I think you better take TOEFL for applying business schools in top US schools. I had asked the admission administrators. Most of them told me that TOEFL is generally not waived if the primary language in his/her own country is not English or the medium of instruction during university study is not English as their own country.
Some schools in UK may waive TOEFL like LBS if you graduated from HKU since HKU is the partnership schools with LBS. Otherwise, you most likely is required to take TOEFL.