Killer Cells

Starlight • Expecting a miracle baby after a long road!
I saw another post about this (but haven't gotten any responses, so I'm making a new post). Who should be tested for Killer Cells? Anyone with autoimmune diseases?  And the only after recurrent miscarriages or failed IVFs? Or would over a year of not being able to conceive be enough. 
I'm preparing for my first IVF and want to be sure my body is ready. 
But do you have to go to a Reproductive  Immunologist? Or can your RE or GP order the tests?
Thank you!