I'm working on a form with about 30 input fields as part of a medical application. It allows the user to register patient data. 8 out of 30 fields are required, so our users are literally trying to find the required fields. These fields are indicated by an asterisk and are displayed scattered across the form. The form is logically grouped by categories (personal details, address, insurance, general practitioner, etc.)
Below I have 3 options. Unfortunately I cannot upload the whole form, but imagine the total form as having 6 of these blocks.
Option 1: Asterisk at end of input field
Option 2: Asterisk before the input field
Option 3: Asterisk before label
What is the best place for these asterisks to allow users to speed up their scan for required fields?