Abstract
Tuberculosis prevalence surveys have demonstrated the benefit of screening with chest x-ray (CXR) and sensitive diagnostic tests compared to symptoms and smear microscopy. However, in programmatic practice there is little evidence on the yield of different algorithms. We implemented contact tracing in Chennai, India for adult sputum-positive TB patients registered from January 2015 to March 2016. Patients with symptoms or abnormal X-ray findings further underwent testing using Xpert MTB/RIF (Xpert) and smear microscopy. A retrospective cohort study was done to summarize the key findings. We verbally screened 5553 contacts for symptoms, CXR through private sector collaboration, Xpert, and smear microscopy. Overall, 1312 (23.6%) contacts screened positive. CXR alone identified 531 (40.5%) of them, 679 (51.8%) were symptom-positive only, while 102 (7.8%) were positive on both the symptom and CXR screen. Overall, 35 bacteriologically positive cases were identified (0.7%). A standard approach of symptoms screening followed by microscopy identified only 9 (25.7%) of the total number of bacteriologically positive cases, whereas the combination of a CRX screening followed by microscopy identified 13 (37.1%) of the cases. The algorithm of symptoms screening followed by Xpert testing, detected 20 cases, whereas the combination of symptoms and CXR followed by Xpert increased this number to 35 (75% increase compared to symptoms and Xpert). Optimal use of more sensitive screening tests, better diagnostic tests, and novel private sector engagement can improve diagnostic yield in a programmatic setting.
Publication types
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Research Support, Non-U.S. Gov't
MeSH terms
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Adolescent
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Adult
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Antibiotics, Antitubercular / pharmacology
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Antibiotics, Antitubercular / therapeutic use
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Contact Tracing / methods*
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Contact Tracing / statistics & numerical data
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Drug Resistance, Bacterial
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Female
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Humans
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India / epidemiology
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Male
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Mass Screening / methods*
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Mass Screening / statistics & numerical data
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Microscopy
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Middle Aged
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Molecular Diagnostic Techniques / statistics & numerical data
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Mycobacterium tuberculosis / isolation & purification*
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Radiography / statistics & numerical data
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Reagent Kits, Diagnostic / statistics & numerical data
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Retrospective Studies
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Rifampin
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Sputum / microbiology*
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Tuberculosis, Pulmonary / diagnosis*
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Tuberculosis, Pulmonary / drug therapy
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Tuberculosis, Pulmonary / epidemiology
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Tuberculosis, Pulmonary / microbiology
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Young Adult
Substances
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Antibiotics, Antitubercular
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Reagent Kits, Diagnostic
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Rifampin
Grants and funding
TB REACH - an initiative of Stop TB Partnership - supported this intervention and is funded by Global Affairs Canada (GAC) grant number CA-3-D000920001.
https://w05.international.gc.ca/projectbrowserbanqueprojets/projectprojet/details/d000920001. The funder provided support in the form of salaries for authors AJC, RS and JC, but did not have any additional role in the study design, data collection and analysis, decision to publish, or preparation of the manuscript. The specific roles of these authors are articulated in the ‘author contributions’ section. RS works as an independent consultant, not affiliated with any organization hence the designation, but it did not play a role in this study.