Standard Diagnostic Procedure for Tuberculosis: A Review

Abstract

Despite continuous effort in monitoring and treatment of tuberculosis, the disease remains a major public health issue. Rapid diagnosis and appropriate therapies become the first priorities in controlling the growing epidemics. The bedside decision on the initiation of anti-tuberculous drug therapy are based on epidemiologic, clinical, radiolographic, and/or histological findings, which can generally be supported by a rapid microbiologic test, commonly a positive acid-fast bacilli (AFB) smear result. However, AFB smear is positive in only half of patients with subsequently culture positive for Mycobacterium tuberculosis. Although the sensitivity of the smear is improved by fluorescent staining, the test fails to distinguish between tuberculous and nontuberculous mycobacteria. Diagnosis of Tuberculosis (TB) is mainly based on the culture method and non-culture methods. Molecular techniques are becoming more advanced and confirmatory diagnostic procedure of TB. Recent surveys also reveal that drug-resistant tuberculosis is still ubiquitous and alarmingly high in several countries. The situation is further complicated by the emergence of multi-drug resistant tuberculosis (MDR-TB). MDR-TB results from improper administration of antibiotics in chemotherapies of TB patients and is recognised as Mycobacterium tuberculosis resistant to at least isoniazid (INH) and rifampin (RIF), the two most common first-line antituberculosis drugs. 

Keywords: Tuberculosis, AFB smear, Multi Drug Resistant (MDR), LJ medium