John Mason, MD
NPI 1023090099 · Emergency Medicine Physician · Tempe, AZ
Enrolled with Medicare as Practitioner - Emergency Medicine · source: CMS PECOS Public Provider Enrollment (2026.04.01)
John Mason, MD is a Emergency Medicine Physician provider in Tempe, AZ (NPI 1023090099).
Provider details
- NPI number
- 1023090099
- Entity type
- Individual
- Primary specialty
- Emergency Medicine PhysicianAllopathic & Osteopathic Physicians
- Credential
- MD
- Sex
- Male
- Sole proprietor
- No
- License
- 31338 (AZ)
Specialties & taxonomies
Allopathic & Osteopathic Physicians
Profile Score
A profile completeness & documented-activity index — NOT a quality, outcomes, or patient-satisfaction rating.
- Registry tenure28% of score
20 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
38 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) |
|---|---|---|
| Emergency Department Visit With High Level of Medical Decision Making99285 | 22 | $167 |
| Emergency Department Visit With Moderate Level of Medical Decision Making99284 | 16 | $116 |
Typical Medicare-allowed amounts for these services range $116–$167 (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
Registry dates
- Enumerated
- 2005-11-16
- Last updated
- 2019-04-18
Frequently asked questions
- What is John Mason's NPI number?
- John Mason's National Provider Identifier (NPI) is 1023090099, a unique 10-digit ID issued by CMS for use in standard healthcare transactions.
- What is John Mason's specialty?
- John Mason is listed in the NPPES registry with a primary specialty of Emergency Medicine Physician (Allopathic & Osteopathic Physicians).
- Where is John Mason located?
- John Mason's practice location on file with NPPES is 1500 S Mill Ave, Tempe, AZ 85281-6699.
- What is John Mason's phone number?
- The practice phone number listed in the NPPES registry for John Mason is (480) 784-5533.
- Does John Mason accept Medicare?
- John Mason is approved to bill Medicare according to CMS PECOS enrollment data (2026.04.01). Confirm current participation with the provider before scheduling.
- Is John Mason's NPI active?
- Yes — John Mason's NPI (1023090099) is active in the NPPES registry as of the last update on 2019-04-18.
Source: CMS NPPES Data Dissemination (June 2026). NPI Central is not affiliated with CMS. Data is provided as-is from the public registry.