I don't like to tell this to other physicians but the secret is Medicare's "Buy and Bill" and "White bagging" system. Thats what many oncology and other (MS) practices do. I found this out after i investigated a practice that was making insane amounts of money and doing shady stuff.
In short, you have a contract with a drug company/pharamacy who will sell you the drug for a steep discount (because you will prescribe a lot of it) and you keep it in your in-house pharmacy. Then you administer it to patients and get full reimbursement rates from Medicare and an additional 6% for infusion.
So if a drugs average cost is $10k, the company will sell it to you for $8k and medicare will reimburse $10k plus $600 infusion charge. Plus there are some other minor charges for facility and your regular visit charge. So you are making over $3000 on that one infusion. For some drugs like Lemtrada- the insurance price is over $80k/year. So depending on your contract with the company, you are looking at 10-15k or more per patient. In addition to regular billing.
In addition, many MS centers have their own PT/OT/ST services and MRI/EEG/EMG(which they read themselves). They do some pain management and Botox/baclofen as well.
Please DONT get any ideas and do this.