The correct code for this is 94664, demonstration and/or evaluation of patient utilization of an aerosol generator, nebulizer, metered dose inhaler or IPPB device. This service is often provided incident-to the physician's E/M service. The Medicaid NCCI manual instructs the following about this code. "9. CPT code 94640 (pressurized or non-pressurized inhalation treatment for acute airway obstruction...) and CPT code 94664 (demonstration and/or evaluation of patient utilization of an aerosol generator...) generally should not be reported for the same patient encounter. The demonstration and/or evaluation described by CPT code 94664 is included in CPT code 94640 if it utilizes the same device (e.g., aerosol generator) that is used in the performance of CPT code 94640. If performed at separate patient encounters on the same date of service, the two services may be reported separately."can anyone tell me if I can bill separately for educating a patient on how to use the spacer on a metered dose inhaler?