Arslan Ahmed Salam, Sana Rehman, Muhammad Kashif Munir, Rizwan Iqbal, Saqib Saeed Saeed, Saulat Ullah Khan.
Importance of ziehl-neelsen smear and culture on lowenstein jensen medium in diagnosis of pulmonary tuberculosis.
Pak J Chest Med Jan ;20(2):57-61.

Background: Ziehl-Neelsen (ZN) smear is widely used for rapid diagnosis of Tuberculosis in developing countries but culture on Lowenstein Jensen (LJ) medium is more sensitive and cheaper than modern diagnostic techniques in the present settings. Objective: To evaluate the validity of ZN smear and reliability of acid-fast bacilli culture on LJ medium. Design and Settings: This comparative study was carried out in PMRC TB Research center in collaboration with Institute of Chest Medicine King Edward Medical University, Mayo Hospital Lahore from January, 2009 to December, 2011. Patients and methods: Study subjects included patients visiting TB OPD clinic and wards of Mayo Hospital. Lahore and other leading hospitals of Lahore. A total of 8102 specimen were processed for both smear and culture. The smears were stained with ZN method using 1% carbolfuchsin, 25% sulphuric acid and 0.3% methylene blue and were observed under 100-x oil immersion lens. Cultures were inoculated on LJ medium after digestion and decontamination of clinical specimens. Results: Of total 7333 study subjects, 7055 were pulmonary specimens and among them 800 (11.33%) were smear positive while 1092 (15.47%) were culture positive. Out of 800 smear positive pulmonary tuberculosis cases 664 (83%) were found to be positive on LJ culture. A total of 428 (6.06%) pulmonary cases were negative on the smear but were found to be positive on LJ culture for Mycobacterium tuberculosis. Conclusion: Although AFB smear is rapid, cheap and specific test for early diagnosis of TB but its sensitivity is low and culture on LJ medium is still thought to be gold standard although takes longer time to grow and provides us with positive growth to do drug sensitivity testing.

PakMediNet -Pakistan's largest Database of Pakistani Medical Journals - http://www.pakmedinet.com