14.1.3 TB culture from sputum
A culture involves growing the bacteria in the laboratory; this test can only be ordered by a doctor or a clinician.
Culturing of TB bacteria from a sputum sample in the laboratory is very expensive and takes several weeks to produce a result; however it is a very sensitive and highly specific tool. It plays a key role in identifying the type of drug-resistant TB found in a patient, such as those patients who are not responding to treatment as well as expected. Culture with Drug Sensitivity Testing (DST will be covered in Study Session 16) takes even longer; but provides crucial information about which antibiotics will kill the bacteria isolated from the patient. You should send patients for TB culture and DST if they are suspected of drug-resistance.