The
method includes the use of Mueller–Hinton agar without supplements for non-fastidious organisms and with 5% mechanically defibrinated
horse blood and 20 mg/Lb-NAD for fastidious organisms, a standardized inoculum resulting in confluent growth, an incubation time of 16–
20 h, a reading guide on how to read zone diameters on individual species-agent combinations and zone diameter breakpoints calibrated to
the EUCAST clinical MIC breakpoints. EUCAST recommendations are described in detail and updated regularly on the EUCAST website