William Robert Mathias, PA-C
Physician Assistant · San Marcos, CA
William Robert Mathias, PA-C is a physician assistant with a practice address in San Marcos, California, and NPI 1285806323, issued on Mar 28, 2008. Check the license (California 59627, as entered in NPPES) with the California board that licenses this profession; the Medicare figures below come from public CMS files.
- Name
- William Robert Mathias
- Credential
- PA-C
- Primary taxonomy
- Physician Assistant 363A00000X
- License numbers
- 59627 CA
085.004666 IL
Self-reported in NPPES; status is on the state search - Practice location
- 150 Valpreda RD, San Marcos, CA 92069
- Phone
- (760) 736-6767
- Enumerated
- Mar 28, 2008
- Record last updated
- Mar 28, 2023
- Medicare enrollment
- Enrolled (PECOS I20230629002934); accepts Medicare assignment
- Entity
- Type 1 · individual
8 nearest physician assistant records → All 14,451 in California → Look up another NPI →
Also registered at 150 Valpreda RD
A shared address usually means a shared clinic or building; it does not show who employs whom.
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- Lynda Ariella, PHDClinical Psychologist1073518965
- Maria BanuelosCase Manager/Care Coordinator1720280589
Verify William Robert Mathias in five checks
- 1IdentityNPI record in CMS NPPESNPI lookupConfirmed in NPPES
- 2LicenseActive license and public ordersWhich California board licenses this profession
Search for license 59627Check the board - 3Other statesLicenses and actions elsewhereDocInfo (FSMB)Not checked
- 4ExclusionsMedicare and Medicaid bansHHS-OIG exclusion listNot checked
- 5CertificationBoard certificationABMS AOA NCCPA AANPNot checked
59% fewer Medicare Part D claims than the average physician assistant in 2024
337 Medicare Part D claims for 114 beneficiaries, against an average of 830 among the 101,058 providers of this specialty who prescribed in Part D.
Most prescribed
- Levothyroxine Sodium27 claims
- Amlodipine Besylate14 claims
- Metformin Hcl14 claims
- Lisinopril13 claims
- Losartan Potassium12 claims
- Rosuvastatin Calcium12 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.
Industry payments in 2024: $223.91
9 payments; by number, the most common kind was food and beverage; the largest payer was Lilly USA, LLC. The 64,719 providers of this specialty with any payment received $841.65 on average. Payments are reported by manufacturers, not by the provider, and are not a sign of wrongdoing.
Source: CMS Open Payments, program year 2024 (openpaymentsdata.cms.gov); average among providers of this specialty with at least one payment.
Bills Medicare through one group practice
- Neighborhood HealthcareEscondido, CA
Source: CMS Doctors and Clinicians National Downloadable File (the group practices a clinician bills Medicare through) (data.cms.gov).
William Robert Mathias among 14,451 physician assistant records in California
William Robert Mathias, PA-C is one of 14,451 physician assistant records with a practice address in California. 75% of them appear in a Medicare file (Part D prescribing, MIPS, Open Payments or Medicare group billing); this one does. Its NPI, issued in 2008, is newer than 22% of them.
- NPI issued2008 · 22% of these records are older, 75% newer
- In a Medicare fileYes · 75% of these records are
- In the CMS Doctors and Clinicians fileYes · 50% of these records are
- Graduated2022 · median 2018 among the 7,214 with a school on file
- Record last updated2023 · 40% of these records were not updated in five years or more
Source: CMS NPPES, file of Aug 9, 2026, every record with primary taxonomy 363A00000X and a California practice address; Medicare files: CMS Part D Prescribers 2024, MIPS 2023, Open Payments 2024, Doctors and Clinicians (data.cms.gov).
26 physician assistant records list a practice address in San Marcos
They are 26 of the 1,985 NPPES records with a practice address in San Marcos, and 14,451 physician assistant records in California.
All 14,451 in California → Every provider in San Marcos → Physician Assistant nationwide →
The 8 physician assistant records with the nearest ZIP codes
- Geraldine Dodge, PASan Marcos, CA 920691639335771
- Meredith Heidenfeld, PA-CSan Marcos, CA 920691417954108
- Miriam Hernandez, PASan Marcos, CA 920691457903700
- Gabriela Juache-Velasco, PA-CSan Marcos, CA 920691043830763
- Sarah Kay, PASan Marcos, CA 920691538634209
- Matthew Kosel, PA-CSan Marcos, CA 920691316947302
- Jennifer Levine, PHYSICIAN ASSISTANT-San Marcos, CA 920691316109614
- Jennifer Montgomery, PA-CSan Marcos, CA 920691568658698
Common questions
What is William Robert Mathias, PA-C's NPI number?
William Robert Mathias, PA-C's National Provider Identifier (NPI) is 1285806323, issued on Mar 28, 2008. An NPI identifies a provider in billing; it is not a license.
Where is William Robert Mathias, PA-C located?
The NPPES record lists a practice address at 150 Valpreda RD, San Marcos, CA, 92069. Phone: (760) 736-6767. Providers update this record themselves, so call before visiting.
How can I verify William Robert Mathias, PA-C's license?
NPPES lists California license number 59627, as entered by the provider. Search the California board that licenses this profession; the NPPES record confirms identity only.
How much does William Robert Mathias, PA-C prescribe under Medicare Part D?
In 2024, William Robert Mathias, PA-C had 337 Medicare Part D claims for 114 beneficiaries; the average among physician assistant prescribers was 830. 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.