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Updated: Dec 7, 2025
Diagnosing Pulmonary Tuberculosis with the Xpert MTB/RIF Test
Published on: April 9, 2012
Cost analysis of smear microscopy and the Xpert assay for tuberculosis diagnosis: average turnaround time
Lida Jouca de Assis Figueredo1, Silvana Spíndola de Miranda2, Lucas Benício Dos Santos1
1Universidade Federal de Minas Gerais, Laboratório de Pesquisa em Micobactérias, Belo Horizonte, MG, Brasil.
Introduction:
Rapid and accurate tuberculosis detection is critical for improving patient diagnosis and decreasing tuberculosis transmission. Molecular assays can significantly increase laboratory costs; therefore, the average time and economic impact should be evaluated before implementing a new technology. The aim of this study was to evaluate the cost and average turnaround time of smear microscopy and Xpert assay at a university hospital.
Methods:
The turnaround time and cost of the laboratory diagnosis of tuberculosis were calculated based on the mean cost and activity based costing (ABC).
Results:
The average turnaround time for smear microscopy was 16.6 hours while that for Xpert was 24.1 hours. The Xpert had a mean cost of USD 17.37 with an ABC of USD 10.86, while smear microscopy had a mean cost of USD 13.31 with an ABC of USD 6.01. The sensitivity of smear microscopy was 42.9% and its specificity was 99.1%, while the Xpert assay had a sensitivity of 100% and a specificity of 96.7%.
Conclusions:
The Xpert assay has high accuracy; however, the turnaround time and cost of smear microscopy were lower than those of Xpert.
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