Michael Sean Duffy, DO
Internal Medicine Physician · San Diego, CA
Michael Sean Duffy, DO is an internal medicine physician with a practice address in San Diego, California, and NPI 1851399802, issued on Jul 13, 2005. Check the license (California 20A9616, as entered in NPPES) on the Medical Board of California; the Medicare figures below come from public CMS files.
- Name
- Michael Sean Duffy
- Credential
- DO
- Primary taxonomy
- Internal Medicine Physician 207R00000X
- License number
- 20A9616 CA
Self-reported in NPPES; status is on the state search - Practice location
- 1501 5TH Ave Ste 100, San Diego, CA 92101
- Phone
- (619) 647-5072
- Enumerated
- Jul 13, 2005
- Record last updated
- Sep 22, 2022
- Fax
- (619) 330-4782
- Entity
- Type 1 · individual
Also registered at 1501 5TH Ave Ste 100
A shared address usually means a shared clinic or building; it does not show who employs whom.
- John Carey, D.O.Family Medicine Physician1801893672
- Bennadine Johnson, PSYCHOLOGICAL ASSISTPsychologist1679934822
- Heather SpannMarriage & Family Therapist1891267621
Verify Michael Sean Duffy in five checks
- 1IdentityNPI record in CMS NPPESNPI lookupConfirmed in NPPES
- 2LicenseActive license and public ordersMedical Board of California
Search for license 20A9616Check the board - 3Other statesLicenses and actions elsewhereDocInfo (FSMB)Not checked
- 4ExclusionsMedicare and Medicaid bansHHS-OIG exclusion listNot checked
- 5CertificationBoard certificationABMS AOA NCCPA AANPNot checked
99% fewer Medicare Part D claims than the average internal medicine physician in 2024
35 Medicare Part D claims, against an average of 3,176 among the 108,855 providers of this specialty who prescribed in Part D. Brand-name drugs were 0% of claims.
Source: CMS Medicare Part D Prescribers by Provider and Drug, 2024 (data.cms.gov). Part D covers prescriptions for Medicare patients only; drugs with fewer than 11 claims are not published.
Industry payments in 2024: $24.63
1 payment: food and beverage; the largest payer was AstraZeneca Pharmaceuticals LP. The 50,334 providers of this specialty with any payment received $1,303.06 on average. Payments are reported by manufacturers, not by the provider, and are not a sign of wrongdoing.
Source: CMS Open Payments, program year 2024 (openpaymentsdata.cms.gov); average among providers of this specialty with at least one payment.
961 internal medicine physician records list a practice address in San Diego
They are 961 of the 52,937 NPPES records with a practice address in San Diego, and 17,696 internal medicine physician records in California.
All 961 in San Diego → All 17,696 in California → Every provider in San Diego →
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- Luba Abascal, MDSan Francisco, CA1023180874
- Michael Abate, MDSacramento, CA1548248131
- Wali Abawi, D.O.Joshua Tree, CA1104362268
Common questions
What is Michael Sean Duffy, DO's NPI number?
Michael Sean Duffy, DO's National Provider Identifier (NPI) is 1851399802, issued on Jul 13, 2005. An NPI identifies a provider in billing; it is not a license.
Where is Michael Sean Duffy, DO located?
The NPPES record lists a practice address at 1501 5TH Ave Ste 100, San Diego, CA, 92101. Phone: (619) 647-5072. Providers update this record themselves, so call before visiting.
How can I verify Michael Sean Duffy, DO's license?
NPPES lists California license number 20A9616, as entered by the provider. Search the Medical Board of California at https://www.mbc.ca.gov/License-Verification/default.aspx. The NPPES record confirms identity only; the state search shows license status, expiration and public orders.
How much does Michael Sean Duffy, DO prescribe under Medicare Part D?
In 2024, Michael Sean Duffy, DO had 35 Medicare Part D claims; the average among internal medicine physician prescribers was 3,176. Part D covers Medicare prescriptions only.
Source: CMS National Plan and Provider Enumeration System (NPPES), file of Aug 9, 2026 (NPPES files on CMS.gov); NUCC Health Care Provider Taxonomy. Medicare files from data.cms.gov. An NPI identifies who bills; it is not a license.
Figures on PlainDoctor are read from the federal files each page names (CMS NPPES, Medicare Part D, MIPS, Open Payments; the HHS-OIG exclusion list only as counts) and from Census population estimates, with the file date shown beside them. See our editorial standards & corrections policy, the methodology behind these numbers, or report a data error. Data current as of Aug 9, 2026.