Inpatient Only Procedure (Clinical Trial) provided as an Outpatient Service - Will Medicare pay for anything?

Hi- I need help on this.

I've searched CMS regs and everything is so vague. I know that Medicare does not pay for 'IP Only Procedures' provided as outpatient services. So I can't bill this on bill type 111.

Can Medicare be billed for any ancillary charges on an outpatient claim? Lab, Ekg? If any services could be billed, would Condition Code D4 & registry number need to be  reported along with Q0 Modifier to note clinical trial service?

Should treatment of the patient at least be reported to Medicare even though reimbursement is not expected? I know Medicare requires 'inpatient no pay' claims when patient has exhausted medicare days or outpatient services reported with a GA Modifier when provider does not expect Medicare reimbursement.
Basically, can I bill for anything? if not, does the service need to be reported?

Thanks for any assistance