John Mersch, M.D.
Pediatrics Physician · Ladera Ranch, CA
John Mersch, M.D. is a pediatrics physician with a practice address in Ladera Ranch, California, and NPI 1588769558, issued on Sep 14, 2006. Check the license (California G40887, as entered in NPPES) on the Medical Board of California; the federal record below is the public data PlainDoctor holds for this provider.
- Name
- John Mersch
- Credential
- M.D.
- Primary taxonomy
- Pediatrics Physician 208000000X
- License number
- G40887 CA
Self-reported in NPPES; status is on the state search - Practice location
- 777 Corporate Dr, Ladera Ranch, CA 92694
- Phone
- (949) 388-1798
- Enumerated
- Sep 14, 2006
- Record last updated
- Mar 13, 2012 (not updated in 14 years: call before relying on the address or phone)
- Entity
- Type 1 · individual
8 nearest pediatrics physician records → All 9,272 in California → Look up another NPI →
Also registered at 777 Corporate Dr
A shared address usually means a shared clinic or building; it does not show who employs whom.
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- Lincoln Parker, D.M.DDentist1831536846
- Sharon Randlett Major, RN, BS, IBCLCLactation Consultant (Registered Nurse)1437420676
Verify John Mersch in five checks
- 1IdentityNPI record in CMS NPPESNPI lookupConfirmed in NPPES
- 2LicenseActive license and public ordersMedical Board of California
Search for license G40887Check the board - 3Other statesLicenses and actions elsewhereDocInfo (FSMB)Not checked
- 4ExclusionsMedicare and Medicaid bansHHS-OIG exclusion listNot checked
- 5CertificationBoard certificationABMS AOA NCCPA AANPNot checked
John Mersch among 9,272 pediatrics physician records in California
John Mersch, M.D. is one of 9,272 pediatrics physician records with a practice address in California. 31% of them appear in a Medicare file (Part D prescribing, MIPS, Open Payments or Medicare group billing); this one does not. Its NPI, issued in 2006, is newer than 4% of them.
- NPI issued2006 · 4% of these records are older, 56% newer
- In a Medicare fileNo · 31% of these records are
- In the CMS Doctors and Clinicians fileNo · 8% of these records are
- Record last updated2012 · 65% of these records were not updated in five years or more
Source: CMS NPPES, file of Aug 9, 2026, every record with primary taxonomy 208000000X and a California practice address; Medicare files: CMS Part D Prescribers 2024, MIPS 2023, Open Payments 2024, Doctors and Clinicians (data.cms.gov).
8 pediatrics physician records list a practice address in Ladera Ranch
They are 8 of the 264 NPPES records with a practice address in Ladera Ranch, and 9,272 pediatrics physician records in California. No Medicare prescribing, quality score, industry payment or hospital affiliation is published for this NPI.
All 9,272 in California → Every provider in Ladera Ranch → Pediatrics Physician nationwide →
The 8 pediatrics physician records with the nearest ZIP codes
- Christine Comulada, MDLadera Ranch, CA 926941356481642
- Amy Cox, M.D.Ladera Ranch, CA 926941568567527
- Kenson Lo, M.D.Ladera Ranch, CA 926941245301407
- Meena Tanwar-Ahuja, M.D.Ladera Ranch, CA 926941649584426
- Lisa Teschke-Nguyen, M.D.Ladera Ranch, CA 926941538265285
- Trung Truong, MDRancho Mission Viejo, CA 926941801877170
- Clyde Wesp, M.D.Ladera Ranch, CA 926941679679336
- Leann Williams, MDLadera Ranch, CA 926941437451499
Common questions
What is John Mersch, M.D.'s NPI number?
John Mersch, M.D.'s National Provider Identifier (NPI) is 1588769558, issued on Sep 14, 2006. An NPI identifies a provider in billing; it is not a license.
Where is John Mersch, M.D. located?
The NPPES record lists a practice address at 777 Corporate Dr, Ladera Ranch, CA, 92694. Phone: (949) 388-1798. Providers update this record themselves, so call before visiting.
How can I verify John Mersch, M.D.'s license?
NPPES lists California license number G40887, 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.
Source: CMS National Plan and Provider Enumeration System (NPPES), file of Aug 9, 2026 (NPPES files on CMS.gov); NUCC Health Care Provider Taxonomy. 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.