Tze Lyn S. Tseeng, MD

Medicare activity in 2024

Official CMS public-use data for Tze Lyn S. Tseeng, 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.

Most frequent services

1. Emergency department visit with high level of medical decision making (99285)82 services
2. Routine electrocardiogram (ecg) using at least 12 leads with interpretation and report only (93010)79 services
3. New patient office or other outpatient visit with low level of medical decision making, if using time, 30 minutes or more (99203)71 services
4. Established patient office or other outpatient visit with moderate level of decision making, if using time, 30 minutes or more (99214)60 services
5. New patient office or other outpatient visit with moderate level of medical decision making, if using time, 45 minutes or more (99204)56 services

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 blood pressure75%
• High cholesterol75%
• Arthritis52%
• Diabetes36%
• Ischemic heart disease32%
• Depression30%

Hospitals where Tze Lyn S. Tseeng works

Medicare's Facility Affiliation Data lists Tze Lyn S. Tseeng 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.

• AHMC Anaheim Regional Medical CenterAnaheim, CA · Acute Care Hospital · Medicare rating: 4 of 5 stars · Emergency services: listed by Medicare · CCN 050226
• Catalina Island Medical CenterAvalon, CA · Critical Access Hospital · Emergency services: listed by Medicare · CCN 051307
• UCI Health-OrangeOrange, CA · Acute Care Hospital · Medicare rating: 4 of 5 stars · Emergency services: listed by Medicare · CCN 050348

Practice locations

Addresses where Tze Lyn S. Tseeng is enrolled with Medicare (CMS data updated October 2, 2026).

• 100 Falls Canyon RdAvalon, CA 90704 (310) 510‑0700
• 101 the City Dr SOrange, CA 92868 (714) 456‑7004
• 1111 W La Palma AveAnaheim, CA 92801 (951) 898‑0823

Group practices

Medicare enrollment lists Tze Lyn S. Tseeng as a member of these groups (CMS data updated October 2, 2026).

• Regents of the University of129 clinicians in the group
• Avalon Medical Development Corporation30 clinicians in the group
• Anaheim Emergency Medical Group21 clinicians in the group

Specialties

• Emergency Medicineprimary

Find other Emergency Medicine doctors in California →

Other emergency medicine doctors in Avalon

Clinicians with the same Medicare primary specialty in Avalon, CA — not a recommendation.

• Megan E. Guy, MD
• Berhane Hagos, MD
• Adam Sauer, MD
• Lauren E. Lamparter, MD
• Inna Shniter, MD
• John C. Fox, MD
• Matthew Byrnes, MD
• Joshua K. Livingston, MD

All emergency medicine doctors in Avalon →

Other clinicians in Regents of the University of

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

• Mina Masri, DO
• Gihan K. Wetzel, DO
• Michael J. Lambing, DO
• Mark I. Langdorf, MD
• Shannon L. Toohey, MD
• Kathleen G. Ahn, NP

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