Mon-Ta Tsai, M.D.
NPI 1427019231 · Internal Medicine Physician · Mission Viejo, CA
Enrolled with Medicare as Practitioner - Internal Medicine · source: CMS PECOS Public Provider Enrollment (2026.04.01)
Mon-Ta Tsai, M.D. is a Internal Medicine Physician provider in Mission Viejo, CA (NPI 1427019231).
Provider details
- NPI number
- 1427019231
- Entity type
- Individual
- Primary specialty
- Internal Medicine PhysicianAllopathic & Osteopathic Physicians
- Credential
- M.D.
- Sex
- Male
- License
- A65382 (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
20 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
771 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 Moderate Level of Decision Making, If Using Time, 30 Minutes Or More99214 | 359 | $138 |
| Annual Wellness Visit, Includes a Personalized Prevention Plan of Service (pps), Subsequent VisitG0439 | 84 | $140 |
| Annual Depression Screening, 5 to 15 MinutesG0444 | 81 | $21 |
| Established Patient Office Or Other Outpatient Visit With Low Level OD Decision Making, If Using Time, 20 Minutes Or More99213 | 66 | $99 |
| Administration of Influenza Virus VaccineG0008 | 50 | $34 |
| Established Patient Office Or Other Outpatient Visit With High Level of Medical Decision Making, If Using Time, 40 Minutes Or More99215 |
What this provider prescribes (Medicare Part D)
Top drugs by Medicare Part D claim volume, 2024 · 67 distinct drugs on file.
| Drug | Part D claims (2024) | Beneficiaries |
|---|---|---|
| Losartan Potassium | 366 | 101 |
| Amlodipine Besylate | 323 | 90 |
| Rosuvastatin Calcium | 318 | 97 |
| Atorvastatin Calcium | 269 | 82 |
| Metformin Hcl | 165 | 50 |
| Tamsulosin Hcl | 134 | 41 |
| Metoprolol Succinate |
Transparency — industry payments
Based on CMS Open Payments, 2024; not all care is captured.
$175 across 3 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
- 2006-03-31
- Last updated
- 2007-07-08
Frequently asked questions
- What is Mon-Ta Tsai's NPI number?
- Mon-Ta Tsai's National Provider Identifier (NPI) is 1427019231, a unique 10-digit ID issued by CMS for use in standard healthcare transactions.
- What is Mon-Ta Tsai's specialty?
- Mon-Ta Tsai is listed in the NPPES registry with a primary specialty of Internal Medicine Physician (Allopathic & Osteopathic Physicians).
- Where is Mon-Ta Tsai located?
- Mon-Ta Tsai's practice location on file with NPPES is 25982 Pala, Mission Viejo, CA 92691-6719.
- What is Mon-Ta Tsai's phone number?
- The practice phone number listed in the NPPES registry for Mon-Ta Tsai is (949) 588-0051.
- Does Mon-Ta Tsai accept Medicare?
- Mon-Ta Tsai is approved to bill Medicare according to CMS PECOS enrollment data (2026.04.01). Confirm current participation with the provider before scheduling.
- Is Mon-Ta Tsai's NPI active?
- Yes — Mon-Ta Tsai's NPI (1427019231) is active in the NPPES registry as of the last update on 2007-07-08.
Source: CMS NPPES Data Dissemination (June 2026). NPI Central is not affiliated with CMS. Data is provided as-is from the public registry.