Ahdad Ziyar, MD

Medicare activity in 2024

Official CMS public-use data for Ahdad Ziyar, data year 2024 (released May 21, 2026). It covers Original Medicare (fee-for-service) patients only, not Medicare Advantage or other insurance. It shows volume, not quality or outcomes. CMS hides any count of 10 or fewer patients.

Chronic conditions among these patients

Share of this clinician’s Original Medicare patients with each condition, as published by CMS (it describes the patients, not the care given).

• High cholesterol61%
• High blood pressure57%
• Asthma43%

Hospitals where Ahdad Ziyar works

Medicare's Facility Affiliation Data lists Ahdad Ziyar at these hospitals (updated October 2, 2026). Each hospital page shows its address, phone, emergency services, Medicare rating and all its clinicians. Star rating and emergency services: Hospital General Information (CMS), data updated October 26, 2026.

• Kaiser Foundation Hospital - DowneyDowney, CA · Acute Care Hospital · Medicare rating: 4 of 5 stars · Emergency services: not listed by Medicare · CCN 050139

Practice locations

Addresses where Ahdad Ziyar is enrolled with Medicare (CMS data updated October 2, 2026).

• 10725 International DrRancho Cordova, CA 95670 (916) 631‑3000
• 801 N Tustin Ave, Suite 605Santa Ana, CA 92705 (714) 584‑9930

Group practices

Medicare enrollment lists Ahdad Ziyar as a member of this group (CMS data updated October 2, 2026).

• Permanente Medical Group Inc10,996 clinicians in the group

Specialties

• Allergy/Immunologyprimary
• Internal Medicinealso

Find other Allergy/Immunology doctors in California →

Other allergist and immunologists in California

Clinicians with the same Medicare primary specialty in California — not a recommendation.

• Louanne M. Tourangeau, MD
• Cindy T. Nguyen Delsignore, MD
• Neema Izadi, MD
• Jonathan Corren, MD
• Imran Junaid, MD
• William G. Harris, MD
• Joseph M. Young, MD
• Nataliya M. Kushnir, MD

All allergist and immunologists in California →

Other clinicians in Permanente Medical Group Inc

Medicare enrollment lists these clinicians in the same group practice — not a recommendation.

• David R. Collman, DPM
• Vang Kou Khang, MD
• Michael T. Caulfield, MD
• Sreedevi G. Thamarasseril, MD
• Ravi K. Aggu Sher, MD
• Lynda X. Yu, MD

Clinician information

Most corrections must be made at the source: clinicians update their NPI Registry record (NPPES) and their Medicare enrollment (PECOS); this page follows the next data release.

Sources

1. Facility Affiliation Data — Centers for Medicare & Medicaid Services (CMS), data updated October 2, 2026, retrieved October 29, 2026
2. Hospital General Information — CMS, data updated October 26, 2026, retrieved November 13, 2026
3. National Downloadable File (Doctors and Clinicians) — CMS, data updated October 2, 2026, retrieved October 29, 2026
4. Medicare Physician & Other Practitioners - by Provider — CMS, data year 2024, released May 21, 2026; Medicare Physician & Other Practitioners - by Provider and Service
5. NPI Registry — U.S. Department of Health and Human Services (NPPES), the clinician’s official record
6. Medicare Care Compare — official Medicare tool to look up clinicians