Mycobacterial culture

Definition

Mycobacterial culture is a test to look for the bacteria that cause tuberculosis and other infections caused by similar bacteria.

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 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. St Louis, MO: Elsevier Saunders; 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, Updated Edition. 8th ed. Philadelphia, PA: Elsevier Saunders; 2015:chap 251.