EHR is a comprehensive medical and cross-institutional record or similar documentation of the past and present physical and mental state of health of an individual in electronic form. EHRs also provide for ready availability of these data for medical treatment and other closely related purposes. EHRs are real-time, patient-centred records that provide immediate and secure information to authorized users. EHRs typically contain a patients medical history, diagnoses and treatment, medications, allergies, immunizations, as well as radiology images and laboratory results. A National EHR system is most-often implemented under the responsibility of a national health authority and will typically make a patients medical history available to health professionals in health care institutions and provide linkages to related services such as pharmacies, laboratories, specialists, and emergency and medical imaging facilities (epSOS definition).