Diana Hess, MD
NPI 1295296275 · Internal Medicine Physician · Castro Valley, CA
Enrolled with Medicare as Practitioner - Internal Medicine · source: CMS PECOS Public Provider Enrollment (2026.04.01)
Diana Hess, MD is a Internal Medicine Physician provider in Castro Valley, CA (NPI 1295296275).
Provider details
- NPI number
- 1295296275
- Entity type
- Individual
- Primary specialty
- Internal Medicine PhysicianAllopathic & Osteopathic Physicians
- Credential
- MD
- Sex
- Female
- Sole proprietor
- No
- License
- 178427 (CA)
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
7 yrs in NPPES registry
- Profile completeness28% of score
100% of core fields populated
- Practice footprint17% of score
3 documented practice locations
- Medicare service volume (vs. specialty peers)28% of score
129 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) |
|---|---|---|
| Established Patient Office Or Other Outpatient Visit With Low Level OD Decision Making, If Using Time, 20 Minutes Or More99213 | 78 | $94 |
| Established Patient Office Or Other Outpatient Visit With Moderate Level of Decision Making, If Using Time, 30 Minutes Or More99214 | 37 | $121 |
| New Patient Office Or Other Outpatient Visit With Moderate Level of Medical Decision Making, If Using Time, 45 Minutes Or More99204 | 14 | $181 |
Typical Medicare-allowed amounts for these services range $94–$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.
What this provider prescribes (Medicare Part D)
Top drugs by Medicare Part D claim volume, 2024 · 18 distinct drugs on file.
| Drug | Part D claims (2024) | Beneficiaries |
|---|---|---|
| Atorvastatin Calcium | 48 | 19 |
| Losartan Potassium | 37 | 13 |
| Rosuvastatin Calcium | 37 | 11 |
| Amlodipine Besylate | 29 | 12 |
| Levothyroxine Sodium | 29 | 13 |
| Metformin Hcl | 26 | — |
| Albuterol Sulfate |
Practice location
Mailing address
Additional practice locations (2)
- 101 the City Dr S Ste 400Orange, CA 92868-3201Phone: (714) 456-5691Fax: (714) 456-8874
- 1451 Irvine BlvdTustin, CA 92780-3804Phone: (714) 838-8878
Registry dates
- Enumerated
- 2019-03-30
- Last updated
- 2024-10-30
- Certified
- 2024-10-30
Frequently asked questions
- What is Diana Hess's NPI number?
- Diana Hess's National Provider Identifier (NPI) is 1295296275, a unique 10-digit ID issued by CMS for use in standard healthcare transactions.
- What is Diana Hess's specialty?
- Diana Hess is listed in the NPPES registry with a primary specialty of Internal Medicine Physician (Allopathic & Osteopathic Physicians).
- Where is Diana Hess located?
- Diana Hess's practice location on file with NPPES is 20101 Lake Chabot Rd Fl 3, Castro Valley, CA 94546-5305.
- What is Diana Hess's phone number?
- The practice phone number listed in the NPPES registry for Diana Hess is (510) 886-3400.
- Does Diana Hess accept Medicare?
- Diana Hess is approved to bill Medicare according to CMS PECOS enrollment data (2026.04.01). Confirm current participation with the provider before scheduling.
- Is Diana Hess's NPI active?
- Yes — Diana Hess's NPI (1295296275) is active in the NPPES registry as of the last update on 2024-10-30.
Source: CMS NPPES Data Dissemination (June 2026). NPI Central is not affiliated with CMS. Data is provided as-is from the public registry.