Author(s)

Shimba Henerico^1,2, Richard V. Makapa³, Bernard C. Okamo³, Geoffrey Japhet¹, Lisa Gerwing-Adima^4,5, Benson R. Kidenya^3*, Christa Kasang⁴

¹Bugando Medical Centre, Central Pathology Laboratory, Mwanza, Tanzania.
²Division of Medical Virology, Faculty of Medicine and Health Sciences, University of Stellenbosch, Western Cape, South Africa.
³Department of Biochemistry and Molecular Biology, Catholic University of Health and Allied Sciences, Mwanza, Tanzania.
⁴The Germany TB and Leprosy Relief Association, Wurzburg, Germany.
⁵Uganda Catholic Medical Bureau, Kampala, Uganda.

Background: Tuberculosis (TB) diagnostics, such as Xpert MTB/RIF, is still limited by cost. Testing of pooled samples from presumptive TB patients has been thought as a cost-saving strategy to diagnose TB. We assessed the utility and cost-saving of pooled Xpert MTB/RIF testing strategy for the diagnosis of TB in Mwanza, Tanzania. Methods: Sputum samples from Presumptive TB patients were submitted to TB laboratory for routine diagnosis of TB using Xpert MTB/RIF. The TB results from the individual sputum samples were used as the reference standard and were concealed to the investigating laboratory technicians. The remainder of samples were collected serially and were pooled (5 samples per pool) for testing. The agreement of the results between individual sample testing against pooled sample testing and cost-savings was assessed. Results: A total of 250 sputum samples from presumptive TB patients were analyzed and 50 pools were made with each pool containing 5 samples. Of the 50 sputum pools made, Mycobacterium tuberculosis (MTB) was detected in 17 (34.0%) pools. Results from the individual sputum samples MTB/RIF testing were retrieved for all 250 samples and there were 28 (11.2%) samples in which MTB was detected whereas 222 (88.8%) samples had no MTB detected. Following re-analysis of positive pools, all 28 (100%) individual positive MTB samples were detected within the 17 positive pools, with 1 to 3 individual MTB positive samples per pool. The individual sputum samples were correctly identified by pooled sputum on Xpert MTB/RIF testing, with the sensitivity of 100% and specificity of 100%. Using pooling of sputum samples strategy, we saved 46.0% (115/250) of the cartridges. Conclusion: The pooled sputum testing strategy reduced cartridge costs by 46.0% and has the potential to increase the affordability of Xpert MTB/RIF testing in countries with limited resources, such as Tanzania.

Tuberculosis, Pooled Sputum, Xpert MTB/RIF, Cost-Saving, Diagnostic Strategy, Mwanza, Tanzania

Henerico, S. , Makapa, R. , Okamo, B. , Japhet, G. , Gerwing-Adima, L. , Kidenya, B. and Kasang, C. (2023) Pooled Sputum for Xpert MTB/RIF Testing: A Cost-Saving Strategy in Mwanza, Tanzania. Advances in Infectious Diseases, 13, 183-192. doi: 10.4236/aid.2023.132017.