ISSN: 2577-4379
Authors: Desta KT*, Dolamo BL and Endris IH
Background: Even though the laboratory testing is essential for the diagnosis and control of tuberculosis (TB), it does not receive enough attention in Ethiopia where acid-fast bacilli (AFB) sputum microscopy is often the only available method to diagnose TB. The low detection rate of Mycobacterium tuberculosis in Ethiopia using sputum microscopy and the limitation of chest-x-ray for mass screening and diagnosis initiated the researchers to conduct the study. Objective: The objective of this study was to make a comparative analysis of chest x- ray, sputum microscopy and culture for diagnosis of Mycobacterium tuberculosis. Methods: Quantitative, retrospective cross-sectional study was conducted to analyses chest x-ray, sputum microscopy and culture for diagnosis of Mycobacterium tuberculosis. The study was conducted on data collected from International Clinical Laboratories (ICL) in Ethiopia. Samples were selected from the logbooks using systemic random sampling and until the required sample number of 943 had been obtained. Data collection was done using standardized checklist from 943 participants’ documents from February 2010 to March 2011. The 943 study participants’ documents sampled were analyzed for x-ray, AFB microscopy, solid culture, liquid culture and anti-TB drug susceptibility testing. Results: Among the 943 study participants’ documents with suggestive chest x-ray findings; 13(1.4 %) had a positive smear results for AFB. The total number of organisms recovered was 98 of which 23 were M. tuberculosis whereas 75 were non-tuberculosis mycobacterium (NTM). In this study significant difference was not demonstrated statically between BACTEC Mycobacterium growth indicator tube (MGIT) 960 liquid medium and Lowenstein Jensen (LJ) solid medium in terms of Mycobacterial recovery rate (p>0.05). The diagnostic value of AFB sputum microscopy against sputum culture method for diagnosis of tuberculosis in terms of sensitivity, specificity, and positive and negative predictive values of serial AFB screening among these groups were 26%, 99.2%, 46%, and 98.2% respectively. The resistance patter to isoniazid; rifampin, ethambutol and streptomycin was 30.5%), 8%, 26% and 22% respectively. 2.1% participants' documents were found to be multidrug resistant (MDR).Conclusion: The findings of this study revealed that chest x-ray for TB screening lacks significant specificity and is susceptible to miss screening and diagnosis. The findings of this study also showed that culture method has a great potential to improve the clinicians’ ability to diagnose TB.
Keywords: TB; Chest X-Ray; Culture; MDR; Sputum Microscopy; AFB; TB-Registers
