C-reactive protein-based tuberculosis triage testing: a multi-country diagnostic accuracy study.

Rationale: C-reactive protein (CRP)-based tuberculosis (TB) screening is recommended for people with HIV (PWH). However, its performance among people without HIV and in diverse settings is unknown. Objectives: In a multi-country study, we aimed to determine whether CRP meets the minimum accuracy targets (sensitivity ≥90%, specificity ≥70%) for an effective TB triage test. Methods/Measurements: Consecutive outpatient adults with cough ≥2 weeks from five TB endemic countries in Africa and Asia had baseline blood collected for point-of-care CRP testing and HIV and diabetes screening. Sputum samples were collected for Xpert MTB/RIF Ultra (Xpert) testing and culture. CRP sensitivity and specificity (5 mg/L cut-point) was determined in reference to sputum test results and compared by country, sex, and HIV and diabetes status. Variables affecting CRP performance were identified using a multivariate receiver operating characteristic (ROC) regression model. Results: Among 2904 participants, of whom 613 (21%) had microbiologically-confirmed TB, CRP sensitivity was 84% (95% CI: 81-87%) and specificity was 61% (95% CI: 59-63%). CRP accuracy varied geographically, with higher sensitivity in African countries (≥91%) than Asian countries (64-82%). Sensitivity was higher among men than women (87% vs. 79%, difference +8%, 95% CI: 1-15%) and specificity was higher among people without HIV than PWH (64% vs. 45%, difference +19%, 95% CI: 13-25%). ROC regression identified country and measures of TB disease severity as predictors of CRP performance. Conclusions: Overall, CRP did not achieve the minimum accuracy targets and its performance varied by setting and in some sub-groups, likely reflecting population differences in mycobacterial load.

New Manual Quantitative Polymerase Chain Reaction Assay Validated on Tongue Swabs Collected and Processed in Uganda Shows Sensitivity That Rivals Sputum-based Molecular Tuberculosis Diagnostics.

BACKGROUND: Sputum-based testing is a barrier to increasing access to molecular diagnostics for tuberculosis (TB). Many people with TB are unable to produce sputum, and sputum processing increases assay complexity and cost. Tongue swabs are emerging as an alternative to sputum, but performance limits are uncertain. METHODS: From June 2022 to July 2023, we enrolled 397 consecutive adults with cough >2 weeks at 2 health centers in Kampala, Uganda. We collected demographic and clinical information, sputum for TB testing (Xpert MTB/RIF Ultra and 2 liquid cultures), and tongue swabs for same-day quantitative polymerase chain reaction (qPCR) testing. We evaluated tongue swab qPCR diagnostic accuracy versus sputum TB test results, quantified TB targets per swab, assessed the impact of serial swabbing, and compared 2 swab types (Copan FLOQSWAB and Steripack spun polyester). RESULTS: Among 397 participants, 43.1% were female, median age was 33 years, 23.5% were diagnosed with human immunodeficiency virus, and 32.0% had confirmed TB. Sputum Xpert Ultra and tongue swab qPCR results were concordant for 98.2% (95% confidence interval [CI]: 96.2-99.1) of participants. Tongue swab qPCR sensitivity was 92.6% (95% CI: 86.5 to 96.0) and specificity was 99.1% (95% CI: 96.9 to 99.8) versus microbiological reference standard. A single tongue swab recovered a 7-log range of TB copies, with a decreasing recovery trend among 4 serial swabs. Swab types performed equivalently. CONCLUSIONS: Tongue swabs are a promising alternative to sputum for molecular diagnosis of TB, with sensitivity approaching sputum-based molecular tests. Our results provide valuable insights for developing successful tongue swab-based TB diagnostics.

New manual qPCR assay validated on tongue swabs collected and processed in Uganda shows sensitivity that rivals sputum-based molecular TB diagnostics.

Background: Reliance on sputum-based testing is a key barrier to increasing access to molecular diagnostics for tuberculosis (TB). Many people with TB are unable to produce and sputum processing increases the complexity and cost of molecular assays. Tongue swabs are emerging as an alternative to sputum, but performance limits are uncertain. Methods: From June 2022 to July 2023, we enrolled 397 consecutive adults with cough >2 weeks at two health centers in Kampala, Uganda. We collected routine demographic and clinical information, sputum for routine TB testing (one Xpert MTB/RIF Ultra® and two liquid cultures), and up to four tongue swabs for same-day qPCR. We evaluated tongue swab qPCR diagnostic accuracy in reference to sputum TB test results, quantified TB targets per swab, assessed the impact of serial swabbing, and compared two swab types (Copan FLOQSWAB® and Steripack® spun polyester swabs). Results: Among 397 participants, 43.1% were female, median age was 33 years, 23.5% were living with HIV (PLHIV) and 32.3% had confirmed TB. Sputum Xpert Ultra and tongue swab qPCR results were concordant for 98.2% [96.2-99.1] of participants. Tongue swab qPCR sensitivity was 91.0% [84.6-94.9] and specificity 98.9% [96.2-99.8] vs. microbiological reference standard (MRS). A single tongue swab recovered a seven-log range of TB copies, with a decreasing recovery trend among four serial swabs. We found no difference between swab types. Conclusions: Tongue swabs show promise as an alternative to sputum for TB diagnosis, with sensitivity approaching sputum-based molecular tests. Our results provide valuable insights for developing successful tongue swab-based TB diagnostics.

Can Primary Care Drive Tuberculosis Elimination? Increasing Latent Tuberculosis Infection Testing and Treatment Initiation at a Community Health Center with a Large Non-U.S.-born Population.

Community health centers (CHC) play a key role in latent tuberculosis infection (LTBI) testing and treatment. We performed a retrospective analysis of LTBI testing and treatment among pediatric and adult patients at a CHC with a large non-U.S.-born (USB) population during a series of quality improvement (QI) interventions from 2010 to 2019. Among 124,695 patients with primary care visits, 40% of patients were tested for tuberculosis (TB) infection and among those tested, 20% tested positive, including 39% of adults aged 50-79 years. Compared to adults aged 18-49 years, children aged 6-17 had increased odds of LTBI testing and treatment initiation [odds ratio and 95% confidence interval 3.23 (3.10, 3.36) and 1.41 (1.12, 1.79), respectively], while age ≥ 65 was associated with lower odds of both testing and treatment initiation. Over the analysis period, coinciding with unfunded QI interventions intended to reduce barriers to LTBI care, there was a significant increase in the proportion of patients receiving LTBI testing for both adults (6% to 47%, p < 0.001) and children (23% to 80%, p < 0.001). During the analysis period, there was also a significant increase in the proportion of patients receiving prescriptions for LTBI treatment, as well as provider use of evidence-based strategies including rifamycin-based treatment. Our study suggests that primary care interventions can reduce barriers to LTBI treatment and drive TB elimination.

Latent Tuberculosis Infection Testing and Treatment at a Federally Qualified Health Center in Southern California: A Quality Improvement Project.

BACKGROUND: A key strategy to eliminate tuberculosis (TB) in the United States is to increase latent tuberculosis infection (LTBI) screening, testing, and treatment among non-US-born Asian populations. PURPOSE: The purpose was to increase LTBI screening, testing, and treatment at a community clinic. METHODS: Retrospective baseline LTBI data were retrieved through electronic medical record review. Interventions included adoption of standardized TB risk assessment, training providers to use shorter LTBI treatment regimens, and use of a care coordinator. Chart abstraction to examine outcomes was conducted postintervention at 4 months. RESULTS: In 2017, only 3 patients (7%) with LTBI were started on treatment. At 4 months postintervention, 28 (72%) patients with LTBI were started on treatment, of which 27 (96%) were placed on 3- to 4-month regimens. CONCLUSIONS: Training for providers and changes to clinic workflow, including use of a care coordinator, can help increase LTBI screening, testing, and treatment in community clinics.