One or multiple beta-lactam test reagent(s) [e.g., a cephalosporin (nitrocefin, cefpodoxime) or beta-lactamase inhibitor (clavulanic acid)] in an impregnated disc, strip, or dehydrated in a microplate, intended to be used in microbial testing to detect beta-lactamase enzyme [e.g., extended-spectrum beta-lactamase (ESBL)] production by a microorganism isolated from a clinical specimen by culture.