Level 1 Data Flow Diagram for a hospital management system modeling four core processes: Patient Registration, Doctor Consultation, Laboratory Testing, and Billing System. Data flows from external entities (Patient, Doctor, Lab Technician) through processes that read and write to four data stores (Patient Records, Medical Records, Lab Reports, Billing Records). This DFD establishes the high-level workflow and data dependencies essential for designing a scalable, HIPAA-compliant AWS healthcare infrastructure. Fork this diagram on Diagrams.so to decompose processes further, add AWS services (RDS, S3, Lambda), or customize for your hospital's specific workflows. The optional lookup flows between data stores highlight cross-functional dependencies critical for system integration planning.