How do you know if your child has high IQ (100+) at the age of 5 yrs?

If you realize your kid is exceptionally bright e.g. in terms of knowledge, reading extremely well, fidgeting a lot in class and find it boring and etc., you can let your child to go for IQ test. You can bring your child to NUH/KKH for the test, which will be cheaper compared to private one.