mLIMS has a special feature that allows you to generate your own dropdown lists as you go.
Whenever you see a field with the gray arrow on the right, that is a dropdown list that you can add to on the go. If your choice is not there, go ahead and type it in. It wil appear in the dropdown next time.
You can disallow users from generating dropdowns in the user permissions, and set the dropdwon menus in the system settings instead.