Comparison of a Novel, Rapid Chromogenic Biochemical Assay, the Carba NP Test, with the Modified Hodge Test for Detection of Carbapenemase-Producing Gram-Negative Bacilli

We compared carbapenemase detection among 271 Gram-negative bacilli (of which 131 were carbapenemase producers) using a novel chromogenic rapid test-the Carba NP test (CNP)-and the modified Hodge test (MHT). Sensitivities were comparable (CNP, 100%, versus MHT, 98%; P = 0.08), but CNP was more specific (100% versus 80%; P < 0.0001) and faster.