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Comparative Study
. 2019 May 16;19(1):424.
doi: 10.1186/s12879-019-4070-8.

Comparative study of OMNIgene®•SPUTUM reagent versus cold-chain for the transportation of sputum samples to GeneXpert®MTB/RIF testing sites in Malawi

Wondwossen A Alemayehu  1 , S Neri  2 , S Dalebout  2 , R Nalikungwi  2 , A Trusov  2 , E Ahmed  2 , A Dimba  3 , A Weirich  4 , P S Curry  4 , C D Kelly-Cirino  4
Affiliations
Comparative Study

Comparative study of OMNIgene®•SPUTUM reagent versus cold-chain for the transportation of sputum samples to GeneXpert®MTB/RIF testing sites in Malawi

Wondwossen A Alemayehu et al. BMC Infect Dis. .

Abstract

Background: The study was conducted in a remote sputum sample collection sites and GeneXpert® MTB/RIF testing centers to detect Mycobacterium tuberculosis in Malawi. The main purpose of the study was to evaluate whether sputum samples stored and transported with OMNIgene®•SPUTUM (OM-S) medium perform comparably to the routine cold-chain stored and transported samples for GeneXpert testing to detect Mycobacterium tuberculosis.

Methods: Two sputum samples from each of 362 tuberculosis suspects were randomly assigned to the OMNIgene treated (OM-S group) or the standard-of-care group (SOC; transported via cold chain). All specimens were tested at regional GeneXpert testing sites using the expectorated (raw) sputum protocol. Demographic, clinical, transport/storage and Xpert data were recorded for each specimen pair. Agreement between the SOC and OM-S groups' Xpert results was evaluated using Cohen's kappa analysis.

Results: Mean patient age was 42.3 years (range 2-79 years), 77% of patients were female, and 80% were HIV-positive. Mean transport/storage time was 6.7 days (range, 0-29 days). The rates of MTB positivity for the OM-S and SOC groups were comparable (11.8 and 11.2%, respectively), inter-test agreement was "very good" (κ = 0.97), and overall percent agreement was 99%. Two specimen pairs (both mucoid, one 13 days transport, one 1 day transport) had discordant Xpert results.

Conclusion: OM-S-treated sputum specimens can undergo multi-day ambient-temperature storage as well as transport and yield Xpert results comparable to those of cold-chain-transported samples in Malawi.

Keywords: GeneXpert; Molecular detection; Mycobacterium tuberculosis; OMNIgene; Preservation; Specimen transport medium; Sputum.

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Conflict of interest statement

Ethics approval and consent to participate

Study participants were informed about the purpose, process, and possible outcomes of the study by the health workers collecting the sputum samples. Anticipating most of the study participants or care givers may not have the literacy level to read and provide written consent, informed verbal consent was sought from all study participants for consistency purpose. For children under 18 years old, consent was obtained from their parents or guardians accompanying them after they were informed about the study by the health workers in the facility. There was no personal identifier in the data collection tool except the sample unique identification code. Any data obtained from the study participant was not shared or disclosed in a manner that breaches confidentiality. Project HOPE has got prior ethical clearance from National Health Sciences Research Committee (NHSRC) to conduct the study.

Consent for publication

Since there are no individual images or clinical data with personal identifier consent for publication is not applicable.

Competing interests

DNA Genotek provided financial support to Project HOPE - Malawi in the form of reimbursement for consumables and reagents used during the study. A. Weirich, P.S. Curry and C.D. Kelly-Cirino were employed by DNA Genotek during the course of the study.

Publisher’s Note

Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.

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