Thomas Neil O'Callaghan, MD
Internal Medicine Physician · Ann Arbor, MI
Thomas Neil O'Callaghan, MD is an internal medicine physician with a practice address in Ann Arbor, Michigan, and NPI 1265926331, issued on Jun 21, 2018. Check the license (Michigan 4301507148, as entered in NPPES) on the Michigan Board of Medicine (LARA); the Medicare figures below come from public CMS files.
- Name
- Thomas Neil O'Callaghan
- Credential
- MD
- Primary taxonomy
- Internal Medicine Physician 207R00000X
- License number
- 4301507148 MI
Self-reported in NPPES; status is on the state search - Practice location
- 1500 E Medical Center Dr, Ann Arbor, MI 48109
- Phone
- (734) 936-4000
- Enumerated
- Jun 21, 2018
- Record last updated
- Jul 25, 2022
- Medicare enrollment
- Enrolled (PECOS I20220523001861); accepts Medicare assignment
- Medical or professional school
- University Of Michigan Medical School, 2022
- Entity
- Type 1 · individual
8 nearest internal medicine physician records → All 5,735 in Michigan → Look up another NPI →
Also registered at 1500 E Medical Center Dr
A shared address usually means a shared clinic or building; it does not show who employs whom.
- Bryan Aaron, MDObstetrics & Gynecology Physician1578307724
- Keith Aaronson, MDAdvanced Heart Failure and Transplant Cardiology Physician1144305301
- Rajani Aatre, M.S., M.SC.Genetic Counselor (M.S.)1962122457
- Anjelica Abate, MDDiagnostic Radiology Physician1841819216
- Nicole Abbott, CRNACertified Registered Nurse Anesthetist1790329860
- Ahmed Abdel-Latif, M.D.Interventional Cardiology Physician1518181239
Verify Thomas Neil O'Callaghan in five checks
- 1IdentityNPI record in CMS NPPESNPI lookupConfirmed in NPPES
- 2LicenseActive license and public ordersMichigan Board of Medicine (LARA)
Search for license 4301507148Check the board - 3Other statesLicenses and actions elsewhereDocInfo (FSMB)Not checked
- 4ExclusionsMedicare and Medicaid bansHHS-OIG exclusion listNot checked
- 5CertificationBoard certificationABMS AOA NCCPA AANPNot checked
Bills Medicare through 2 group practices
- Chelsea Community HospitalChelsea, MI
- Regents OF The University OF MichiganAnn Arbor, MI
Source: CMS Doctors and Clinicians National Downloadable File (the group practices a clinician bills Medicare through) (data.cms.gov).
Thomas Neil O'Callaghan among 5,735 internal medicine physician records in Michigan
Thomas Neil O'Callaghan, MD is one of 5,735 internal medicine physician records with a practice address in Michigan. 79% of them appear in a Medicare file (Part D prescribing, MIPS, Open Payments or Medicare group billing); this one does. Its NPI, issued in 2018, is newer than 74% of them.
- NPI issued2018 · 74% of these records are older, 24% newer
- In a Medicare fileYes · 79% of these records are
- In the CMS Doctors and Clinicians fileYes · 62% of these records are
- Graduated2022 · median 2006 among the 3,564 with a school on file
- Record last updated2022 · 54% of these records were not updated in five years or more
Source: CMS NPPES, file of Aug 9, 2026, every record with primary taxonomy 207R00000X and a Michigan practice address; Medicare files: CMS Part D Prescribers 2024, MIPS 2023, Open Payments 2024, Doctors and Clinicians (data.cms.gov).
479 internal medicine physician records list a practice address in Ann Arbor
They are 479 of the 15,616 NPPES records with a practice address in Ann Arbor, and 5,735 internal medicine physician records in Michigan.
All 5,735 in Michigan → Every provider in Ann Arbor → Internal Medicine Physician nationwide →
The 8 internal medicine physician records with the nearest ZIP codes
- Lawrence An, M.D.Ann Arbor, MI 481091003850611
- John Ayanian, MDAnn Arbor, MI 481091164488805
- Daniel Berland, MDAnn Arbor, MI 481091063417731
- Marian Boxer, M.D.Ann Arbor, MI 481091932176906
- Rawden Evans, MDAnn Arbor, MI 481091699718395
- Janice Farrehi, MDAnn Arbor, MI 481091689616310
- Jason Ham, MB, BCH, BAOAnn Arbor, MI 481091275513624
- Min Jiang, MDAnn Arbor, MI 481091194782490
Common questions
What is Thomas Neil O'Callaghan, MD's NPI number?
Thomas Neil O'Callaghan, MD's National Provider Identifier (NPI) is 1265926331, issued on Jun 21, 2018. An NPI identifies a provider in billing; it is not a license.
Where is Thomas Neil O'Callaghan, MD located?
The NPPES record lists a practice address at 1500 E Medical Center Dr, Ann Arbor, MI, 48109. Phone: (734) 936-4000. Providers update this record themselves, so call before visiting.
How can I verify Thomas Neil O'Callaghan, MD's license?
NPPES lists Michigan license number 4301507148, as entered by the provider. Search the Michigan Board of Medicine (LARA) at https://aca-prod.accela.com/MILARA/GeneralProperty/PropertyLookUp.aspx?isLicensee=Y&TabName=APO. The NPPES record confirms identity only; the state search shows license status, expiration and public orders.
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.