Matthew Callahan, M.D.
NPI 1083901839 · Hospitalist Physician · San Diego, CA
Enrolled with Medicare as Practitioner - Hospitalist · source: CMS PECOS Public Provider Enrollment (2026.04.01)
Matthew Callahan, M.D. is a Hospitalist Physician provider in San Diego, CA (NPI 1083901839).
Provider details
- NPI number
- 1083901839
- Entity type
- Individual
- Primary specialty
- Hospitalist PhysicianAllopathic & Osteopathic Physicians
- Credential
- M.D.
- Sex
- Male
- Sole proprietor
- No
- License
- 131315 (CA)
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
14 yrs in NPPES registry
- Profile completeness28% of score
100% of core fields populated
- Practice footprint17% of score
1 documented practice location
- Medicare service volume (vs. specialty peers)28% of score
424 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) |
|---|---|---|
| Subsequent Hospital Care With Moderate Levelof Medical Decision Making, If Using Time, at Least 35 Minutes99232 | 227 | $80 |
| Subsequent Hospital Care With Straightforward Or Low Level of Medical Decision Making, Per Day, If Using Time, at Least 25 Minutes99231 | 112 | $50 |
| Hospital Discharge Day Management, More Than 30 Minutes99239 | 73 | $118 |
| Hospital Discharge Day Management, 30 Minutes Or Less99238 | 12 | $84 |
Typical Medicare-allowed amounts for these services range $50–$118 (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.
What this provider prescribes (Medicare Part D)
Top drugs by Medicare Part D claim volume, 2024 · 8 distinct drugs on file.
| Drug | Part D claims (2024) | Beneficiaries |
|---|---|---|
| Hydrocodone/Acetaminophenbrand: Hydrocodone-Acetaminophen | 19 | 19 |
| Amoxicillin/Potassium Clavbrand: Amoxicillin-Clavulanate Potass | 16 | 16 |
| Amlodipine Besylate | 15 | 15 |
| Oxycodone Hcl | 15 | 15 |
| Metoprolol Tartrate | 14 | 13 |
| Atorvastatin Calcium | 13 | 13 |
Practice location
Mailing address
Registry dates
- Enumerated
- 2011-06-30
- Last updated
- 2019-11-20
Frequently asked questions
- What is Matthew Callahan's NPI number?
- Matthew Callahan's National Provider Identifier (NPI) is 1083901839, a unique 10-digit ID issued by CMS for use in standard healthcare transactions.
- What is Matthew Callahan's specialty?
- Matthew Callahan is listed in the NPPES registry with a primary specialty of Hospitalist Physician (Allopathic & Osteopathic Physicians).
- Where is Matthew Callahan located?
- Matthew Callahan's practice location on file with NPPES is 4077 Fifth Ave, San Diego, CA 92103-2105.
- What is Matthew Callahan's phone number?
- The practice phone number listed in the NPPES registry for Matthew Callahan is (619) 260-7125.
- Does Matthew Callahan accept Medicare?
- Matthew Callahan is approved to bill Medicare according to CMS PECOS enrollment data (2026.04.01). Confirm current participation with the provider before scheduling.
- Is Matthew Callahan's NPI active?
- Yes — Matthew Callahan's NPI (1083901839) is active in the NPPES registry as of the last update on 2019-11-20.
Source: CMS NPPES Data Dissemination (June 2026). NPI Central is not affiliated with CMS. Data is provided as-is from the public registry.