Mark Yarwood Johnson, M.D.
Gastroenterology Physician · Chula Vista, CA
Mark Yarwood Johnson, M.D. is a gastroenterology physician with a practice address in Chula Vista, California, and NPI 1861421372, issued on Jun 30, 2006. Check the license (California G28163, as entered in NPPES) on the Medical Board of California; the Medicare figures below come from public CMS files.
- Name
- Mark Yarwood Johnson
- Credential
- M.D.
- Primary taxonomy
- Gastroenterology Physician 207RG0100X
- License number
- G28163 CA
Self-reported in NPPES; status is on the state search - Practice location
- 480 4TH Ave, Chula Vista, CA 91910
- Phone
- (619) 585-0313
- Enumerated
- Jun 30, 2006
- Record last updated
- Oct 4, 2007 (not updated in 19 years: call before relying on the address or phone)
- Fax
- (619) 585-0037
- Medicaid ID
- 00G281630 CA
- Entity
- Type 1 · individual
8 nearest gastroenterology physician records → All 2,140 in California → Look up another NPI →
Also registered at 480 4TH Ave
A shared address usually means a shared clinic or building; it does not show who employs whom.
- Raymundo Alatorre, PHARMDPharmacist1679901516
- Kousay Alkourainy, M.D.Hematology & Oncology Physician1457361271
- Laura Bradley, PA-CMedical Physician Assistant1902359607
- Craig Brown, MDPsychiatry Physician1730239989
- Jennifer Crittenden, D.P.TPhysical Therapist1700138732
- John Duque, M.D.Gastroenterology Physician1295710747
Verify Mark Yarwood Johnson in five checks
- 1IdentityNPI record in CMS NPPESNPI lookupConfirmed in NPPES
- 2LicenseActive license and public ordersMedical Board of California
Search for license G28163Check the board - 3Other statesLicenses and actions elsewhereDocInfo (FSMB)Not checked
- 4ExclusionsMedicare and Medicaid bansHHS-OIG exclusion listNot checked
- 5CertificationBoard certificationABMS AOA NCCPA AANPNot checked
76% fewer Medicare Part D claims than the average gastroenterology physician in 2024
193 Medicare Part D claims for 80 beneficiaries, against an average of 811 among the 16,445 providers of this specialty who prescribed in Part D. Brand-name drugs were 9% of claims.
Most prescribed
- Omeprazole59 claims
- Dicyclomine Hcl26 claims
- Fluoxetine Hcl14 claims
- Pantoprazole Sodium14 claims
- Peg 3350-Electrolyte12 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.
Mark Yarwood Johnson among 2,140 gastroenterology physician records in California
Mark Yarwood Johnson, M.D. 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 fileNo · 72% of these records are
- Record last updated2007 · 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 Chula Vista → Gastroenterology Physician nationwide →
The 8 gastroenterology physician records with the nearest ZIP codes
- Erick Alayo, M.D.Chula Vista, CA 919101841454758
- Ivan Cubas, MDChula Vista, CA 919101447464912
- John Duque, M.D.Chula Vista, CA 919101295710747
- Gregory Wiener, M.DChula Vista, CA 919101811099534
- Steven Brozinsky, M.D.Chula Vista, CA 919111649266834
- Errol Korn, M.D.Chula Vista, CA 919111922041052
- Edward Singer, M.D.Chula Vista, CA 919111679569743
- Mohammad Soleimanpour, M.D.La Mesa, CA 919411194714527
Common questions
What is Mark Yarwood Johnson, M.D.'s NPI number?
Mark Yarwood Johnson, M.D.'s National Provider Identifier (NPI) is 1861421372, issued on Jun 30, 2006. An NPI identifies a provider in billing; it is not a license.
Where is Mark Yarwood Johnson, M.D. located?
The NPPES record lists a practice address at 480 4TH Ave, Chula Vista, CA, 91910. Phone: (619) 585-0313. Providers update this record themselves, so call before visiting.
How can I verify Mark Yarwood Johnson, M.D.'s license?
NPPES lists California license number G28163, 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 Mark Yarwood Johnson, M.D. prescribe under Medicare Part D?
In 2024, Mark Yarwood Johnson, M.D. had 193 Medicare Part D claims for 80 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.