Geoffrey S. Spencer, MD
Gastroenterology Physician · San Jose, CA
Geoffrey S. Spencer, MD is a gastroenterology physician with a practice address in San Jose, California, and NPI 1578625828, issued on Dec 14, 2006. Check the license (California A108150, as entered in NPPES) on the Medical Board of California; the Medicare figures below come from public CMS files.
- Name
- Geoffrey S. Spencer
- Credential
- MD
- Primary taxonomy
- Gastroenterology Physician 207RG0100X
- License numbers
- A108150 CA
MD421763 PA
Self-reported in NPPES; status is on the state search - Practice location
- 2440 Samaritan Dr, San Jose, CA 95124
- Phone
- (408) 626-7375
- Enumerated
- Dec 14, 2006
- Record last updated
- Jul 14, 2009 (not updated in 17 years: call before relying on the address or phone)
- Fax
- (408) 626-7368
- Medicare enrollment
- Enrolled (PECOS I20091110000230); accepts Medicare assignment
- Medical or professional school
- Eastern Virginia Medical School, 2000
- Telehealth
- Offers telehealth (CMS)
- Entity
- Type 1 · individual
8 nearest gastroenterology physician records → All 2,140 in California → Look up another NPI →
Also registered at 2440 Samaritan Dr
A shared address usually means a shared clinic or building; it does not show who employs whom.
- Krikor Barsoumian, M.D.Ophthalmology Physician1649296021
- David Stein, MDGastroenterology Physician1760461719
Verify Geoffrey S. Spencer in five checks
- 1IdentityNPI record in CMS NPPESNPI lookupConfirmed in NPPES
- 2LicenseActive license and public ordersMedical Board of California
Search for license A108150Check the board - 3Other statesLicenses and actions elsewhereDocInfo (FSMB)Not checked
- 4ExclusionsMedicare and Medicaid bansHHS-OIG exclusion listNot checked
- 5CertificationBoard certificationABMS AOA NCCPA AANPNot checked
50% more Medicare Part D claims than the average gastroenterology physician in 2024
1,219 Medicare Part D claims for 605 beneficiaries, against an average of 811 among the 16,445 providers of this specialty who prescribed in Part D. Brand-name drugs were 20% of claims.
Most prescribed
- Sod Sulf-Potass Sulf-Mag Sulf247 claims
- Omeprazole182 claims
- Peg 3350-Electrolyte172 claims
- Pantoprazole Sodium120 claims
- Famotidine63 claims
- Mesalamine40 claims
Source: CMS Medicare Part D Prescribers by Provider and Drug, 2024 (data.cms.gov). Part D covers prescriptions for Medicare patients only; drugs with fewer than 11 claims are not published.
Bills Medicare through one group practice
- Sutter Bay Medical FoundationSan Jose, CA
Source: CMS Doctors and Clinicians National Downloadable File (the group practices a clinician bills Medicare through) (data.cms.gov).
Geoffrey S. Spencer among 2,140 gastroenterology physician records in California
Geoffrey S. Spencer, MD is one of 2,140 gastroenterology physician records with a practice address in California. 83% of them appear in a Medicare file (Part D prescribing, MIPS, Open Payments or Medicare group billing); this one does. Its NPI, issued in 2006, is newer than 7% of them.
- NPI issued2006 · 7% of these records are older, 48% newer
- In a Medicare fileYes · 83% of these records are
- In the CMS Doctors and Clinicians fileYes · 72% of these records are
- Graduated2000 · median 2002 among the 1,538 with a school on file
- Record last updated2009 · 60% of these records were not updated in five years or more
Source: CMS NPPES, file of Aug 9, 2026, every record with primary taxonomy 207RG0100X and a California practice address; Medicare files: CMS Part D Prescribers 2024, MIPS 2023, Open Payments 2024, Doctors and Clinicians (data.cms.gov).
Gastroenterology Physician providers in California
There are 2,140 gastroenterology physician records in California.
All 2,140 in California → Every provider in San Jose → Gastroenterology Physician nationwide →
The 8 gastroenterology physician records with the nearest ZIP codes
- Marwan Balaa, MDSan Jose, CA 951241689652935
- Suejin Kim, MDSan Jose, CA 951241427282714
- Michael Kushlan, M.D.San Jose, CA 951241538273073
- Terry Lin, D.OSan Jose, CA 951241134258213
- Sheila Savur, M.D.San Jose, CA 951241194836585
- David Stein, MDSan Jose, CA 951241760461719
- Alice Yang, M.D.San Jose, CA 951241669662896
- Allison Zhang, MDSan Jose, CA 951241821435900
Common questions
What is Geoffrey S. Spencer, MD's NPI number?
Geoffrey S. Spencer, MD's National Provider Identifier (NPI) is 1578625828, issued on Dec 14, 2006. An NPI identifies a provider in billing; it is not a license.
Where is Geoffrey S. Spencer, MD located?
The NPPES record lists a practice address at 2440 Samaritan Dr, San Jose, CA, 95124. Phone: (408) 626-7375. Providers update this record themselves, so call before visiting.
How can I verify Geoffrey S. Spencer, MD's license?
NPPES lists California license number A108150, as entered by the provider. Search the Medical Board of California at https://www.mbc.ca.gov/License-Verification/default.aspx. The NPPES record confirms identity only; the state search shows license status, expiration and public orders.
How much does Geoffrey S. Spencer, MD prescribe under Medicare Part D?
In 2024, Geoffrey S. Spencer, MD had 1,219 Medicare Part D claims for 605 beneficiaries; the average among gastroenterology physician prescribers was 811. Part D covers Medicare prescriptions only.
Source: CMS National Plan and Provider Enumeration System (NPPES), file of Aug 9, 2026 (NPPES files on CMS.gov); NUCC Health Care Provider Taxonomy. Medicare files from data.cms.gov. An NPI identifies who bills; it is not a license.
Figures on PlainDoctor are read from the federal files each page names (CMS NPPES, Medicare Part D, MIPS, Open Payments; the HHS-OIG exclusion list only as counts) and from Census population estimates, with the file date shown beside them. See our editorial standards & corrections policy, the methodology behind these numbers, or report a data error. Data current as of Aug 9, 2026.