Andrew Mark Gregg, MD PHD
Gastroenterology Physician · Thousand Oaks, CA
Andrew Mark Gregg, MD PHD is a gastroenterology physician with a practice address in Thousand Oaks, California, and NPI 1942769104, issued on Mar 18, 2019. Check the license (California A177654, as entered in NPPES) on the Medical Board of California; the Medicare figures below come from public CMS files.
- Name
- Andrew Mark Gregg
- Credential
- MD PHD
- Primary taxonomy
- Gastroenterology Physician 207RG0100X
- License number
- A177654 CA
Self-reported in NPPES; status is on the state search - Practice location
- 248 Hampshire RD Ste 200, Thousand Oaks, CA 91361
- Phone
- (805) 370-0127
- Enumerated
- Mar 18, 2019
- Record last updated
- Aug 4, 2025
- Medicare enrollment
- Enrolled (PECOS I20250618001840); accepts Medicare assignment
- 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 248 Hampshire RD Ste 200
A shared address usually means a shared clinic or building; it does not show who employs whom.
- Sophia Scattaglia, RDRegistered Dietitian1366114647
- Marinelle Sebastian, FNPPrimary Care Nurse Practitioner1568134831
Verify Andrew Mark Gregg in five checks
- 1IdentityNPI record in CMS NPPESNPI lookupConfirmed in NPPES
- 2LicenseActive license and public ordersMedical Board of California
Search for license A177654Check the board - 3Other statesLicenses and actions elsewhereDocInfo (FSMB)Not checked
- 4ExclusionsMedicare and Medicaid bansHHS-OIG exclusion listNot checked
- 5CertificationBoard certificationABMS AOA NCCPA AANPNot checked
91% fewer Medicare Part D claims than the average gastroenterology physician in 2024
75 Medicare Part D claims for 40 beneficiaries, against an average of 811 among the 16,445 providers of this specialty who prescribed in Part D.
Most prescribed
- Pantoprazole Sodium16 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
- The Regents OF The University OF CaliforniaThousand Oaks, CA
Source: CMS Doctors and Clinicians National Downloadable File (the group practices a clinician bills Medicare through) (data.cms.gov).
Andrew Mark Gregg among 2,140 gastroenterology physician records in California
Andrew Mark Gregg, MD PHD 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 2019, is newer than 96% of them.
- NPI issued2019 · 96% of these records are older, 2% newer
- In a Medicare fileYes · 83% of these records are
- In the CMS Doctors and Clinicians fileYes · 72% of these records are
- Graduated2019 · median 2002 among the 1,538 with a school on file
- Record last updated2025 · 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 Thousand Oaks → Gastroenterology Physician nationwide →
The 8 gastroenterology physician records with the nearest ZIP codes
- Hector Caballero, MDWestlake Village, CA 913611174515662
- Cristina Wiese, MDThousand Oaks, CA 913611710921564
- Michael Albertson, M.D.Thousand Oaks, CA 913601114035128
- Shahram Daneshgar, MDThousand Oaks, CA 913601730191875
- Kumar Desai, M.D.Thousand Oaks, CA 913601841495728
- Bonaventure Eng, MDThousand Oaks, CA 913601538366489
- Gregory Johnson, MDThousand Oaks, CA 913601952463762
- Steven Kind, MDThousand Oaks, CA 913601811005044
Common questions
What is Andrew Mark Gregg, MD PHD's NPI number?
Andrew Mark Gregg, MD PHD's National Provider Identifier (NPI) is 1942769104, issued on Mar 18, 2019. An NPI identifies a provider in billing; it is not a license.
Where is Andrew Mark Gregg, MD PHD located?
The NPPES record lists a practice address at 248 Hampshire RD Ste 200, Thousand Oaks, CA, 91361. Phone: (805) 370-0127. Providers update this record themselves, so call before visiting.
How can I verify Andrew Mark Gregg, MD PHD's license?
NPPES lists California license number A177654, 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 Andrew Mark Gregg, MD PHD prescribe under Medicare Part D?
In 2024, Andrew Mark Gregg, MD PHD had 75 Medicare Part D claims for 40 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.