Due, in part, to the unavailability of methicillin in the United States, cefoxitin has replaced methicillin for disk diffusion tests, which determine the sensitivity of a bacterial specimen to a given antibiotic. Cefoxitin also yields more accurate results for disk diffusion tests. Interpretive criteria for determining susceptibility to cefoxitin via disk diffusion are greater than or equal to 22mm resulting in a "susceptible" result for "Staphylococcus aureus" and greater than or equal to 25mm for coagulase-negative staphylococci to be considered susceptible.