assay (LF-LAM) can detect this material with urine samples from active TB patients. Another TB screening method uses the measurement of adenosine deaminase (ADA) activity. ADA has a very important function for the proliferation and differentiation of lymphoid cells, especially T cells, and assists in the maturation of monocytes into macrophages. Objective: This study aims to qualitatively prove the correlation between the pleural fluid ADA levels of pulmonary TB patients with pleural effusion using the LF-LAM test results and examine the potential of TB LAM Ag, which correlates with increased pleural fluid ADA levels, as a diagnostic tool for diagnosing pulmonary TB. Method: It is an observational analytic study with a crosssectional design. Materials for this study included temporary urine from active TB patients at Dr. Soetomo Regional Public Hospital collected in May-August 2022. The descriptive analysis was conducted using SPSS 25.0. The data were tested for normal distribution and with the homogeneity test of Shapiro-Wilk's data. The statistical analysis was performed using the Mann-Whitney test, while the kappa suitability test was carried out to determine the correlation and level of concordance between the ADA cut-off value of pleural fluid and the TB LAM Ag test results. Results: This study involved 50 subjects consisting of 22 (44%) subjects with ADA test results between 40-100 IU/L compared to 28 subjects (56%) with ADA test results below 40 IU/L. There were 14 (28%) subjects with positive TB LAM Ag test results, consisting of 10 (45%) active TB subjects with a high ADA test cut-off of 40-100 IU/L and 4 (14%) active TB subjects with a low ADA test cut-off below 40 IU/L, with a p-value = 0.012. Conclusions: There is a correlation between TB Lipoarabinomannan antigen test results of TB patients with pleural effusion. TB LAM Ag can be detected positive on ADA test results of < 40 IU/L and more positive in active TB patients with high ADA test results of > 40-100 IU/L. Therefore, the TB LAM Ag test is more sensitive than the ADA test. The cut-off value of the ADA test reached 76.4 U/L, and a positive TB LAM was found.

Lipoarabinomannan (LAM)—a potential biomarker for the diagnosis of tuberculosis from the urine of infected elephants

The spread of tuberculosis (TB) in Asian countries is mainly due to co-existence and close association of humans with elephants and other domestic livestock. Infected animals tend to shed the organism in the preclinical period which risks the transmission of the infection from animals to humans and vice versa. Since tuberculosis infection is chronic and lack specific clinical signs, diagnosis remains challenging. The present study focuses on the utilization of lipoarabinomannan (LAM), a glycolipid for the detection of TB infection in elephants. Usage of urine as the biological sample for the diagnosis makes it more advantageous. Seroprevalence of tuberculosis (TB) in elephants in Kerala were found to be 37.2% (n = 86) using Chembio DPP VetTB assay. Nine (10.46%) out of 86 elephants were positive for AFB and 29 (33.7%) out of 86 elephants were positive for LAM antigen. On comparison of efficiency of LF-LAM assay with that of DPP VetTB assay, LF-LAM assay had a sensitivity of 90.63%, specificity 100%, positive predictive value 100%, negative predictive value 94.7%, accuracy 95.51%, and kappa statistic value 0.924 (p value < 0.001). On comparison of LF-LAM with traditional acid fast staining method, LF-LAM assay had the sensitivity of 100%, specificity 74.03%, positive predictive value 31%, negative predictive value 100%, accuracy 76.74%, and kappa statistic value 0.374 (p value < 0.001). The presence of Mycobacterium tuberculosis was confirmed in trunk wash sample using PCR targeting gene IS6110, at 245 bp amplicon size and 25 seropositive elephants (78.2%) were confirmed positive. Custom sequencing and phylogenetic analysis revealed that the isolate obtained was Mycobacterium tuberculosis. This study in elephants prove that TB LAM Ag (LF-LAM) can be used as potent biomarker for diagnosis of tuberculosis in elephants.

Enhanced Serum IgG Detection Potential Using 38KD-MPT32-MPT64, CFP10-Mtb81-EspC Fusion Protein and Lipoarabinomannan (LAM) for Human Tuberculosis.

For the rapid, reliable, and cost-effective methods of tuberculosis (TB) auxiliary diagnosis, antibody (Ab) detection to multiple antigens of Mycobacterium tuberculosis (Mtb) has great potential; however, this methodology requires optimization. We constructed 38KD-MPT32-MPT64, CFP10-Mtb81-EspC, and Ag85B-HBHA fusion proteins and evaluated the serum Ab response to these fusion proteins and to lipoarabinomannan (LAM) by ELISA in 50 TB patients and 17 non-TB subjects. IgG responses to the three fusion proteins and to LAM were significantly higher in TB patients, especially in Xpert Mtb-positive TB patients (TB-Xpert+), than in non-TB subjects. Only the anti-38KD-MPT32-MPT64 Ab showed higher levels in the Xpert Mtb-negative TB patients (TB-Xpert-) than in the non-TB, and only the anti-LAM Ab showed higher levels in the TB-Xpert+ group than in the TB-Xpert- group. Anti-Ag85B-HBHA Ab-positive samples could be accurately identified using 38KD-MPT32-MPT64. The combination of 38KD-MPT32-MPT64, CFP10-Mtb81-EspC, and LAM conferred definite complementarity for the serum IgG detection of TB, with relatively high sensitivity (74.0%) and specificity (88.2%). These data suggest that the combination of 38KD-MPT32-MPT64, CFP10-Mtb81-EspC, and LAM antigens provided a basis for IgG detection and for evaluation of the humoral immune response in patients with TB.

Diagnostic accuracy of urine based lipoarabinomannan point of care tuberculosis diagnostic test in HIV negative children: a systematic review and meta-analysis

Tuberculosis is predicted to be a major undocumented cause of mortality in children. This systematic review with meta-analysis assessed the diagnostic accuracy of Lipoarabinomannan antigen testing (FujiLAM) in urine in HIV-negative children with TB-like signs and symptoms. PubMed, EMBASE, Scopus, Cochrane database and Google Scholar search engine were searched to identify relevant studies from earliest records to June 2022 without any language restriction. Three studies were finalized, patients were recruited from Africa and Haiti. Among microbiologically confirmed pediatric TB patients, pooled sensitivity and specificity of FujiLAM (with 95% CI) was 52% (35%-69%) and 90% (85%-93%) respectively. In both clinical (unconfirmed) and microbiological confirmed TB cases, sensitivity reduced to 24% (16%-34%) while specificity was 91%(80%-97%). We concluded that due to ease in obtaining urine sample, FujiLAM can be used as point-of-care TB test in HIV negative children, however more data from different population is needed.

Urine-lipoarabinomannan-might fill the gap in delayed diagnosis of life-threatening tuberculosis

Mycobacterium tuberculosis bacilli is a causative organism for tuberculosis disease. The lungs are the most commonly affected organ with this infection but it can infect any vital organ of the body. The person with signs and symptoms of tuberculosis disease was identified with detection of acid-fast bacilli in the biological specimen and with rapid molecular testing. However, the limiting factor for the early tuberculosis (Tb) diagnosis is the running cost of the diagnostic test. It is the common reason preventing the advancement of diagnostic laboratories in low and middle-income countries. The person and community both suffered from this diagnostic delay. This delay causes significant morbidity and mortality in the patient. An alternate test and an alternate sample that can be easily obtained would be beneficial to prevent these diagnostic delay issues. Lipoarabinomannan (LAM) antigen detection in the urine sample is one such promising diagnostic test. Mycobacterium tuberculosis’s inner layer is made up of glycolipids. LAM is derived from phosphatidylinositol. LAM is a heat-stable amphiphilic cell wall component. It is the precursor of phosphatidyl-inositol-mannosidase and lipomannan. An extra mannose cap is a characteristic feature of a virulent strain of Mycobacterium. LAM has immunogenic and immunomodulatory properties. It is a promising diagnostic test because it is simple to do, the assay can be performed at the patient’s bedside and takes a while to perform. This assay sensitivity varies from 56% to 85% and it has greater than 88% specificity. In HIV seropositive patients, use of LAM assay can reduce 8-week mortality. LAM detection is also a very good assay for the detection of tuberculosis in renal failure and disseminated tuberculosis patients.Lipoarabinomannan detection in the urine is a possible test that can prevent delay in diagnosis. This is a promising test because it's easy to perform, the test can be done with a card test besides the patient's bed. It can be used in HIV seropositive patients and various other forms of extra pulmonary tuberculosis. It can be a very useful test for diagnosing a critically ill patient who is not able to produce a target sample.

Diagnostic value of Lipoarabinomannan antigen for detecting Mycobacterium tuberculosis in adults and children with or without HIV infection

ObjectivesEven today, tuberculosis (TB) remains a leading public health problem; yet, the current diagnostic methods still have a few shortcomings. Lipoarabinomannan (LAM) provides an opportunity for TB diagnosis, and urine LAM detection seems to have a promising and widely applicable prospect.Design or methodsFour databases were systematically searched for eligible studies, and the quality of the studies was evaluated using the quality assessment of diagnostic accuracy studies‐2 (QUADAS‐2). Graphs and tables were created to show sensitivity, specificity, likelihood ratios, diagnostic odds ratio (DOR), the area under the curve (AUC), and so on.ResultsBased on the included 67 studies, the pooled sensitivity of urine LAM was 48% and specificity was 89%. In the subgroup analyses, the FujiLAM test had higher sensitivity (69%) and specificity (92%). Furthermore, among patients infected with human immunodeficiency virus (HIV), 50% of TB patients were diagnosed using a urine LAM test. Besides, the CD4+ cell count was inversely proportional to the sensitivity.ConclusionsUrine LAM is a promising diagnostic test for TB, particularly using the FujiLAM in HIV‐infected adults whose CD4+ cell count is ≤100 per μl. Besides, the urine LAM test shows various sensitivities and specificities in different subgroups in terms of age, HIV infection status, CD4+ cell count, and testing method.

Sensitivity of PCR analysis (melting curve method) in diagnosis of Pulmonary Tuberculosis (PTB) based on Bronchoalveolar Lavage (BAL) by bronchoscope.

Objectives:To evaluate the sensitivity of the real-time PCR assay melting curve method in the diagnosis of pulmonary tuberculosis (PTB) by analyzing bronchoalveolar lavage fluid (BALF) obtained from bronchoscopy.Methods:A total of 214 PTB patients who were treated at Xuancheng People’s Hospital respiratory and infection department during January 2018 to January 2021 were included in this study. Bronchoscopic bronchoalveolar lavage fluid (BALF) examined by polymerase chain reaction (melting curve method), BALF smear, BALF culture, lipoarabinomannan (LAM) antigen test for diagnosis of tuberculosis (TB) (LAM-TB), acid-fast stain (AFS), and serum adenosine deaminase (ADA) test were conducted respectively to compare their positive predictive values (PPVs).Results:Of the 214 patients with confirmed PTB, 84.11% were BALF melting curve method positive, significantly higher than the positive results yielded by other PTB screening tests, i.e., LAM-TB (69.16%), AFS (51.87%), ADA (49.07%), BALF culture (62.15%), and BALF smear (41.12%) (p<0.05, respectively). The PPVs were increased to 92.06%, 93.93%, 92.99%, 95.79%, and 91.12% when BALF melting curve method was performed in combination with LAM-TB, AFS, ADA, BALF culture, and BALF smear, respectively, significantly higher than that produced by BALF melting curve method or the combined use of any two of the non-BALF melting curve method tests (p<0.05, respectively).Conclusion:BALF melting curve method is an ideal diagnostic approach to PTB, which is of a higher diagnostic value compared with LAM-TB, AFS, ADA, BALF culture, and BALF smear.

Significant Improvement in Tuberculosis Diagnosis by Detection of the Wall &amp;lt;i&amp;gt;Lipoarabinomannan&amp;lt;/i&amp;gt; from &amp;lt;i&amp;gt;Mycobacterium tuberculosis&amp;lt;/i&amp;gt; in Central African Republic (CAR)

Background and Objective: Tuberculosis is one of the leading causes of morbi-mortality, especially in developing countries, due to delayed diagnosis and management. The goal of this study is to assess the contribution of lipoarabinomannan (LAM) in improving tuberculosis (TB) diagnosis in the Central African Republic (C.A.R.). Methods: We conducted a retrospective study at the the Regional University Hospital of Bria. The records of patients hospitalized, tested by Determine® TB LAM Antigen Ag (Alere, Medical Co, LTD, Chiba, Japan) immunochromatographic test for the detection of LAM in urine, associated or not with acid-fast bacilli (AFB) research by Ziehl-Neelsen stain, were selected from August to October 2020. Results: During this study, 152 files were selected. Among them, there were 50.0% of children aged 14 or less (≤14 years: 33.6% + 16.4%) and 50.0% of adults represented. Patients living in the displaced person camp represented a larger group (65.1%) than those in the other 2 sites. There were seventy-four patients (i.e 48.7%) who did not benefit from screening for AFB. For the other seventy-eight (i.e. 51.3%), there were 17.1% positive results for the search of AFB. However, among the 152 patients, there was a positive HIV serology in 30.9% of cases (i.e. 47 out of 152) and a positive Determine® TB LAM Ag in 38.2% of cases (i.e. 58 out of 152). It appears that Determine® TB LAM Ag was significantly more able to diagnose tuberculosis than AFB (p 0.003). The 58 patients diagnosed with TB LAM included 20 children who could not provide sputum and HIV-infected patients (p 0.03). Conclusion: The results of this study showed that the microscopy for AFB made it possible to make the diagnosis of tuberculosis in 17.1% of patients against 38.2% for the Alere Determine® TB LAM Ag test. This result highlights the need for routine use of LAM detection to improve the diagnosis of tuberculosis. The conduct of a subsequent study combining Xpert MTB/RIF would improve the diagnosis of tuberculosis using all 3 tests.

Potential value of urine lateral-flow lipoarabinomannan (LAM) test for diagnosing tuberculosis among severely acute malnourished children.

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.

Urine Lipoarabinomannan Testing in Adults With Advanced Human Immunodeficiency Virus in a Trial of Empiric Tuberculosis Therapy.

BackgroundThe urine lipoarabinomannan (LAM) antigen test is a tuberculosis (TB) diagnostic test with highest sensitivity in individuals with advanced human immunodeficiency virus (HIV). Its role in TB diagnostic algorithms for HIV-positive outpatients remains unclear.MethodsThe AIDS Clinical Trials Group (ACTG) A5274 trial demonstrated that empiric TB therapy did not improve 24-week survival compared to isoniazid preventive therapy (IPT) in TB screen–negative HIV-positive adults initiating antiretroviral therapy with CD4 counts <50 cells/µL. Retrospective LAM testing was performed on stored urine obtained at baseline. We determined the proportion of LAM-positive participants and conducted modified intent-to-treat analysis excluding LAM-positive participants to determine the effect on 24-week survival, TB incidence, and time to TB using Kaplan-Meier method.ResultsA5274 enrolled 850 participants; 53% were male and the median CD4 count was 18 (interquartile range, 9–32) cells/µL. Of the 850, 566 (67%) had LAM testing (283 per arm); 28 (5%) were positive (21 [7%] and 7 [2%] in the empiric and IPT arms, respectively). Of those LAM-positive, 1 participant in each arm died and 5 of 21 and 0 of 7 in empiric and IPT arms, respectively, developed TB. After excluding these 28 cases, there were 19 and 21 deaths in the empiric and IPT arms, respectively (P = .88). TB incidence remained higher (4.6% vs 2%, P = .04) and time to TB remained faster in the empiric arm (P = .04).ConclusionsAmong outpatients with advanced HIV who screened negative for TB by clinical symptoms, microscopy, and Xpert testing, LAM testing identified an additional 5% of individuals with TB. Positive LAM results did not change mortality or TB incidence.

Accuracy of the tuberculosis point-of-care Alere determine lipoarabinomannan antigen diagnostic test using α-mannosidase treated and untreated urine in a cohort of people living with HIV in Guatemala

BackgroundImproved point-of-care diagnostic tests for tuberculosis (TB) in severe immune suppressed people living with HIV (PLWH) are needed to decrease morbidity and mortality outcomes. The aim of the study is to evaluate the performance of the lipoarabinomannan antigen test (LAM-test) with and without α-mannosidase pre-treated urine in a cohort of PLWH in primary care clinics in Guatemala. We further determined TB incidence, and mortality rates and its risk factors in PLWH with TB symptoms.MethodsProspective longitudinal study of PLWH with TB symptoms. Urine samples were collected at 2 HIV sites to test the sensitivity of the LAM-test in urine with and without α-mannosidase pre-treatment. A composite reference standard of either a positive Mycobacterium tuberculosis complex culture and/or GeneXpert® MTB/RIF (Xpert, Cepheid, Sunnyvale, CA, USA) results was used in the LAM-test diagnostic accuracy studies. Cox proportional hazards regression was used to study mortality predictors.ResultsThe overall sensitivity of the LAM-test was of 56.1% with 95% CI of (43.3–68.3). There were no differences in the LAM-test sensitivity neither by hospital nor by CD4 T cell values. LAM-test sensitivity in PLWH with < 200 CD4 T cells/µl was of 62.2% (95% CI 46.5–76.2). There were no significant differences in sensitivity when comparing LAM-test results obtained from untreated vs. α-mannosidase treated urine [55.2% (95% CI 42.6–67.4) vs. 56.9% (95% CI 44–69.2), respectively]. TB incidence in our cohort was of 21.4/100 person years (PYs) (95% CI 16.6–27.6), and mortality rate was of 11.1/100 PYs (95% CI 8.2–15.0). Importantly, PLWH with a positive LAM-test result had an adjusted hazard ratio (aHR) of death of 1.98 (1.0–3.8) with a significant p value of 0.044 when compared to PLWH with a negative LAM-test result.ConclusionsIn this study, α-mannosidase treatment of urine did not significantly increase the LAM-test performance, however; this needs to be further evaluated in a large-scale study due to our study limitations. Importantly, high rates of TB incidence and mortality were found, and a positive LAM-test result predicted mortality in PLWH with TB clinical symptoms.