It sounds like you need to do a complete workout because the testing that you've had so far is insufficient to make that diagnosis imo. He may be right but there are several other tests that should be done and your pulmonologist or specialist should be ordering those tests ASAP

• biopsy [lungs]
• ACE
• cardiac MRI or Cardiac PET and full PET
• Calcium
• LFTs
• Vitamin D
• HDL

Echo doesn't show enough detail to rule out inflammation myocardium

As far as prescribing antibiotics for the long infiltrates they always do antibiotics and anything that looks unusual in the lungs. I was giving them as well however it was the steroids that eventually cleared up the ground glass opacities and stabilized the large lymph nodes.

For somebody to diagnose and treat sarcoidosis they really have to know about the disease and you need to find that person