Preferred Specimen(s) 2.0 mL sputum, BAL , Bronchi Wash, urine, pleural fluid;1.0 mL CSF
Transport Container
Sputum: collect in a sputum collection kit or a sterile, plastic container with a leak-proof cap.
BAL, Bronchi Wash, pleural fluid, CSF and Urine: Collect in a sterile, plastic container with a leak-proof cap.
Whole Blood or bone marrow: Collect in sterile tubes with EDTA as an anticoagulant.
Transport Temperature
- Refrigerated 5 days,
- -20oC for extracted DNA 30 days
Reject Criteria
- Specimens containing heparin
- specimens with calcium alginate swabs;
- Samples from leaking, uncapped or broken containers;
- quantity not sufficient specimens;
- Specimens exceeding stability.
Methodology Real Time PCR
Clinical Significance Tuberculosis is a widespread disease, with over 20,000 new cases being reported annually in the United States, in addition to the over 10 million people already infected. Although presumptive diagnosis of tuberculosis can be made on the basis of patient histories, clinical and radiological findings, and the presence of acid-fast bacilli in patient specimens, the isolation of the etiologic agent is required for the definitive diagnosis of tuberculosis. Disease in humans is caused by both M. tuberculosis and M. bovis, which are members of the M. tuberculosis complex (which also includes M. africanum, M.microti, and M. canettii). The most significant route of infection is via a respiratory route, generally resulting in pulmonary tuberculosis. Extra-pulmonary disease can occur following dissemination of the organism, and it may manifest itself as abdominal, CNS, joint, or bone disease (among others). Because of the morbidity associated with disease and the possibility for the spread of this disease, a rapid clinical diagnosis is required. Although presumptive diagnosis of tuberculosis can be made on the basis of patient histories, clinical and radiological findings, and the presence of acid-fast bacilli in patient specimens, the isolation of Mycobacterium tuberculosis is required for the definitive diagnosis of tuberculosis. Routine cultures are cumbersome and time-consuming. For that reason, the development of a more rapid method for diagnosis is highly desirable. PCR amplification and detection of Mycobacterial DNA has proved to be such a method. It is highly specific, and sensitivity can be greater than that of culture, which is considered to be the gold standard. A negative PCR indicates the absence of M. tuberculosis DNA in the sample tested, and it does not exclude the diagnosis of M. tuberculosis related diseases.
If culture is positive, identification will be performed.