Doctor profile · Federal record

Dr. Diana Hess, MD

Internal Medicine Physician (CMS: Internal Medicine) · Castro Valley, CA

  • NPI 1295296275
  • Accepts Medicare
  • 7 yrs in practice
  • Female
  • Group practice
  • No sanctions

Practice & contact

Operates at 3 locations .

NPPES Updated May 11, 2026
Primary practice
20101 Lake Chabot RD Fl 3
Castro Valley, CA 945465305
(510) 886-3400
Additional location
101 the City Dr S Ste 400
Orange, CA 928683201
(714) 456-5691
fax (714) 456-8874
Additional location
1451 Irvine Blvd
Tustin, CA 927803804
(714) 838-8878
Mailing address
Po Box 276950
Sacramento, CA 958276950

Credentials & registration

NPPES · NUCC
NPI registered
March 2019 — 7 yrs on file
Profile last updated
October 30, 2024
Year of graduation
2019 — 7 yrs since
Specialty taxonomy
207R00000X — NUCC code
State license (1)
California #178427

Federal sanctions & exclusions

OIG LEIE Updated May 11, 2026

No sanctions, exclusions or revocations on file

Checked against OIG LEIE on NPI 1295296275. Last verified May 11, 2026.

Medicare procedures · 2023

Top services delivered

CMS Provider Utilization
Total services
409
Distinct HCPCS
9
Medicare allowed
$44,229
HCPCS Description Services Patients Avg allowed
99213 Established patient office or other outpatient visit, 20-29 minutes 156 95 $82
99214 Established patient office or other outpatient visit, 30-39 minutes 113 71 $111
99204 New patient office or other outpatient visit, 45-59 minutes 43 43 $179
G0439 Annual wellness visit, includes a personalized prevention plan of service (pps), subsequent visit 29 29 $90
99205 New patient office or other outpatient visit, 60-74 minutes 17 17 $237
99203 New patient office or other outpatient visit, 30-44 minutes 15 15 $121
G0008 Administration of influenza virus vaccine 13 13 $33
90662 Influenza vaccine split virus, preservative free 12 12 $72
G0438 Annual wellness visit; includes a personalized prevention plan of service (pps), initial visit 11 11 $129

In context: peer comparison

Among 12 peers in Castro Valley Internal Medicine Physician, average services per provider: 154. This provider delivers 2.7× the peer median.

Medicare Part D · 2023

Top prescriptions

CMS Part D Prescriber
Total claims
419
Patients
113
Total drug cost
$5,872
Drug Type Claims Patients Total cost
Amlodipine Besylate Generic 57 19 $585
Atorvastatin Calcium Generic 53 26 $880
Levothyroxine Sodium Generic 40 17 $885
Alprazolam Generic 28 0 $43
Gabapentin Generic 27 0 $147
Metformin Hcl Generic 26 11 $383
Rosuvastatin Calcium Generic 26 12 $881
Losartan Potassium Generic 25 12 $467
Diclofenac Sodium Generic 24 16 $720
Furosemide Generic 20 0 $206

Hospital affiliations

CMS Hospital Compare

Frequently asked questions

Auto-generated from federal data
What is Dr. Diana Hess's medical specialty?
Dr. Diana Hess practices Internal Medicine Physician in Castro Valley, CA.
Where does Dr. Diana Hess practice?
Dr. Diana Hess practices at 20101 Lake Chabot RD Fl 3, Castro Valley, CA 945465305. Office phone: 5108863400.
What is Dr. Diana Hess's NPI?
Dr. Diana Hess's National Provider Identifier (NPI) is 1295296275, issued by NPPES.
Does Dr. Diana Hess accept Medicare assignment?
Yes. Dr. Diana Hess accepts Medicare assignment, meaning Medicare-allowed amounts are accepted as full payment for covered services.
What procedures does Dr. Diana Hess commonly perform?
Top Medicare-reported procedures in 2023: Established patient office or other outpatient visit (HCPCS 99213); Established patient office or other outpatient visit (HCPCS 99214); New patient office or other outpatient visit (HCPCS 99204). Source: CMS Medicare Physician & Other Practitioners file.