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Mycobacterial culture

  • Definition
    • Mycobacterial culture is a test to look for the bacteria that cause tuberculosis and similar infections.

  • Alternative Names
    • Culture - mycobacterial

  • How the Test is Performed
    • A sample of body fluid or tissue is needed. This sample may be taken from the lungs, liver, or bone marrow.

      Most often, a sputum sample will be taken. To obtain a sample, you will be asked to cough deeply and spit out the material that comes up from your lungs.

      A biopsy or aspiration may also be done.

      The sample is sent to a laboratory. There it is placed in a special dish (culture). It is then watched for up to 6 weeks to see if the bacteria grow.

  • How to Prepare for the Test
    • Preparation depends on how the test is done. Follow your health care provider's instructions.

  • How the Test will Feel
    • How the test will feel depends on the specific procedure. Your health care provider can discuss this with you before the test.

  • Why the Test is Performed
    • Your doctor may order this test if you have signs of tuberculosis or a related infection.

  • Normal Results
    • If there is no disease present, there will be no growth of bacteria in the culture medium.

  • What Abnormal Results Mean
    • Mycobacterium tuberculosis or similar bacteria is present in the culture.

  • Risks
    • Risks depend on the specific biopsy or aspiration being performed.

  • References
    • Chernecky CC, Berger BJ. Culture - routine. In: Chernecky CC, Berger BJ, eds. Laboratory Tests and Diagnostic Procedures. 6th ed. Philadelphia, PA: Elsevier; 2013:409-411.

      Fitzgerald DW, Sterling TR, Haas DW. Mycobacterium tuberculosis. In: Bennett JE, Dolin R, Blaser MJ, eds. Mandell, Douglas, and Bennett's Principles and Practice of Infectious Diseases. 8th ed. Philadelphia, PA: Elsevier Saunders; 2015:chap 251.