CMS releases copious data on Part B provider billing, including lab and all other CPT based services. However, CMS doesn't release the same granularity of billing for Hospital outreach lab services. However, there's a way to impute the hospital billing relative to the Pt B independent lab billing.
Here's the trick. For the past 3 years, OIG has released an annual report of all payments on the CLFS (whether to hospital labs or independent labs.) The October 2017 version, showing CY2016 data, is here. In particular, OIG provides a table of all CLFS payments for the top 25 CPT codes in its report.
On a separate website, about the same time, CMS released all the Part B (independent lab) payments by CPT code. That's here. CMS and OIG don't do this for us, but in a few minutes you can list the OIG payment data (A+B) and the Pt B data (B), and subtract the difference to get the "A" or hospital reference lab payments, by CMS, on the CLFS. The data here:
|click to enlarge; dollars in Millions; see notes|
You'll quickly note that hospital CLFS payments are generally about 30% of all CMS CLFS payments by dollar volume. It does vary by code. Note that G-code drug panels are almost entirely Pt B independent labs. Note too, that hospitals don't bill Cologuard or Oncotype DX (81528, 81519).
There's not that much grand variation in most of the other 25 codes. CBC and chem panels are almost half dollar volume at hospital labs (85027, 80048). PSA and Folic acid are not so common in hospital labs (23%).
Remember that these data would have looked very different before 2014 or so, when CMS stopped paying for hospital clinic outpatient lab tests separately.[*] The data above for 2016 would be for hospital reference lab CLFS tests that are not clinical outpatients.
[*] Except for genetic/genomic tests, which are still paid separately. Outpatient clin chem was bundled into fees that support outpatient visits or procedures.