EC Pulmonology and Respiratory Medicine

Research Article Volume 10 Issue 8 - 2021

Diagnostic Accuracy of Direct Smear Microscopy Using Culture as a Gold Standard, among Pulmonary Tuberculosis Patients in Anambra State, Nigeria

Ngozichukwu Gertrude Uzoewulu1*, Nkiru Nwamaka Ezeama2 and Prosper Obunikem Adogu3

1Department of Medical Microbiology and Parasitology, Faculty of Medicine, Nnamdi Azikiwe University Awka (Nnewi Campus), Nigeria
 2Department of Community Medicine and Primary Health Care, Faculty of Medicine, Nnamdi Azikiwe University, Awka (Nnewi Campus), Nigeria
 3Department of Community Medicine, Faculty of Medicine, Nnamdi Azikiwe University Awka, (Nnewi Campus), Nigeria
*Corresponding Author: Ngozichukwu Gertrude Uzoewulu, Department of Medical Microbiology and Parasitology, Faculty of Medicine, Nnamdi Azikiwe University, Awka (Nnewi Campus), Nigeria.
Received: June 08, 2021; Published:July 27, 2021



Background: Nigeria has one of the highest burdens for TB, TB/HIV and multi-drug resistant TB in the world. Accurate and prompt identification of Mycobacterium tuberculosis for treatment of tuberculosis disease is essential to reducing the global burden. This study aimed at determining the sensitivity, specificity and other measures of diagnostic accuracy of direct smear microscopy using culture as the reference standard.

Methods: This was a cross-sectional study of presumptive tuberculosis patients who presented to selected hospitals in Anambra state, South-eastern Nigeria. A total of 550 sputum samples were assessed for Mycobacterium tuberculosis using direct smear microscopy by Ziehl-Nelson staining technique and culture by Lowenstein-Jensen solid medium, as diagnostic reference standard.

Results: Tubercle bacilli was detected by direct smear microscopy in 160 sputum samples (29.1%) whereas sputum culture was positive for Mycobacterium tuberculosis in 180 samples (32.7%). Out of 180 sputum culture positive TB patients, 34 patients (18.9%) were positive for human immunodeficiency virus in contrast to only 20 (12.5%) detected by direct smear microscopy. Diagnostic accuracy of direct smear microscopy was 82.2% (95% CL 77.8% - 87.5%). Specificity, 78.9% (95% CL 69.8% - 84.9%) was low compared to culture; sensitivity 88.9%, false positive rate 21.1% and false negative rate 11.1%.

Conclusion: To improve accuracy of TB case detection, culture should be used routinely as a backup to enhance the specificity of direct smear microscopy especially in HIV-positive patients.

Keywords: Tuberculosis; Mycobacterium tuberculosis; Direct Smear Microscopy; Sputum Culture; Anambra State

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Ngozichukwu Gertrude Uzoewulu., et al. "Understanding the Role of TAMs and Microenvironment in Lung Cancer Development". EC Pulmonology and Respiratory Medicine  10.8 (2021): 03-13.

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