Dr. Shannon E. O'Mahar, MD
- Medicare services, 2024
- 48,714
- Medicare patients, 2024
- 491
- Part D claims, 2024
- 2,751
- Publications
- 1
- Hospital affiliations
- 5
- Practice address
- 1211 Fish Hatchery Rd, Madison, WI 53715
- Practice phone
- Call (608) 250-1560
- Professional email
- Get professional email
- Personal email
- Get personal email
- Mobile number
- Get mobile number
Primary practice
Imaging Services at SSM Health Dean Medical Group (Fish Hatchery Rd)
Mammography / Breast Imaging Center · Madison, Wisconsin
Find Dr. O'Mahar's professional email, personal email and mobile number
Dmand AI checks each channel through healthcare-specific waterfall enrichment. See what is on file with a free account, with practice phones, licenses and affiliations.
Dr. Shannon E. O'Mahar is a hematologist and oncologist in Madison, Wisconsin
Dr. O'Mahar practices at Imaging Services at SSM Health Dean Medical Group (Fish Hatchery Rd) in Madison, Wisconsin.
Dr. O'Mahar's NPI, 1366569899, was assigned on March 22, 2007. Dr. O'Mahar holds Wisconsin license 52434-020.
- NPI
- 1366569899NPI Registry (opens in a new tab)
- Medicare PAC ID
- 7517028244
- NPI enumeration date
- March 22, 2007
- NPI status
- Active
- Accepts Medicare assignment
- Yes
- Offers telehealth
- Yes
- Practice phone
- (608) 250-1560
- Professional email
- Get email
- Personal email
- Get email
- Mobile number
- Get number
- Sex
- Female
- Estimated age
- 47
- Medical school graduation
- 2005
Sources: NPPES NPI Registry (CMS); Dmand AI Professional Profile Data; Dmand AI Affiliation Data; and Doctors and Clinicians National Downloadable File (CMS)
Dr. Shannon E. O'Mahar practices at Imaging Services at SSM Health Dean Medical Group (Fish Hatchery Rd) in Madison, Wisconsin
Dr. O'Mahar's primary practice is Imaging Services at SSM Health Dean Medical Group (Fish Hatchery Rd), at 1211 Fish Hatchery Rd, Madison, WI 53715. The practice phone is (608) 250-1560.
- Imaging Services at SSM Health Dean Medical Group (Fish Hatchery Rd)1211 Fish Hatchery Rd, Madison, WI 53715Phone(608) 250-1560
Source: Dmand AI Affiliation Data
Dr. Shannon E. O'Mahar is affiliated with 7 sites of care and 1 medical group
Dr. O'Mahar's primary practice is Imaging Services at SSM Health Dean Medical Group (Fish Hatchery Rd) in Madison, Wisconsin. Dr. O'Mahar is also affiliated with SSM Health St. Mary's Hospital - Madison. The medical group on file is SSM Health Dean Medical Group. Dmand AI also links Dr. O'Mahar to 4 more hospitals and 1 group practice or clinic, each named with a free account. Dr. O'Mahar's employer is on file too: a breast imaging center.
Sources: Dmand AI Affiliation Data; and Dmand AI Org Hierarchy Data
Dmand AI tracks the EHR system at Dr. Shannon E. O'Mahar's practice
Dmand AI tracks the electronic health record (EHR) system at each site where Dr. O'Mahar practices, 7 sites in all. Vendor and product names are available with a free account.
| Site | EHR vendor and product |
|---|---|
| Imaging Services at SSM Health Dean Medical Group (Fish Hatchery Rd) | Available with a free account |
| +6 more affiliated sites | Available with a free account |
Source: Dmand AI Technology Install Data
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Dr. Shannon E. O'Mahar is one of 277 hematologists and oncologists in Wisconsin
Hematology and oncology is Dr. O'Mahar's primary specialty in the NPI Registry, under taxonomy code 207RH0003X. Dr. O'Mahar is licensed in Wisconsin.
Specialties and state licenses
- Hematology and oncology, WisconsinPrimary
Hematologists and oncologists near Dr. O'Mahar
Counts of hematologists and oncologists with a Dmand AI profile, by place and practice. Each opens the list.
Sources: NPPES NPI Registry (CMS); Dmand AI Professional Profile Data; and Dmand AI Peer Benchmarks
Dr. Shannon E. O'Mahar billed Medicare for 48,714 services in 2024
CMS data shows 48,714 Medicare services from Dr. O'Mahar across 30 procedure codes in 2024, for 491 Medicare patients. Medicare paid $1,774,355 for them.
Dr. O'Mahar's Medicare services by type, 2023 to 2024
- 2023
- 2024
- Drugs given in the office
- 2023: 29,3322024: 44,94853%
- Office and hospital visits
- 2023: 1,1522024: 1,1312%
- Lab and pathology
- 2023: 1,0642024: 1,0382%
- Tests and treatments
- 2023: 9222024: 9645%
- Surgery
- 2023: 6502024: 6224%
- Other services
- 2023: 132024: 1115%
Where Dr. O'Mahar's Medicare services took place, 2024
- In an office48,672100%
- In a facility420%
Dr. O'Mahar compared with the Wisconsin median for hematologists and oncologists, 2024
- Dr. O'Mahar
- Wisconsin median
- Medicare services
- 48,714vs 54589.4 times
- Medicare patients
- 491vs 1722.9 times
- Part D claims
- 2,399vs 4465.4 times
Medians across 269 hematologists and oncologists in Wisconsin with Dmand AI profiles that report each measure.
Dr. O'Mahar's most billed Medicare procedure codes, 2024
CMS publishes codes billed for 11 or more Medicare patients. Each label is the code family; CPT descriptions are licensed by the AMA.
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Medicare shows one payer. Book a meeting to get commercial claims data for Dr. O'Mahar and other hematologists and oncologists in Wisconsin.
Sources: Medicare Physician & Other Practitioners - by Provider and Service (CMS), 2024 data; and Dmand AI Peer Benchmarks
Dr. Shannon E. O'Mahar treated 491 Medicare patients in 2024, average age 74
CMS counts 491 Medicare patients who saw Dr. O'Mahar in 2024. The largest group is 65 to 74, with 233 patients. 69% of them have high cholesterol, and 68% have high blood pressure. 8% are also on Medicaid. Their average risk score is 1.81, where 1.00 is the Medicare average, so they are sicker than most Medicare patients.
Across all payers, Dmand AI patient panel data puts Dr. O'Mahar's median patient age at 76, with 57% women.
Dr. O'Mahar's Medicare patients by age, 2024
Dr. O'Mahar's Medicare patients by sex, 2024
- Women29861%
- Men19339%
Chronic conditions among Dr. O'Mahar's Medicare patients, 2024
- High cholesterol69%
- High blood pressure68%
- Cancer37%
- Arthritis34%
- Diabetes27%
- Chronic kidney disease25%
- Mood disorders25%
- Anxiety22%
Share of Medicare patients with each condition. A patient can have several.
Dr. O'Mahar's patients across all payers
Dmand AI patient panel data covers Medicare, Medicaid and commercial patients.
Patient panel by age, all payers
Median age 76
Patient panel by sex, all payers
- Women57%
- Men43%
Sources: Dmand AI Patient Panel Data; and Medicare Physician & Other Practitioners - by Provider (CMS), 2024 data
Dr. Shannon E. O'Mahar wrote 2,751 Medicare Part D claims in 2024
In 2024, Dr. O'Mahar wrote 2,751 Medicare Part D claims for 324 patients. 69% of them were for generic drugs. CMS names the drug for 2,399 of them, across 49 drugs with 11 or more claims each, at $11,181,785 in total drug cost. In 2023, CMS named 2,407 claims across 52 drugs.
Dr. O'Mahar's Part D claims by kind of drug, 2024
- Generic1,903 claims69%
- Brand-name848 claims31%
Dr. O'Mahar's most prescribed drugs by claims, 2024
CMS names a drug when it has 11 or more claims. Share is of the claims for drugs CMS names.
Drug classes CMS tracks in Dr. O'Mahar's Part D claims, 2024
- Opioids4%102 of 2,751 claims
- Antibiotics3%95 of 2,751 claims
- Antipsychotics, patients 65 and over0%11 of 2,751 claims
Share of all Part D claims for each drug class CMS reports on. Classes with no claims are left out.
Part D claims for drugs CMS names, 2023 to 2024
- 2023
- 2024
- Claims for drugs CMS names
- 2023: 2,4072024: 2,399No change
Drugs named by CMS: 49 in 2024, 52 in 2023.
Sources: Medicare Part D Prescribers - by Provider and Drug (CMS), 2024 data, released May 6, 2026; and Medicare Part D Prescribers - by Provider (CMS), 2024 data
Dr. Shannon E. O'Mahar offers telehealth to Medicare patients
Dr. O'Mahar accepts Medicare assignment, so Medicare's approved amount is taken as full payment. CMS lists Dr. O'Mahar as offering telehealth.
- Accepts Medicare assignment
- Yes
- Offers telehealth
- Yes
Source: Doctors and Clinicians National Downloadable File (CMS)
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Dr. Shannon E. O'Mahar has 1 publication on record
Dmand AI links 1 paper to Dr. O'Mahar in 2011. Dr. O'Mahar's most frequent co-author is Tien Hoang.
Dr. O'Mahar's most frequent co-authors
Recent publications by Dr. O'Mahar
See who Dr. O'Mahar researches with
Physician Network Discovery turns co-authorship, shared hospitals and shared groups into a map of who Dr. O'Mahar works with, so you can find a warm path to the right hematologists and oncologists.
Sources: PubMed (National Library of Medicine); and Dmand AI Research Linkage
Dr. Shannon E. O'Mahar received $134 in industry payments from 2024 to 2025
CMS Open Payments shows 2 general payments to Dr. O'Mahar from 2 drug and device companies from 2024 to 2025. Food and beverage make up the largest share, 100% of the total. Tempus AI, Inc paid the most, $115.
General payments to Dr. O'Mahar by program year, 2024 to 2025
Companies that paid Dr. O'Mahar the most, 2024 to 2025
Share is of all general payments to this clinician.
Source: Open Payments (CMS), 2025 data, released July 7, 2026
Sources for Dr. Shannon E. O'Mahar's profile data
| Data on this page | Source |
|---|---|
| NPI, name, sex, specialty and licenses | NPPES NPI Registry (CMS) (opens in a new tab)Dmand AI Professional Profile Data |
| Practice locations and phone | Dmand AI Affiliation Data |
| Primary practice, affiliations and health system | Dmand AI Affiliation DataDmand AI Org Hierarchy Data |
| Medicare services and procedure codes | Medicare Physician & Other Practitioners - by Provider and Service (CMS) (opens in a new tab) |
| State medians for the same specialty | Dmand AI Peer Benchmarks |
| Medicare patients and the all-payer patient panel | Dmand AI Patient Panel DataMedicare Physician & Other Practitioners - by Provider (CMS) (opens in a new tab) |
| Part D prescribing | Medicare Part D Prescribers - by Provider and Drug (CMS) (opens in a new tab)Medicare Part D Prescribers - by Provider (CMS) (opens in a new tab) |
| MIPS scores, telehealth, assignment and procedure percentiles | Doctors and Clinicians National Downloadable File (CMS) (opens in a new tab) |
| Publications, topics and co-authors | PubMed (National Library of Medicine) (opens in a new tab)Dmand AI Research Linkage |
| Industry payments | Open Payments (CMS) (opens in a new tab) |
| EHR at each practice site | Dmand AI Technology Install Data |
| Similar physicians | Dmand AI Affiliation Data |
Data last refreshed October 2026Report an inaccuracyRemove my information
FAQ
Frequently asked questions about Dr. Shannon E. O'Mahar
Spotted something out of date? Email hello@dmand.ai and we will check the record. Contact details live in the free trial.
What is Dr. Shannon E. O'Mahar's NPI number?
Dr. Shannon E. O'Mahar's NPI number is 1366569899. It was assigned on March 22, 2007, and it is active in the NPI Registry.
What kind of doctor is Dr. Shannon E. O'Mahar?
Dr. Shannon E. O'Mahar is a hematologist and oncologist in Madison, Wisconsin. The primary specialty in the NPI Registry is Hematology & Oncology Physician (taxonomy code 207RH0003X).
Where does Dr. Shannon E. O'Mahar practice?
Dr. O'Mahar practices at 1211 Fish Hatchery Rd, Madison, WI 53715. Dr. O'Mahar's primary practice is Imaging Services at SSM Health Dean Medical Group (Fish Hatchery Rd) in Madison, Wisconsin. Dmand AI also links Dr. O'Mahar to 4 hospitals and 1 group practice or clinic.
What is Dr. Shannon E. O'Mahar's office phone number?
The practice phone on file for Dr. O'Mahar is (608) 250-1560.
What is Dr. Shannon E. O'Mahar's medical license number?
Dr. O'Mahar holds Wisconsin license 52434-020.
Which hospitals is Dr. Shannon E. O'Mahar affiliated with?
Dr. O'Mahar is affiliated with SSM Health St. Mary's Hospital - Madison. Dmand AI links Dr. O'Mahar to 4 more hospitals.
What medical group is Dr. Shannon E. O'Mahar part of?
Dr. O'Mahar is linked to SSM Health Dean Medical Group.
Does Dr. Shannon E. O'Mahar accept Medicare?
Yes. CMS data shows Dr. O'Mahar billed Medicare for 48,714 services in 2024, and Dr. O'Mahar accepts Medicare assignment.
Does Dr. Shannon E. O'Mahar offer telehealth?
Yes. The CMS Doctors and Clinicians file lists Dr. O'Mahar as offering telehealth services.
How many Medicare patients does Dr. Shannon E. O'Mahar see?
CMS counts 491 Medicare patients who saw Dr. O'Mahar in 2024, with an average age of 74.
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What services does Dr. Shannon E. O'Mahar bill to Medicare?
In 2024, Dr. O'Mahar's most billed Medicare services were injected or infused drug (J9144), injected or infused drug (J9271) and injected or infused drug (J1756).
What drugs does Dr. Shannon E. O'Mahar prescribe most?
In 2024 Medicare Part D data, Dr. O'Mahar's most prescribed drugs by claims were Acyclovir, Revlimid and Dexamethasone.
Has Dr. Shannon E. O'Mahar received payments from drug or device companies?
CMS Open Payments shows $134 in general payments to Dr. O'Mahar from 2 companies from 2024 to 2025. The largest total came from Tempus AI, Inc.
How long has Dr. Shannon E. O'Mahar been practicing?
Dr. O'Mahar graduated from medical school in 2005, 21 years ago.
Does Dr. Shannon E. O'Mahar do research?
Dmand AI links 1 publication to Dr. O'Mahar.
Who does Dr. Shannon E. O'Mahar publish with?
Dr. O'Mahar's most frequent co-authors are Tien Hoang (1 shared paper).
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