Where can I go for a venous blood gas?

Age: 25, approximate height & weight: 5'4 110 lbs, gender: F, medications you take: None, smoking status: Non-smoker

previous and current medical issues: shortness of breath, persistent low CO2

duration and location of complaint: a few months to a year

I have been calling outpatient labs to see if they perform a VBG but no luck so far. Is this something I'd have to be inpatient for? Are there vascular centers or any other kind of practice that performs this?

Thank you!