Doctor profile · Federal record
Dr. Gregory Shimizu, MD
Internal Medicine Physician (CMS: Internal Medicine) · Fontana, CA
- NPI 1154492130
- Accepts Medicare
- 38 yrs in practice
- Male
- Group practice
- No sanctions
Practice & contact
- Primary practice
-
9961 Sierra Ave
Fontana, CA 923356720
(909) 427-3910
Credentials & registration
- NPI registered
- November 2006 — 20 yrs on file
- Profile last updated
- September 23, 2008
- Year of graduation
- 1988 — 38 yrs since
- Specialty taxonomy
- 207R00000X — NUCC code
- State license (1)
- California #G67137
Federal sanctions & exclusions
No sanctions, exclusions or revocations on file
Checked against OIG LEIE on NPI 1154492130. Last verified May 11, 2026.Medicare procedures · 2023
Top services delivered
Total services
825
Distinct HCPCS
7
Medicare allowed
$77,753
| HCPCS | Description | Services | Patients | Avg allowed | |
|---|---|---|---|---|---|
99232 |
Subsequent hospital care with moderate levelof medical decision making, if using time, at least 35 minutes | 380 | 139 | $82 | |
99233 |
Subsequent hospital care with moderate levelof medical decision making, if using time, at least 50 minutes | 173 | 68 | $123 | |
99238 |
Hospital discharge day management, 30 minutes or less | 116 | 113 | $84 | |
99497 |
Advance care planning, first 30 minutes | 62 | 54 | $78 | |
99231 |
Subsequent hospital care with straightforward or low level of medical decision making, per day, if using time, at least 25 minutes | 38 | 15 | $51 | |
99223 |
Initial hospital care with moderate level of medical decision making, if using time, at least 75 minutes | 32 | 30 | $179 | |
99222 |
Initial hospital care with straightforward or low-level medical decision making, if using time, at least 55 minutes | 24 | 24 | $134 |
In context: peer comparison
Among 18 peers in Fontana Internal Medicine Physician, average services per provider: 61. This provider delivers 14× the peer median.Hospital affiliations
Frequently asked questions
What is Dr. Gregory Shimizu's medical specialty?
Dr. Gregory Shimizu practices Internal Medicine Physician in Fontana, CA.
Where does Dr. Gregory Shimizu practice?
Dr. Gregory Shimizu practices at 9961 Sierra Ave, Fontana, CA 923356720. Office phone: 9094273910.
What is Dr. Gregory Shimizu's NPI?
Dr. Gregory Shimizu's National Provider Identifier (NPI) is 1154492130, issued by NPPES.
Does Dr. Gregory Shimizu accept Medicare assignment?
Yes. Dr. Gregory Shimizu accepts Medicare assignment, meaning Medicare-allowed amounts are accepted as full payment for covered services.
What procedures does Dr. Gregory Shimizu commonly perform?
Top Medicare-reported procedures in 2023: Subsequent hospital care with moderate levelof medical decision making (HCPCS 99232); Subsequent hospital care with moderate levelof medical decision making (HCPCS 99233); Hospital discharge day management (HCPCS 99238). Source: CMS Medicare Physician & Other Practitioners file.