Christopher F. Calahan, MD
Internal Medicine Physician · Boston, MA
Christopher F. Calahan, MD is an internal medicine physician with a practice address in Boston, Massachusetts, and NPI 1558821983, issued on Mar 21, 2019. Check the license (Massachusetts 1018450, as entered in NPPES) on the Massachusetts Board of Registration in Medicine; the Medicare figures below come from public CMS files.
- Name
- Christopher F. Calahan
- Credential
- MD
- Primary taxonomy
- Internal Medicine Physician 207R00000X
- License number
- 1018450 MA
Self-reported in NPPES; status is on the state search - Practice location
- 55 Fruit St, Boston, MA 02114
- Phone
- (617) 643-8245
- Enumerated
- Mar 21, 2019
- Record last updated
- Dec 29, 2025
- Medicare enrollment
- Enrolled (PECOS I20240606001154); accepts Medicare assignment
- Medical or professional school
- Harvard Medical School, 2019
- Entity
- Type 1 · individual
8 nearest internal medicine physician records → All 6,825 in Massachusetts → Look up another NPI →
Also registered at 55 Fruit St
A shared address usually means a shared clinic or building; it does not show who employs whom.
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Verify Christopher F. Calahan in five checks
- 1IdentityNPI record in CMS NPPESNPI lookupConfirmed in NPPES
- 2LicenseActive license and public ordersMassachusetts Board of Registration in Medicine
Search for license 1018450Check 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
17 Medicare Part D claims, against an average of 3,176 among the 108,855 providers of this specialty who prescribed in Part D.
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.
Bills Medicare through 2 group practices
- Children's Hospital Pediatric Associates, IncBoston, MA
- Massachusetts General Physicians Organization IncBoston, MA
Source: CMS Doctors and Clinicians National Downloadable File (the group practices a clinician bills Medicare through) (data.cms.gov).
Christopher F. Calahan among 6,825 internal medicine physician records in Massachusetts
Christopher F. Calahan, MD is one of 6,825 internal medicine physician records with a practice address in Massachusetts. 75% of them appear in a Medicare file (Part D prescribing, MIPS, Open Payments or Medicare group billing); this one does. Its NPI, issued in 2019, is newer than 84% of them.
- NPI issued2019 · 84% of these records are older, 13% newer
- In a Medicare fileYes · 75% of these records are
- In the CMS Doctors and Clinicians fileYes · 60% of these records are
- Graduated2019 · median 2004 among the 4,103 with a school on file
- Record last updated2025 · 64% 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 Massachusetts practice address; Medicare files: CMS Part D Prescribers 2024, MIPS 2023, Open Payments 2024, Doctors and Clinicians (data.cms.gov).
2,320 internal medicine physician records list a practice address in Boston
They are 2,320 of the 41,865 NPPES records with a practice address in Boston, and 6,825 internal medicine physician records in Massachusetts.
All 6,825 in Massachusetts → Every provider in Boston → Internal Medicine Physician nationwide →
The 8 internal medicine physician records with the nearest ZIP codes
- Jaime Chang, MDBoston, MA 021141205825197
- Jeffrey Engelman, MD PHDBoston, MA 021141538159108
- James Evans, MDBoston, MA 021141215939533
- Nicolette Fontaine, MDBoston, MA 021141841287174
- Nancy Gagliano, MDBoston, MA 021141881680767
- Patricia Gibbons, MDBoston, MA 021141619967221
- Steven Hersch, MDBoston, MA 021141174512149
- Mira Kautzky, M.D.Boston, MA 021141972505402
Common questions
What is Christopher F. Calahan, MD's NPI number?
Christopher F. Calahan, MD's National Provider Identifier (NPI) is 1558821983, issued on Mar 21, 2019. An NPI identifies a provider in billing; it is not a license.
Where is Christopher F. Calahan, MD located?
The NPPES record lists a practice address at 55 Fruit St, Boston, MA, 02114. Phone: (617) 643-8245. Providers update this record themselves, so call before visiting.
How can I verify Christopher F. Calahan, MD's license?
NPPES lists Massachusetts license number 1018450, as entered by the provider. Search the Massachusetts Board of Registration in Medicine at https://findmydoctor.mass.gov/. The NPPES record confirms identity only; the state search shows license status, expiration and public orders.
How much does Christopher F. Calahan, MD prescribe under Medicare Part D?
In 2024, Christopher F. Calahan, MD had 17 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.