Physician

Shannon E O'Mahar, MD

According to 2025 Medicare claims, Shannon O'Mahar, MD (NPI: 1366569899) practices hematology/oncology in the Janesville-Beloit, WI market, with the plurality of this provider's patient population coming from Rock, WI. This provider's primary affiliated billing organization is DEAN HEALTH SYSTEMS, INC (NPI: 1053358846; TIN: 391128616) and primary practice location at 53546-2343. O'Mahar is affiliated with the SSM WI ACO LLC (ACO ID: A5124), participating under the MSSP model.

O'Mahar's data goes back to 2015 and runs through 2024. For example, in 2024, this provider had 491 traditional Medicare patients, billed 103,230 HCPCS/CPT codes, and received $2,462,913 in Medicare payments. The top billing code was 99214 (Established patient office or other outpatient visit with moderate level of decision making, if using time, 30 minutes or more). Part D data shows 2,751 prescription claims across 324 beneficiaries totaling $12,673,620 in drug costs, led by Revlimid (Lenalidomide). 2023 DME data shows 22 claims. Open Payments data shows 2 records totaling $80,854. You can download detailed data with all billing codes (2015-2024). For more recent data, please contact us.

Over the past 10 years, this provider's Medicare Part B carrier billing has moved from a lower plateau to a higher plateau, from $527,405 to $2,462,913. Similarly, Part D prescription costs have moved sharply higher in recent years, from $801,213 to $12,673,620. In contrast, DME billing represents a smaller volume and started with an early spike, then settled into a lower baseline, moving from $4,100 to $1,544.

Part B Carrier Billing Trend

Medicare payment trend, with N of patients and claim lines in the table.

Year	Patients	Clm Lines	Payment
2015	380	36,612	$527,405
2016	395	56,087	$988,836
2017	409	69,524	$1,386,743
2018	398	69,824	$1,108,284
2019	391	97,018	$1,886,000
2020	400	104,790	$1,833,062
2021	425	108,510	$1,829,381
2022	468	113,925	$2,312,759
2023	482	110,049	$2,015,795
2024	491	103,230	$2,462,913

Part D Events Trend

Drug cost trend, with N of patients and prescription claims in the table.

Year	Patients	Claims	Drug Cost
2015	157	898	$801,213
2016	186	920	$975,700
2017	194	1,379	$2,050,396
2018	192	1,446	$3,261,894
2019	223	1,663	$4,297,118
2020	250	1,989	$7,604,229
2021	271	2,310	$9,977,529
2022	312	2,728	$10,736,150
2023	324	2,738	$11,506,043
2024	324	2,751	$12,673,620

DME Billing Trend

Medicare payment trend, with N of patients and DME claim records in the table.

Year	Patients	Claims	Payment
2015	N/R	69	$20,114
2016	N/R	38	$250
2017	N/R	70	$4,088
2018	N/R	N/R	N/R
2019	N/R	31	$2,541
2020	N/R	40	$2,417
2021	N/R	47	$25,408
2022	N/R	60	$1,760
2023	N/R	22	$1,339
2024	N/R	N/R	N/R

* / # = suppressed by CMS; 0 = reported zero; N/R = not reported or blank.

Top 5 Part B carrier billing codes in 2024

By total payments.

Code	Description	Patients	Clm Lines	Total Payment
99214	Established patient office or other outpatient visit with moderate level of decision making, if using time, 30 minutes or more	179	383	$87
99213	Established patient office or other outpatient visit with low level od decision making, if using time, 20 minutes or more	294	639	$60
80053	Blood test, comprehensive group of blood chemicals	79	353	$10
36415	Insertion of needle into vein for collection of blood sample	164	622	$9
85025	Complete blood cell count (red cells, white blood cell, platelets), automated test and automated differential white blood cell count	138	661	$8

Top 5 Part D drugs in 2024

By total drug costs.

Drug	Generic	Claims	Total Day Supply	Total Drug Cost
Revlimid	Lenalidomide	217	6,062	$3,918,240
Pomalyst	Pomalidomide	98	2,721	$2,228,140
Brukinsa	Zanubrutinib	58	1,740	$765,279
Imbruvica	Ibrutinib	32	896	$485,953
Jakafi	Ruxolitinib Phosphate	30	900	$474,081

Top 5 DME services in 2024

No connected or detailed DME service-level records for 2024.

Open Payments Summary in 2024

Category	Definition	Records	Total Reported Amount	Top Related Entity
General Payments	Reported payment or transfer-of-value amount.	1	$19	Novartis Pharmaceuticals Corporation
Research Payments	Reported research-related payment or transfer-of-value amount.	1	$80,835	Novartis Pharmaceuticals Corporation
Ownership / Investment Interests	Reported value of ownership or investment interests.	0	$0	N/R

Explore More Providers

FAQ

What Medicare data is available for Shannon E. O'Mahar, MD?

Tedicare shows public-source Medicare data for Shannon E. O'Mahar, MD (NPI 1366569899), including provider identity, specialty, market context, Medicare Part B activity, Part D prescribing, DME records, Open Payments where available, billing organization details, and ACO affiliation signals where available. Profile data covers 2015-2024, with current attribution based on 2025 claims where available.

Does Shannon E. O'Mahar, MD have ACO affiliation data?

Shannon E. O'Mahar, MD is shown with ACO affiliation data for SSM WI ACO LLC (MSSP, ACO ID A5124).

What billing organization is linked to Shannon E. O'Mahar, MD?

Shannon E. O'Mahar, MD is linked to DEAN HEALTH SYSTEMS, INC (billing NPI 1053358846) in the available physician profile data.

Does Shannon E. O'Mahar, MD have Open Payments data?

Shannon E. O'Mahar, MD has 2 connected Open Payments records in the available 2024 summary data.

Can I download physician-level Medicare data from Tedicare?

Yes. Tedicare provides sample physician export data and paid custom physician data exports for research, planning, outreach, and market analysis. Exports can include physician profile fields, market and specialty context, billing organization details, ACO affiliation signals where available, and Medicare utilization data.