Physician Profile
Gregory H. Shimizu, MD
Unclaimed ProfileAbout Dr. Shimizu
Gregory H. Shimizu, MD is a healthcare provider in Fontana, CA specializing in internal medicine. Gregory trained at George Washington University School of Medicine, graduating in 1988. According to Medicare claims data, Gregory cared for 561 Medicare patients across 910 services. The services billed most often include subsequent hospital care with moderate levelof medical decision making, if using time, at least 50 minutes, subsequent hospital care with moderate levelof medical decision making, if using time, at least 35 minutes, and advance care planning, first 30 minutes.
Summarised automatically from public NPI registry and CMS Medicare data. Not written or reviewed by this provider. Claim this profile to replace it — free, and no identity document with a practice or institutional email.
Education & Training
Specialty
Credentials & Licensing
License numbers are what the provider reported to NPPES when the NPI was issued or updated. NPPES does not verify licensure; confirm current standing with the state licensing board.
Medicare information
Exactly as CMS reports it (National Downloadable File, Opt-Out Affidavits, Order & Referring). Not an insurance directory; confirm coverage with the office.
Contact Information
- (909) 427-3910
- Email not available
Practice Locations
9961 SIERRA AVE
Fontana, CA 92335
Conditions Commonly Evaluated or Treated
Within Internal Medicine generally. Availability varies by clinician, training and location — this profile has not been claimed, so nothing here is a personal claim by the provider.
Conditions
Most searched conditions
- Allergies
- Diabetes
- Flu
- Hypothyroidism
- Strep throat
- UTI
Cardiometabolic
- High blood pressure
- High cholesterol
Digestive and liver
- Acid reflux
- Fatty liver disease
- IBS
Endocrine, blood, and bone
- Gout
Infectious disease
- Shingles
Kidney and urinary
- Chronic kidney disease
- Enlarged prostate
Respiratory
- Acute bronchitis
- Asthma
- COPD
Blood & Circulation
- Blood clots
Blood disorders
- Anemia
Brain & Nerves
- Alzheimer's disease
Brain and nerves
- Vertigo
Cardiac and vascular
- AFib
Digestive
- Diverticulitis
Heart & Circulation
- Heart disease
Infections
- Impetigo
Kidney & Bladder
- Overactive Bladder and Leakage
Lungs & Breathing
- Sleep apnea
Mental Health
- Generalized anxiety disorder
- Insomnia and Sleep Problems
Neurologic and behavioral
- Depression
- Migraines
Pain
- Back pain
Rheumatologic and pain
- Osteoarthritis
Procedures & services
Most searched procedures
- Annual physical
- Blood test
- Flu shot
- Medicare wellness visit
- Sick visit
- TB test
- Well-woman exam
Preventive and evaluation
- Medication management
- Post-hospital transitional care
Screening and diagnostic testing
- EKG
- Spirometry
Bones & Joints
- Trigger Point Injections
Brain and nerves
- Epley Maneuver
Cancer screening
- Colon Cancer Screening Referral
- Mammogram Referral
Digestive
- Endoscopy
Exams & Consultations
- Pre-Op Clearance Exam
Heart & Circulation
- Blood Pressure Check
- Heart monitor
Heart health
- Cardiac Stress Test Referral
Imaging referral
- Abdominal Ultrasound Referral
Immunizations
- Tetanus shot
Lab tests
- Urinalysis
Lungs & Breathing
- At-Home Sleep Study Order
Metabolic & Weight
- Weight Loss Injections and Medication
Minor procedures
- Ingrown toenail removal
- Suture removal
Office procedures
- Cryotherapy for skin lesions
- Earwax removal
- Incision and drainage of an abscess
- Skin biopsy
Office Procedures
- Skin Tag and Mole Removal
- Vitamin B12 Injections
- Wart Removal
Pain management
- Knee Joint Injection
Preventive & Routine Care
- Smoking cessation counseling
Screenings & Diagnostics
- Bone Density Scan Referral
- Diabetes Screening and A1C Test
Sexual health
- STI Testing
Procedures Most Often Billed to Medicare
910 services · 561 patients · 6 distinct codes
| Procedure | Type | Code | Services | Compared with peers |
|---|---|---|---|---|
| Subsequent hospital care with moderate levelof medical decision making, if using time, at least 50 minutes | Office visit | 99233 |
357 | More often than most peers in Internal Medicine |
| Subsequent hospital care with moderate levelof medical decision making, if using time, at least 35 minutes | Office visit | 99232 |
232 | More often than most peers in Internal Medicine |
| Advance care planning, first 30 minutes | Office visit | 99497 |
154 | More often than most peers in Internal Medicine |
| Hospital discharge day management, more than 30 minutes | Office visit | 99239 |
94 | As often as other peers in Internal Medicine |
| Initial hospital care with moderate level of medical decision making, if using time, at least 75 minutes | Office visit | 99223 |
58 | As often as other peers in Internal Medicine |
| Smoking and tobacco use intensive counseling, more than 10 minutes | Office visit | 99407 |
15 | Less often than most peers in Internal Medicine |
Source: CMS Medicare public data. Shows how often procedures were billed — not quality of care or patient satisfaction.
Related providers
Connections drawn from the registry and from what providers have told us. A link here is not a referral or an endorsement.
Other internists at this location 2
Same specialty, same street address — most likely the same department or group.
Related specialists at this location 8
Clinically related specialties at the same address — the people this provider most likely works alongside.
Also at this address 4
Providers at the same street address. Each files their own registry entry, so a shared practice often appears under several different names.
More connections — 22 related providers in 3 groups
Other internists in Fontana 6
Same specialty, same city.
Trained at George Washington University School of Medicine 8
Other providers in the same specialty who trained at the same institution.
Class of 1988 at George Washington University School of Medicine 8
Providers who graduated from the same medical school in the same year.
Common questions
What is Dr. Shimizu's specialty?
Dr. Shimizu is an internist in Fontana, CA. That is the designation recorded for this NPI in the federal registry, where it is listed as “Internal Medicine”.
NPI registry
Where can I find Dr. Shimizu?
Dr. Shimizu is listed at 9961 Sierra Ave, Fontana, CA 92335. Addresses come from the NPI registry and can lag a move, so confirm before travelling.
NPI registry
How do I contact Dr. Shimizu?
The number on file is (909) 427-3910. Guide.md cannot book appointments or pass on messages — please call the office directly.
NPI registry
What is Dr. Shimizu's NPI number?
Dr. Shimizu's National Provider Identifier is 1154492130. It is issued by the Centers for Medicare & Medicaid Services and is unique and permanent — it does not change if they move practice.
NPI registry
What is Dr. Shimizu's medical education?
Dr. Shimizu attended George Washington University School of Medicine, graduating in 1988. This comes from the CMS National Downloadable File.
CMS public data
How long has Dr. Shimizu been practicing?
Dr. Shimizu has 38 years experience. Calculated from a graduation year of 1988, reported in the CMS National Downloadable File.
CMS public data
What is Dr. Shimizu known for?
According to Medicare billing data, Dr. Shimizu the Medicare record under this individual NPI shows mainly office visits and diagnostic testing. Hospital-based physicians usually have their procedural work billed by the facility rather than under their own number, so this is a floor on their practice, not a description of it. This reflects Medicare patients only and is billing volume, not a measure of quality.
Medicare claims
Has Dr. Shimizu confirmed this information?
Not yet. This profile is built from public federal data and has not been confirmed by Dr. Shimizu. If this is you, claiming it is free.
Guide.md
Provider data sourced from the NPPES NPI Registry and CMS public datasets. Information is provided for reference and is not medical advice.