CPT code 99391 is an Evaluation and Management (E/M) code for a preventive medicine service for a new patient, aged 0 to 1 year old. This code is used for the initial comprehensive visit to establish a baseline for the patient's health.
According to Medicare guidelines, this code can only be billed once per patient per 12-month period. However, private insurers and Medicaid may have their own specific policies regarding the frequency of billing for this code. It is important for healthcare providers to review their payer contracts and guidelines to ensure that they are billing correctly and within the allowed frequency limits for each patient.