Dataset Information

Brief Report: Real-World Performance and Interobserver Agreement of Urine Lipoarabinomannan in Diagnosing HIV-Associated Tuberculosis in an Emergency Center.

ABSTRACT: BACKGROUND:The urine lipoarabinomannan (LAM) lateral flow assay is a point-of-care test to diagnose HIV-associated tuberculosis (TB). We assessed the performance of urine LAM in HIV-positive patients presenting to the emergency center and evaluated the interobserver agreement between emergency center physicians and laboratory technologists. SETTING:A cross-sectional diagnostic study was performed at the emergency center of a district hospital in a high HIV-prevalence community in South Africa. METHODS:Consecutive HIV-positive adults presenting with ?1 WHO TB symptom were enrolled over a 16-month period. A urine LAM test was performed at point-of-care by an emergency physician and interpreted independently by 2 physicians. A second test was performed in the laboratory and interpreted independently by 2 laboratory technologists. The reference standard was a positive TB culture or Xpert MTB/RIF test on sputum or appropriate extrapulmonary samples. We compared diagnostic accuracy and reproducibility of urine LAM between point-of-care readers and laboratory readers. RESULTS:One thousand three hundred eighty-eight samples (median, 3 samples/participant) were sent for TB microbiology tests in 411 participants; 170 had confirmed TB (41.4%). Point-of-care and laboratory-performed urine LAM had similar sensitivity (41.8% vs 42.0%, P = 1.0) and specificity (90.5% vs 87.5%, P = 0.23). Moderate agreement was found between point-of-care and laboratory testing (? = 0.62), but there was strong agreement between point-of-care readers (? = 0.95) and between laboratory readers (? = 0.94). Positive percent agreement between point-of-care and laboratory readers was 68% and negative percent agreement 92%. CONCLUSION:There is no diagnostic accuracy advantage in laboratory-performed versus point-of-care-performed urine LAM tests in emergency care centers in high-burden settings.

SUBMITTER: Van Hoving DJ

PROVIDER: S-EPMC6522362 | biostudies-literature | 2019 May

REPOSITORIES: biostudies-literature

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Brief Report: Real-World Performance and Interobserver Agreement of Urine Lipoarabinomannan in Diagnosing HIV-Associated Tuberculosis in an Emergency Center.

Van Hoving Daniël J DJ Lahri Saʼad S Lategan Hendrick J HJ Nicol Mark P MP Maartens Gary G Meintjes Graeme G

Journal of acquired immune deficiency syndromes (1999) 20190501 1

<h4>Background</h4>The urine lipoarabinomannan (LAM) lateral flow assay is a point-of-care test to diagnose HIV-associated tuberculosis (TB). We assessed the performance of urine LAM in HIV-positive patients presenting to the emergency center and evaluated the interobserver agreement between emergency center physicians and laboratory technologists.<h4>Setting</h4>A cross-sectional diagnostic study was performed at the emergency center of a district hospital in a high HIV-prevalence community in ...[more]

PMID: 30865176

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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:BackgroundUp to one third of HIV-infected individuals with suspected TB are sputum-scarce. The Alere Determine™ TB LAM Ag lateral flow strip test can be used to diagnose TB in HIV-infected patients with advanced immunosuppression. However, how urine LAM testing should be incorporated into testing algorithms and in the context of specific patient sub-groups remains unclear.MethodsThis study represents a post hoc sub-group analysis of data from a randomized multi-center parent study. The study population consisted of hospitalized HIV-infected patients with suspected TB who were unable to produce sputum and who underwent urine LAM testing. The diagnostic utility of urine LAM for TB in this group was compared to the performance of urine LAM in patients who did produce a sputum sample in the parent study.ResultsThere were a total of 187 and 2341 patients in the sputum-scarce and sputum-producing cohorts, respectively. 80 of the sputum-scarce patients underwent testing with urine LAM. In comparison to those who did produce sputum, sputum-scarce patients had a younger age, a lower Karnofsky performance score, and a lower weight and BMI at admission. A greater proportion of sputum-scarce patients were urine LAM positive, compared to those who were able to produce sputum (31% vs. 21%, p = 0.04). A higher proportion of sputum-scarce patients died within 8 weeks of admission (32% vs. 24%, p = 0.013). We inferred that 19% of HIV-infected sputum-scarce patients suspected of TB were diagnosed with tuberculosis by urine LAM testing, with an estimated positive predictive value of 63% (95% CI 43-82%).ConclusionsUrine LAM testing can effectively identify tuberculosis in HIV-infected patients who are at a higher risk of mortality yet are unable to generate a sputum sample for diagnostic testing. Our findings support the use of urine LAM testing in sputum-scarce hospitalized HIV-infected patients, and its incorporation into diagnostic algorithms for this patient population.

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:BackgroundFor several decades, emergency departments (EDs) utilization has increased, inducing ED overcrowding in many countries. This phenomenon is related partly to an excessive number of nonurgent patients. To resolve ED overcrowding and to decrease nonurgent visits, the most common solution has been to triage the ED patients to identify potentially nonurgent patients, i.e. which could have been dealt with by general practitioner. The objective of this study was to measure agreement among ED health professionals on the urgency of an ED visit, and to determine if the level of agreement is consistent among different sub-groups based on following explicit criteria: age, medical status, type of referral to the ED, investigations performed in the ED, and the discharge from the ED.MethodsWe conducted a multicentric cross-sectional study to compare agreement between nurses and physicians on categorization of ED visits into urgent or nonurgent. Subgroups stratified by criteria characterizing the ED visit were analyzed in relation to the outcome of the visit.ResultsOf 1,928 ED patients, 350 were excluded because data were lacking. The overall nurse-physician agreement on categorization was moderate (kappa = 0.43). The levels of agreement within all subgroups were variable and low. The highest agreement concerned three subgroups of complaints: cranial injury (kappa = 0.61), gynaecological (kappa = 0.66) and toxicology complaints (kappa = 1.00). The lowest agreement concerned two subgroups: urinary-nephrology (kappa = 0.09) and hospitalization (kappa = 0.20). When categorization of ED visits into urgent or nonurgent cases was compared to hospitalization, ED physicians had higher sensitivity and specificity than nurses (respectively 94.9% versus 89.5%, and 43.1% versus 30.9%).ConclusionsThe lack of physician-nurse agreement and the inability to predict hospitalization have important implications for patient safety. When urgency screening is used to determine treatment priority, disagreement might not matter because all patients in the ED are seen and treated. But using assessments as the basis for refusal of care to potential nonurgent patients raises legal, ethical, and safety issues. Managed care organizations should be cautious when applying such criteria to restrict access to EDs.

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

Brief Report: Real-World Performance and Interobserver Agreement of Urine Lipoarabinomannan in Diagnosing HIV-Associated Tuberculosis in an Emergency Center.

Publications

Brief Report: Real-World Performance and Interobserver Agreement of Urine Lipoarabinomannan in Diagnosing HIV-Associated Tuberculosis in an Emergency Center.

Similar Datasets

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