Vikas,
Doctors can monitor iron levels with simple serum ferritin or serum transferrin saturation tests. The most accurate test is a liver biopsy, but you want to avoid an invasive test like that unless it's absolutely necessary.
I'm repeatedly surprised at the variety of answers you'll hear from doctors about when to be concerned about iron buildup and when to start treatment. There seems to be no general consensus on how high is "too high".
You are welcome to read or post in the threads in the
Transfusions and Iron Overload forum or start your own thread if you like. For example, there's a thread named
Iron Overload and When to Start Treatment.