TABLE 1.

Interpretation of the mCIM and eCIM results^a

Test	Zone size	Interpretation
mCIM	≥19 mm	Negative
	16–18 mmc	Indeterminate
	6–15 mmd	Positive
eCIMb	≤4-mm increase in zone size (compared to mCIM zone size)	Negative
	≥5-mm increase in zone size (compared to mCIM zone size)	Positive

^aeCIM, EDTA-modified carbapenem inactivation method; mCIM, modified carbapenem inactivation method.

^bThe eCIM is only interpreted when the mCIM result is positive. In contrast to the mCIM, when the eCIM result is interpreted pinpoint colonies within the zone of growth inhibition around the meropenem disk incubated in the presence of EDTA should be ignored.

^cAn indeterminate mCIM result occurs when the zone size is 16 to 18 mm, when the zone size is ≥19 mm with pinpoint colonies in the zone of growth inhibition, or when carbapenemase production cannot be confirmed.

^dA zone size of 16 to 18 mm with pinpoint colonies in the zone of growth inhibition is also considered a positive mCIM result.