Mark Tsai, M.D.
NPI 1225033111 · Internal Medicine Physician · Paramount, CA
Enrolled with Medicare as Practitioner - Internal Medicine · source: CMS PECOS Public Provider Enrollment (2026.04.01)
Mark Tsai, M.D. is a Internal Medicine Physician provider in Paramount, CA (NPI 1225033111).
Provider details
- NPI number
- 1225033111
- Entity type
- Individual
- Primary specialty
- Internal Medicine PhysicianAllopathic & Osteopathic Physicians
- Credential
- M.D.
- Sex
- Male
- Sole proprietor
- Yes
- License
- A81875 (CA)
Specialties & taxonomies
Allopathic & Osteopathic Physicians
Profile Score
A profile completeness & documented-activity index — NOT a quality, outcomes, or patient-satisfaction rating.
- Registry tenure25% of score
21 yrs in NPPES registry
- Profile completeness25% of score
100% of core fields populated
- Practice footprint15% of score
1 documented practice location
- Medicare service volume (vs. specialty peers)25% of score
933 Medicare services, 2024 (ranked within specialty)
- Open Payments transparency10% of score
Has Open Payments disclosures (2024)
Medicare volume is ranked against active providers in the same specialty. Signals a provider has no public data for (e.g. Medicare claims) are left out of the score entirely — never counted as zero — so providers without that data are not penalized. See the full formula and weights in our .
What this provider does (Medicare)
Based on Medicare fee-for-service claims, 2024; not all care is captured.
| Service (HCPCS) | Medicare services | Typical Medicare-allowed (2024) |
|---|---|---|
| Established Patient Office Or Other Outpatient Visit With Low Level OD Decision Making, If Using Time, 20 Minutes Or More99213 | 401 | $99 |
| Brief Communication Technology-Based Service, E.g. Virtual Check-In, By a Physician Or Other Qualified Health Care Professional Who Can Report Evaluation and Management Services, Provided to an Established Patient, Not Originating From a Related E/M ServicG2012 | 223 | $15 |
| Established Patient Office Or Other Outpatient Visit With Straightforward Medical Decision Making, If Using Time, 10 Minutes Or More99212 | 142 | $62 |
| Annual Wellness Visit, Includes a Personalized Prevention Plan of Service (pps), Subsequent VisitG0439 | 68 | $139 |
| Administration of Influenza Virus VaccineG0008 | 64 | $29 |
| Established Patient Office Or Other Outpatient Visit With Moderate Level of Decision Making, If Using Time, 30 Minutes Or More |
What this provider prescribes (Medicare Part D)
Top drugs by Medicare Part D claim volume, 2024 · 147 distinct drugs on file.
| Drug | Part D claims (2024) | Beneficiaries |
|---|---|---|
| Atorvastatin Calcium | 445 | 132 |
| Metformin Hcl | 436 | 118 |
| Amlodipine Besylate | 397 | 116 |
| Losartan Potassium | 266 | 81 |
| Albuterol Sulfatebrand: Albuterol Sulfate Hfa | 248 | 68 |
| Omeprazole | 239 | 82 |
Transparency — industry payments
Based on CMS Open Payments, 2024; not all care is captured.
$1,842 across 64 records (Open Payments 2024)
Open Payments discloses payments and transfers of value (meals, travel, consulting, research, royalties) from drug and device makers to providers. This is a transparency signal, not a verdict — such payments are legal and common, and their presence is neither an endorsement nor a criticism. Source: CMS Open Payments, program year 2024.
Practice location
Mailing address
Registry dates
- Enumerated
- 2005-06-16
- Last updated
- 2017-04-03
Frequently asked questions
- What is Mark Tsai's NPI number?
- Mark Tsai's National Provider Identifier (NPI) is 1225033111, a unique 10-digit ID issued by CMS for use in standard healthcare transactions.
- What is Mark Tsai's specialty?
- Mark Tsai is listed in the NPPES registry with a primary specialty of Internal Medicine Physician (Allopathic & Osteopathic Physicians).
- Where is Mark Tsai located?
- Mark Tsai's practice location on file with NPPES is 16415 Colorado Ave, Paramount, CA 90723-5035.
- What is Mark Tsai's phone number?
- The practice phone number listed in the NPPES registry for Mark Tsai is (562) 634-6341.
- Does Mark Tsai accept Medicare?
- Mark Tsai is approved to bill Medicare according to CMS PECOS enrollment data (2026.04.01). Confirm current participation with the provider before scheduling.
- Is Mark Tsai's NPI active?
- Yes — Mark Tsai's NPI (1225033111) is active in the NPPES registry as of the last update on 2017-04-03.
Source: CMS NPPES Data Dissemination (June 2026). NPI Central is not affiliated with CMS. Data is provided as-is from the public registry.