The Open Microbiology Journal

ISSN: 1874-2858 ― Volume 13, 2019

Diagnostic Performance of Xpert MTB/RIF Assay Versus Ziehl-Neelsen Method for the Diagnosis of Pulmonary Tuberculosis in Addis Ababa, Ethiopia

Boja D. Taddese1, *, Daniel M. Desalegn1, Abay S. Misganaw2, Kumera T. Kitila1, Tinsae Kidanemariam Hailu1, Abraham T. Bika1
1 Addis Ababa Health Bureau, Public Health Research and Emergency Management, Addis Ababa, Ethiopia
2 Department of Medical Laboratory, College of Health Sciences, School of Allied Health Sciences, Addis Ababa University, Addis Ababa, Ethiopia



Worldwide Tuberculosis (TB) is the ninth leading cause of death from a single infectious agent, positioning on top of Human Immuno Deficiency Virus (HIV) and it is still an eminently serious public health problem. In developing countries, Ziehl-Neelsen (ZN)-stained sputum smear microscopy is the most widely used diagnostic method in diagnosing Pulmonary Tuberculosis (PTB). This study was aimed to compare the diagnostic performances of ZN-method with Xpert MTB/RIF assay for the diagnosis of PTB in Addis Ababa, Ethiopia.


Facility-based cross-sectional study design was conducted from September 2016 to June 2017 on a total of 244 sputum samples collected from presumptive TB patients. The L-J sputum culture was used as a gold standard to compare the diagnostic performances of Xpert MTB/RIF assay and ZN-methods. Kappa values were analyzed by using statistical package for Social Science (SPSS) version 20 software at 95% Confidence Interval (CI). The Sensitivity, Specificity, Positive Predictive Value (PPV) and Negative Predictive Value (NPV) of ZN-stained sputum smear microscopy and Xpert MTB/RIF assay were calculated against the gold standard.


The Sensitivity, Specificity, PPV and NPV of ZN-stained sputum smear microscopy were 68.38%, 95.28%, 93.02% and 76.58% respectively, while for Xpert MTB/ RIF assay were 88.89%, 81.89%, 81.89% and 88.89% respectively. The results of the two diagnostic approaches were concordant with the gold standard with a kappa value of ZN 0.650 and 0.743 for Xpert MTB/RIF assay.


This study concludes that the sensitivity of Xpert MTB/RIF assay was better than ZN-stained direct sputum smear microscopy for the diagnosis of pulmonary tuberculosis.

Keywords: Addis Ababa, Ethiopia, Xpert MTB/RIF assay, ZN, Pulmonary tuberculosis, Negative Predictive Value (NPV).

Article Information

Identifiers and Pagination:

Year: 2018
Volume: 12
First Page: 390
Last Page: 396
Publisher Id: TOMICROJ-12-390
DOI: 10.2174/1874285801812010390

Article History:

Received Date: 31/7/2018
Revision Received Date: 10/11/2018
Acceptance Date: 15/11/2018
Electronic publication date: 30/11/2018
Collection year: 2018

Article Metrics:

CrossRef Citations:

Total Statistics:

Full-Text HTML Views: 481
Abstract HTML Views: 417
PDF Downloads: 155
ePub Downloads: 95
Total Views/Downloads: 1148

Unique Statistics:

Full-Text HTML Views: 343
Abstract HTML Views: 325
PDF Downloads: 113
ePub Downloads: 71
Total Views/Downloads: 852
Geographical View

© 2018 Taddese et al.

open-access license: This is an open access article distributed under the terms of the Creative Commons Attribution 4.0 International Public License (CC-BY 4.0), a copy of which is available at: ( This license permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.

* Address correspondence to this author at the Addis Ababa Health Bureau, Public Health Research and Emergency Management, Addis Ababa, Ethiopia; Tel: +251 91 138 2203; E-mail:


"Open access will revolutionize 21st century knowledge work and accelerate the diffusion of ideas and evidence that support just in time learning and the evolution of thinking in a number of disciplines."

Daniel Pesut
(Indiana University School of Nursing, USA)

"It is important that students and researchers from all over the world can have easy access to relevant, high-standard and timely scientific information. This is exactly what Open Access Journals provide and this is the reason why I support this endeavor."

Jacques Descotes
(Centre Antipoison-Centre de Pharmacovigilance, France)

"Publishing research articles is the key for future scientific progress. Open Access publishing is therefore of utmost importance for wider dissemination of information, and will help serving the best interest of the scientific community."

Patrice Talaga
(UCB S.A., Belgium)

"Open access journals are a novel concept in the medical literature. They offer accessible information to a wide variety of individuals, including physicians, medical students, clinical investigators, and the general public. They are an outstanding source of medical and scientific information."

Jeffrey M. Weinberg
(St. Luke's-Roosevelt Hospital Center, USA)

"Open access journals are extremely useful for graduate students, investigators and all other interested persons to read important scientific articles and subscribe scientific journals. Indeed, the research articles span a wide range of area and of high quality. This is specially a must for researchers belonging to institutions with limited library facility and funding to subscribe scientific journals."

Debomoy K. Lahiri
(Indiana University School of Medicine, USA)

"Open access journals represent a major break-through in publishing. They provide easy access to the latest research on a wide variety of issues. Relevant and timely articles are made available in a fraction of the time taken by more conventional publishers. Articles are of uniformly high quality and written by the world's leading authorities."

Robert Looney
(Naval Postgraduate School, USA)

"Open access journals have transformed the way scientific data is published and disseminated: particularly, whilst ensuring a high quality standard and transparency in the editorial process, they have increased the access to the scientific literature by those researchers that have limited library support or that are working on small budgets."

Richard Reithinger
(Westat, USA)

"Not only do open access journals greatly improve the access to high quality information for scientists in the developing world, it also provides extra exposure for our papers."

J. Ferwerda
(University of Oxford, UK)

"Open Access 'Chemistry' Journals allow the dissemination of knowledge at your finger tips without paying for the scientific content."

Sean L. Kitson
(Almac Sciences, Northern Ireland)

"In principle, all scientific journals should have open access, as should be science itself. Open access journals are very helpful for students, researchers and the general public including people from institutions which do not have library or cannot afford to subscribe scientific journals. The articles are high standard and cover a wide area."

Hubert Wolterbeek
(Delft University of Technology, The Netherlands)

"The widest possible diffusion of information is critical for the advancement of science. In this perspective, open access journals are instrumental in fostering researches and achievements."

Alessandro Laviano
(Sapienza - University of Rome, Italy)

"Open access journals are very useful for all scientists as they can have quick information in the different fields of science."

Philippe Hernigou
(Paris University, France)

"There are many scientists who can not afford the rather expensive subscriptions to scientific journals. Open access journals offer a good alternative for free access to good quality scientific information."

Fidel Toldrá
(Instituto de Agroquimica y Tecnologia de Alimentos, Spain)

"Open access journals have become a fundamental tool for students, researchers, patients and the general public. Many people from institutions which do not have library or cannot afford to subscribe scientific journals benefit of them on a daily basis. The articles are among the best and cover most scientific areas."

M. Bendandi
(University Clinic of Navarre, Spain)

"These journals provide researchers with a platform for rapid, open access scientific communication. The articles are of high quality and broad scope."

Peter Chiba
(University of Vienna, Austria)

"Open access journals are probably one of the most important contributions to promote and diffuse science worldwide."

Jaime Sampaio
(University of Trás-os-Montes e Alto Douro, Portugal)

"Open access journals make up a new and rather revolutionary way to scientific publication. This option opens several quite interesting possibilities to disseminate openly and freely new knowledge and even to facilitate interpersonal communication among scientists."

Eduardo A. Castro
(INIFTA, Argentina)

"Open access journals are freely available online throughout the world, for you to read, download, copy, distribute, and use. The articles published in the open access journals are high quality and cover a wide range of fields."

Kenji Hashimoto
(Chiba University, Japan)

"Open Access journals offer an innovative and efficient way of publication for academics and professionals in a wide range of disciplines. The papers published are of high quality after rigorous peer review and they are Indexed in: major international databases. I read Open Access journals to keep abreast of the recent development in my field of study."

Daniel Shek
(Chinese University of Hong Kong, Hong Kong)

"It is a modern trend for publishers to establish open access journals. Researchers, faculty members, and students will be greatly benefited by the new journals of Bentham Science Publishers Ltd. in this category."

Jih Ru Hwu
(National Central University, Taiwan)

Browse Contents

Webmaster Contact:
Copyright © 2019 Bentham Open