Each fall, CMS released data on the prior year's Part B CPT code utilization and payments both at the National and the State levels. CY2018 data has been released.
See national data here.
See state level data here.
The state data is actually by historical Medicare Part B carrier zones, so some states have two parts (e.g. NCalif and SCalif). Also, the Excel files are given cryptic contractor numbers and you need to decode with a provided PDF. (Noridian Contract 03102 = CMS Excel 03102 = Arizona).
Separately, and on a longer delay, CMS releases physician-level CPT code payments. These appear around June for the year 18 months earlier. Here.
For example, the CY2018 National data file #04 contains 80,000-series codes, and in CY2018 CMS Part B paid for 22,615 uses of 81162 (BRCA Seq + Dup Del) totaling $50,896,967.
If we turn to the CY2018 state data, we find that Utah is File #03502, where there are 12,459 uses of 81162 paying $28,069,254. (In 2018 in Utah, older BRCA code 81212 had only 496 uses for $28,240.) Research can be done at national and state levels for any code.
Example: FMI CDx Test
In national data, Code 0037U for Foundation Medicine FDA test was paid $33,396,800 (used 9,870 times). However, I believe this code was effective in April 2018, so this may reflect only FMI payments in three quarters of 2018. I believe there are 100,000-200,000 incident Medicare patients with advanced cancer (and multiples of that number as prevalent patients), so the FMI tests was not used in too many of them in CY2018, despite the NCD becoming effective in March 2018.
0047U is the Genomic Health prostate panel, which tallied 1,277 uses for about $4M in 2018.
Payments for all the other PLA codes 0U-70U were only about 4M more than payments for 0037U and 0047U. Many had 0 CMS payments.