Christopher Calahan, MD
NPI 1558821983 · Internal Medicine Physician · Boston, MA
Enrolled with Medicare as Practitioner - Internal Medicine · source: CMS PECOS Public Provider Enrollment (2026.04.01)
Christopher Calahan, MD is a Internal Medicine Physician provider in Boston, MA (NPI 1558821983).
Provider details
- NPI number
- 1558821983
- Entity type
- Individual
- Primary specialty
- Internal Medicine PhysicianAllopathic & Osteopathic Physicians
- Credential
- MD
- Sex
- Male
- Sole proprietor
- No
- License
- 1018450 (MA)
Specialties & taxonomies
Allopathic & Osteopathic Physicians
Allopathic & Osteopathic Physicians
Profile Score
A profile completeness & documented-activity index — NOT a quality, outcomes, or patient-satisfaction rating.
- Registry tenure28% of score
7 yrs in NPPES registry
- Profile completeness28% of score
100% of core fields populated
- Practice footprint17% of score
4 documented practice locations
- Medicare service volume (vs. specialty peers)28% of score
12 Medicare services, 2024 (ranked within specialty)
Medicare volume is ranked against active providers in the same specialty. Signals a provider has no public data for (e.g. Medicare claims) are left out of the score entirely — never counted as zero — so providers without that data are not penalized. See the full formula and weights in our methodology.
What this provider does (Medicare)
Based on Medicare fee-for-service claims, 2024; not all care is captured.
| Service (HCPCS) | Medicare services | Typical Medicare-allowed (2024) |
|---|---|---|
| Initial Hospital Care With Moderate Level of Medical Decision Making, If Using Time, at Least 75 Minutes99223 | 12 | $181 |
Typical Medicare-allowed amounts for these services range $181–$181 (2024). The Medicare-allowed amount is what Medicare recognizes for a service under fee-for-service — a reference figure for 2024, not a price quote and not what you would be billed. Medicare Part B covers roughly an eighth of all NPIs (65+ skew); services with fewer than 11 beneficiaries are suppressed by CMS. Source: CMS Medicare Physician & Other Practitioners, by Provider & Service.
Practice location
Mailing address
Additional practice locations (3)
- 300 Longwood AveBoston, MA 02115-5724Phone: (176) 355-6000
- 75 Francis StBoston, MA 02115-6110Phone: (617) 732-5500
- 1153 Centre StJamaica Plain, MA 02130-3446Phone: (617) 983-7000
Registry dates
- Enumerated
- 2019-03-21
- Last updated
- 2025-12-29
- Certified
- 2025-12-29
Frequently asked questions
- What is Christopher Calahan's NPI number?
- Christopher Calahan's National Provider Identifier (NPI) is 1558821983, a unique 10-digit ID issued by CMS for use in standard healthcare transactions.
- What is Christopher Calahan's specialty?
- Christopher Calahan is listed in the NPPES registry with a primary specialty of Internal Medicine Physician (Allopathic & Osteopathic Physicians).
- Where is Christopher Calahan located?
- Christopher Calahan's practice location on file with NPPES is 55 Fruit St, Boston, MA 02114-2696.
- What is Christopher Calahan's phone number?
- The practice phone number listed in the NPPES registry for Christopher Calahan is (617) 643-8245.
- Does Christopher Calahan accept Medicare?
- Christopher Calahan is approved to bill Medicare according to CMS PECOS enrollment data (2026.04.01). Confirm current participation with the provider before scheduling.
- Is Christopher Calahan's NPI active?
- Yes — Christopher Calahan's NPI (1558821983) is active in the NPPES registry as of the last update on 2025-12-29.
Source: CMS NPPES Data Dissemination (June 2026). NPI Central is not affiliated with CMS. Data is provided as-is from the public registry.