NPPES file of Aug 9, 2026

Aaron Pessl, M.D.

Emergency Medicine Physician · Hayward, CA

Aaron Pessl, M.D. is an emergency medicine physician with a practice address in Hayward, California, and NPI 1063425072, issued on Aug 14, 2006. Check the license (California A89998, as entered in NPPES) on the Medical Board of California; the Medicare figures below come from public CMS files.

Record from CMS NPPES, file of Aug 9, 2026 · Medicare files 2024 · method · Verify with CMS →

NPPES recordNPPES file of Aug 9, 2026
1063425072
Name
Aaron Pessl
Credential
M.D.
Primary taxonomy
Emergency Medicine Physician 207P00000X
License number
A89998 CA
Self-reported in NPPES; status is on the state search
Practice location
27400 Hesperian Blvd, Hayward, CA 94545
Phone
(510) 784-4525
Enumerated
Aug 14, 2006
Record last updated
Dec 9, 2021 (not updated in 5 years: call before relying on the address or phone)
Medicaid ID
00A899980 CA
Medicare enrollment
Enrolled (PECOS I20051223000205); accepts Medicare assignment
Medical or professional school
Tulane University School Of Medicine, 2003
Entity
Type 1 · individual
Public record from CMS NPPES (open it on the CMS NPI Registry). Enrollment, assignment, school and telehealth: CMS Doctors and Clinicians file, Aug 2026. A record is not a license: verify it with the state board.
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8 nearest emergency medicine physician records → All 7,751 in California → Look up another NPI →

Also registered at 27400 Hesperian Blvd

A shared address usually means a shared clinic or building; it does not show who employs whom.

  1. Lyn Aborn, MDEmergency Medicine Physician1891873659
  2. Ahmed Alkoraishi, MDColon & Rectal Surgery Physician1609954478
  3. David Anderson, MDInternal Medicine Physician1659459410
  4. Eric Anderson, MDEmergency Medicine Physician1417035262
  5. Joel Angel, M.D.Hospitalist Physician1669644571
  6. Marc Anker, MDObstetrics & Gynecology Physician1376621128

Verify Aaron Pessl in five checks

  1. 1IdentityNPI record in CMS NPPESNPI lookupConfirmed in NPPES
  2. 2LicenseActive license and public ordersMedical Board of California
    Search for license A89998    Check the board
  3. 3Other statesLicenses and actions elsewhereDocInfo (FSMB)Not checked
  4. 4ExclusionsMedicare and Medicaid bansHHS-OIG exclusion listNot checked
  5. 5CertificationBoard certificationABMS AOA NCCPA AANPNot checked
Open the California license search

PlainDoctor does not match the HHS-OIG exclusion list to individual records: most entries carry no NPI. Search the OIG exclusion list by name.

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3% more Medicare Part D claims than the average emergency medicine physician in 2024

232 Medicare Part D claims for 146 beneficiaries, against an average of 226 among the 54,106 providers of this specialty who prescribed in Part D. Brand-name drugs were 8% of claims. 28 claims were for opioids.

  1. Aaron Pessl232
  2. Specialty average226

Most prescribed

  1. Ondansetron Odt29 claims
  2. Cefpodoxime Proxetil25 claims
  3. Prednisone25 claims
  4. Albuterol Sulfate Hfa17 claims
  5. Oxycodone-Acetaminophen16 claims
  6. Ibuprofen14 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

  1. Permanente Medical Group IncSan Leandro, CA

Source: CMS Doctors and Clinicians National Downloadable File (the group practices a clinician bills Medicare through) (data.cms.gov).

Aaron Pessl among 7,751 emergency medicine physician records in California

Aaron Pessl, M.D. is one of 7,751 emergency medicine physician records with a practice address in California. 81% 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 4% of them.

  • NPI issued2006 · 4% of these records are older, 60% newer
  • In a Medicare fileYes · 81% of these records are
  • In the CMS Doctors and Clinicians fileYes · 59% of these records are
  • Graduated2003 · median 2011 among the 4,560 with a school on file
  • Record last updated2021 · 59% of these records were not updated in five years or more

Source: CMS NPPES, file of Aug 9, 2026, every record with primary taxonomy 207P00000X and a California practice address; Medicare files: CMS Part D Prescribers 2024, MIPS 2023, Open Payments 2024, Doctors and Clinicians (data.cms.gov).

26 emergency medicine physician records list a practice address in Hayward

They are 26 of the 3,993 NPPES records with a practice address in Hayward, and 7,751 emergency medicine physician records in California.

All 7,751 in California → Every provider in Hayward → Emergency Medicine Physician nationwide →

The 8 emergency medicine physician records with the nearest ZIP codes

  1. Lyn Aborn, MDHayward, CA 945451891873659
  2. Eric Anderson, MDHayward, CA 945451417035262
  3. Robert Blum, MDHayward, CA 945451730267592
  4. Jeremy Graff, M.DHayward, CA 945451669491429
  5. Shao-I Huang, D.O.Hayward, CA 945451215031455
  6. Tan Nguyen, M.D.Hayward, CA 945451437173754
  7. Lisa Pinsky, MDHayward, CA 945451831277680
  8. Julie Schwengels, MDHayward, CA 945451639257496

Common questions

What is Aaron Pessl, M.D.'s NPI number?

Aaron Pessl, M.D.'s National Provider Identifier (NPI) is 1063425072, issued on Aug 14, 2006. An NPI identifies a provider in billing; it is not a license.

Where is Aaron Pessl, M.D. located?

The NPPES record lists a practice address at 27400 Hesperian Blvd, Hayward, CA, 94545. Phone: (510) 784-4525. Providers update this record themselves, so call before visiting.

How can I verify Aaron Pessl, M.D.'s license?

NPPES lists California license number A89998, 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 Aaron Pessl, M.D. prescribe under Medicare Part D?

In 2024, Aaron Pessl, M.D. had 232 Medicare Part D claims for 146 beneficiaries; the average among emergency medicine physician prescribers was 226. 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.

Written with AI tools from the named public files; every figure is computed from those files (how it is made).

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.