BIG-IP : monitor examines http status code

Yes, you can do this with an HTTP monitor. Some specifics are here:

http://support.f5.com/kb/en-us/solutions/public/2000/100/sol2167.html

You'll want to tailor your receive string to match what the server will respond with if it's healthy. For example, HTTP/1.1 200 OK could be your receive string