Below are the key features and modules that can be used to build a hospital management ERP system in Odoo:

1. Patient Management:

• Create and manage patient records.
• Maintain patient demographics, medical history, and contact information.
• Assign unique identifiers and medical record numbers.

2. Appointment Scheduling:

• Schedule patient appointments with doctors and other healthcare providers.
• Manage appointment calendars.
• Send appointment reminders to patients.

3. Electronic Health Records (EHR):

• Store and manage electronic health records for patients.
• Record diagnoses, treatments, and medical history.
• Enable secure access to patient records by authorized healthcare personnel.

4. Billing and Invoicing:

• Generate invoices for medical services and treatments.
• Manage insurance claims and billing.
• Handle patient payments and payment tracking.

5. Inventory Management:

• Track medical supplies, medications, and equipment.
• Manage stock levels and reorder supplies as needed.
• Ensure compliance with regulatory requirements for pharmaceuticals and medical devices.

6. Pharmacy Management:

• Manage the hospital pharmacy, including inventory and prescriptions.
• Dispense medications to patients.
• Track medication usage and patient history.

7. Laboratory Information System (LIS):

• Manage laboratory tests and results.
• Track specimen samples.
• Generate and deliver test reports to healthcare providers and patients.

8. Radiology Information System (RIS):

• Manage radiology and imaging services.
• Schedule and track radiology appointments.
• Store and retrieve medical images and reports.

9. Human Resources and Payroll:

• Manage hospital staff and their employment details.
• Handle payroll processing for healthcare personnel.

10. Accounting:

• Financial management and reporting for the hospital.
• Expense tracking and budgeting.

11. Pharmacy Inventory:

• Manage pharmaceutical inventory and prescriptions. 
• Track medication dispensing and stock levels.

12. Quality Control:

• Implement quality control checks and audits. 
• Ensure compliance with healthcare standards and regulations.

13. Reporting and Analytics:

• Generate custom reports and dashboards for hospital management. 
• Analyze patient outcomes and operational performance.

14. Mobile Access:

• Allow healthcare professionals to access patient records and schedules on mobile devices.

15. Customization and Integration:  

• Customize Odoo to meet specific hospital requirements. 
• Integrate with diagnostic equipment and other healthcare systems.

Please note that building a complete hospital management ERP system in Odoo would require significant customization and configuration. It's essential to work with Odoo implementation experts or developers who have experience in healthcare management systems to ensure that the solution meets regulatory compliance and the unique needs of the hospital or healthcare institution. Additionally, since software evolves, it's a good idea to check the latest Odoo features and modules to see if there have been any updates or new functionalities introduced in more recent versions.