The culture of Mycobacterium sputum takes a long time, with solid media, commonly known as slow culture, taking 8 weeks to issue a negative report, while for liquid media, commonly known as fast culture, it takes 6 weeks to issue a negative report. Positive results are issued as soon as they appear, and for solid media, a positive result report may come out in about 2-4 weeks, while for liquid media, it may come out in about 1-2 weeks. This is determined by the genetic properties of Mycobacterium, which grows more slowly and therefore takes longer. If the results of Mycobacterium culture alone are done, a negative report may be available in 6 or 8 weeks, but for clinicians, who need to determine whether it is tuberculosis or non-tuberculous mycobacterial lung disease, further strain identification is required, and the time required may be increased by 4 weeks. If it is a non-tuberculous mycobacterial infection, further strain identification is required, which will take longer, so in fact 6 or 8 weeks is the time to inform the clinician of a positive or negative mycobacterial culture result, and the clinician will be billed further when further identification is required, which may take longer.