TABLE 3.

Tentative breakpoints and ranges of presumptive critical concentrations for AST in liquid and on solid media (phase II)

Drug	Range of critical concn or critical concna
	In BACTEC 460	On Middlebrook 7H10 agar
Capreomycin	1.25–2.5	10
Cycloserine	75–100	30
Ethionamide	1.25–2.5	5
Kanamycin	2.5–5.0	5
Amikacin	0.5–1.0	2.0–4.0
Clofazimine	0.125–0.25	0.5–1.0
Ofloxacin	1.0–2.0	1.0–2.0
Rifabutin	0.5–1.0	0.5–1.0

^aSingle values indicate previously established critical concentrations (20).