Mark Allen Schaeffer, M.D.
Internal Medicine Physician · Princeton, NJ
Mark Allen Schaeffer, M.D. is an internal medicine physician with a practice address in Princeton, New Jersey, and NPI 1194866087, issued on Feb 12, 2007. Check the license (New Jersey 25MA04680500, as entered in NPPES) on the New Jersey State Board of Medical Examiners; the Medicare figures below come from public CMS files.
- Name
- Mark Allen Schaeffer
- Credential
- M.D.
- Primary taxonomy
- Internal Medicine Physician 207R00000X
- License number
- 25MA04680500 NJ
Self-reported in NPPES; status is on the state search - Practice location
- 800 Bunn Dr, Princeton, NJ 08540
- Phone
- (609) 921-1680
- Enumerated
- Feb 12, 2007
- Record last updated
- Mar 11, 2012 (not updated in 14 years: call before relying on the address or phone)
- Fax
- (609) 921-1438
- Entity
- Type 1 · individual
8 nearest internal medicine physician records → All 4,632 in New Jersey → Look up another NPI →
Also registered at 800 Bunn Dr
A shared address usually means a shared clinic or building; it does not show who employs whom.
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Verify Mark Allen Schaeffer in five checks
- 1IdentityNPI record in CMS NPPESNPI lookupConfirmed in NPPES
- 2LicenseActive license and public ordersNew Jersey State Board of Medical Examiners
Search for license 25MA04680500Check 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
38 Medicare Part D claims, against an average of 3,176 among the 108,855 providers of this specialty who prescribed in Part D.
Most prescribed
- Ursodiol12 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.
Mark Allen Schaeffer among 4,632 internal medicine physician records in New Jersey
Mark Allen Schaeffer, M.D. is one of 4,632 internal medicine physician records with a practice address in New Jersey. 82% of them appear in a Medicare file (Part D prescribing, MIPS, Open Payments or Medicare group billing); this one does. Its NPI, issued in 2007, is newer than 50% of them.
- NPI issued2007 · 50% of these records are older, 41% newer
- In a Medicare fileYes · 82% of these records are
- In the CMS Doctors and Clinicians fileNo · 68% of these records are
- Record last updated2012 · 63% 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 New Jersey practice address; Medicare files: CMS Part D Prescribers 2024, MIPS 2023, Open Payments 2024, Doctors and Clinicians (data.cms.gov).
66 internal medicine physician records list a practice address in Princeton
They are 66 of the 1,622 NPPES records with a practice address in Princeton, and 4,632 internal medicine physician records in New Jersey.
All 4,632 in New Jersey → Every provider in Princeton → Internal Medicine Physician nationwide →
The 8 internal medicine physician records with the nearest ZIP codes
- David Barile, MDPrinceton, NJ 085401063461283
- Erinn Beagin, M.D.Princeton, NJ 085401619924388
- Frances Chang, MDPrinceton, NJ 085401316996960
- Savneet Chattha, MDPrinceton, NJ 085401629055181
- Douglas Corazza, MDPrinceton, NJ 085401376520825
- Nataliya Dashevsky, MDPrinceton, NJ 085401902857139
- Ernest De La Cruz, MDPrinceton, NJ 085401821075334
- Chandani Fernando, MDPrinceton, NJ 085401679513501
Common questions
What is Mark Allen Schaeffer, M.D.'s NPI number?
Mark Allen Schaeffer, M.D.'s National Provider Identifier (NPI) is 1194866087, issued on Feb 12, 2007. An NPI identifies a provider in billing; it is not a license.
Where is Mark Allen Schaeffer, M.D. located?
The NPPES record lists a practice address at 800 Bunn Dr, Princeton, NJ, 08540. Phone: (609) 921-1680. Providers update this record themselves, so call before visiting.
How can I verify Mark Allen Schaeffer, M.D.'s license?
NPPES lists New Jersey license number 25MA04680500, as entered by the provider. Search the New Jersey State Board of Medical Examiners at https://newjersey.mylicense.com/verification/. The NPPES record confirms identity only; the state search shows license status, expiration and public orders.
How much does Mark Allen Schaeffer, M.D. prescribe under Medicare Part D?
In 2024, Mark Allen Schaeffer, M.D. had 38 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.