A way of assessing whether a beta-lactamase is affected by an inhibitor. This helps identify the type of beta-lactamase. For each test, separate disks containing the antibiotic tested alone and in combination with an inhibitor are applied to the inoculated agar. The inhibition zone around the disk with the test antibiotic alone is compared with the zone around the test disk combined with the inhibitor. Sets of disks are commercially available to do this type of testing.