Doctors taking commission from diagnostic centers

Nowadays, many huge companies, diagnostic centers and many big hospitals give their letterheads to the doctors.  Whenever the doctors have to perform tests on their patients, they write the tests on their letterheads and the patients go to those centers and get their tests.  The doctors are given a huge commission or percentage on that.  Is this commission permissible for them?

If the intention of using the letterheads of other hospitals/centers is not of earning commission, but only because those hospitals, etc. are dependable and reliable and those hospitals also give commission to the doctor and also if patients get their tests, etc. done in some other reliable diagnostic centers, the doctor accepts those reports, then that commission is permissible.  

If the doctors do not accept the reports of other reliable diagnostic centers and insist on going to only one diagnostic center, then in this case, this commission comes under the category of bribe, accepting this commission is not permissible.  As given in Fatawa A'alamgiri, Kitab Adab Ul Qadhi.  

And Allah (Subhanahu Wa Ta'ala) knows best.

Mufti Hafidh Syed Ziauddin Naqshbandi Qadri

[Professor, Islamic Law, Jamia Nizamia,
Founder-Director Abul Hasanaat Islamic Research Center]