2026 NPPES data Internal Medicine Physician NPI 1558523670 M.D., M.S.
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TONY TSENG, M.D., M.S.

Internal Medicine Physician in SOUTH GATE, California. CMS National Plan and Provider Enumeration System profile including specialty classification, practice address, and Medicare prescribing data when reported.

Federal data — no proprietary rating. PlainDoctor publishes the actual CMS NPPES and Medicare records — NPI registration, specialty, practice location, and prescribing data — without a composite score or editorial opinion on top. Every field traces to a federal source.
Prescribing volume
5K
Medicare Part D claims · 265 beneficiaries · Internal Medicine Physician avg: 3K
Generic prescribing
85%
generic claims · 15% brand-name · higher generic rates reduce patient out-of-pocket costs
Industry payments
$325.09
14 payments · CMS Open Payments (Sunshine Act)

What the federal data shows

TONY TSENG, M.D., M.S. filed 5,155 Medicare Part D claims in 2023 as a Internal Medicine Physician in SOUTH GATE, California, prescribing 85% generic.

5K
Part D claims, 2023
85%
generic prescribing
Likely
board-certified (heuristic)

Every figure on this page comes straight from federal CMS records (NPPES, Medicare Part D, MIPS, Open Payments) — no proprietary rating or editorial opinion is applied.

TONY TSENG, M.D., M.S.'s Medicare Part D volume vs every U.S. prescriber

Total Medicare Part D claims, 2023 — across all CMS prescribers nationally

5,155 Top 6% higher than 94% of 1,370,886 prescribers

0–200: 670,926 prescribers (49%). Below this entry. 200–400: 182,923 prescribers (13%). Below this entry. 400–600: 90,619 prescribers (7%). Below this entry. 600–800: 56,224 prescribers (4%). Below this entry. 800–1,000: 40,919 prescribers (3%). Below this entry. 1,000–1,200: 31,827 prescribers (2%). Below this entry. 1,200–1,400: 26,224 prescribers (2%). Below this entry. 1,400–1,600: 21,710 prescribers (2%). Below this entry. 1,600–1,800: 19,072 prescribers (1%). Below this entry. 1,800–2,000: 16,451 prescribers (1%). Below this entry. 2,000–2,200: 213,991 prescribers (16%). This entry sits in this band. This provider 0 2K+ every Part D prescriber (claims/yr), bucketed by value

Each bar is a band; taller bars hold more prescribers. The dashed line + filled bar mark this entry. Hover or tap any bar for its full count, share, and where it sits relative to this entry.

Source CMS Medicare Part D Prescriber Public Use File · 2023

Board certification likely (heuristic — not verified)

TONY TSENG, M.D., M.S. practices in an ABMS-board-eligible specialty and shows active CMS Medicare participation + 1 hospital affiliation — signals consistent with board-certified status. For verified board certification, see CertificationMatters.org (the official ABMS public lookup).

What does the federal data show about TONY TSENG, M.D., M.S.?

Quality data not reported

NPI registry status

Active

Issued 06/30/2008

NPI 1558523670

Primary specialty

Internal Medicine Physician

High-volume

172,858 US NPIs in this specialty

Medicare Part D claims

5,155 90% vs specialty avg

2023 prescription claims

Specialty avg: 2,716

Specialty distribution in California

How Internal Medicine Physician compares to other specialties among California providers

California providers

Internal Medicine Physician share within California

1. Internal Medicine Physician42%2. Internal medicine21%3. Family medicine17%4. Surgical12%5. Pediatric8%
Internal Medicine Physician share within California

Specialty board-certification context

Estimated specialty board-certified rate — Internal Medicine Physician (ABMS / AOA reference)

Quality data not reported
Est. board-certified rate
78%
Internal Medicine Physician ABMS/AOA estimate

Est. board-certified rate (Internal Medicine Physician) — ABMS / AOA estimate

0%100%78%
Est. board-certified rate (Internal Medicine Physician) — ABMS / AOA estimate

The Merit-based Incentive Payment System (MIPS) scores providers 0–100 across four performance categories: Quality, Cost, Promoting Interoperability, and Improvement Activities, weighted under 42 CFR §414.1380. Reporting is voluntary for many small practices, so absence of a MIPS score is not a quality signal.

Board certification through an ABMS or AOA member board signals voluntary post-licensure examination plus continuous Maintenance of Certification cycles. Verify any individual provider's status through certificationmatters.org (ABMS) or osteopathic.org (AOA).

TONY TSENG, M.D., M.S. appears in the CMS NPPES registry as a Internal Medicine Physician provider holding M.D., M.S. credentials at 3224 SANTA ANA ST, SOUTH GATE, CA, 90280, with a listed phone of (323) 763-1300. NPI 1558523670 was issued on 06/30/2008. Because NPPES data is self-reported by the provider and refreshed monthly, the address, phone, and specialty reflect what TSENG most recently submitted to CMS rather than a vetted directory listing, which is why patients should always confirm the practice is still at this location before scheduling.

Medicare Part D records for calendar year 2023 show 5,155 prescription claims written by this provider, covering 265 Medicare beneficiaries and totaling roughly $567K in drug spend, split 15% brand-name and 85% generic by claim count, with an opioid prescribing rate of 3.7%. These figures capture only Medicare Part D — commercial insurance, Medicaid, and cash-pay prescriptions are not included, and any drug-beneficiary cell under 11 is suppressed by CMS for patient privacy.

Internal Medicine Physician is a high-volume specialty nationwide, with 172,858 enrolled providers across 56 states and an average of 2,716 Part D claims per prescriber, so the context for interpreting these metrics differs meaningfully from a primary-care baseline. Important: PlainDoctor is a directory of publicly available government data, not medical advice, a malpractice database, or a quality rating. Inclusion here does not imply a recommendation, and absence of complaints or sanctions on this page does not mean none exist — always verify credentials through the NPPES NPI Registry, your state medical board, and the ABMS or AOA before making healthcare decisions.

Practice Address

3224 SANTA ANA ST
SOUTH GATE, CA 90280

Provider Details

NPI 1558523670
Specialty Internal Medicine Physician
Credentials M.D., M.S.
Gender Male
NPI Issued 06/30/2008

Hospital and facility affiliations

Facilities where TONY TSENG, M.D., M.S. bills Medicare from. Star ratings (1-5) are CMS Hospital Compare's "Hospital overall rating" — a composite of mortality, readmission, patient experience, safety, timely care, and efficient use of medical imaging measures. Source: CMS Care Compare.

PROHEALTH PARTNERS, A MEDICAL GROUP
LONG BEACH, CA

Affiliations sourced from CMS Doctors and Clinicians National Downloadable File; hospital ratings from CMS Hospital General Information dataset (cross-referenced by facility name + state).

Industry payments received (2024) — CMS Open Payments transparency data

The federal Physician Payments Sunshine Act (part of the Affordable Care Act) requires drug and medical-device manufacturers + group purchasing organizations to publicly report payments and other transfers of value to physicians and teaching hospitals. The data below covers 2024 for TONY TSENG, M.D., M.S.. Source: openpaymentsdata.cms.gov.

Total received

$325

Largest payer

Salix Pharmaceuticals, a division of Bausch Health US, LLC

Most common payment type

Food and Beverage

Industry payments are not necessarily indicators of bias — they include research funding, consulting fees for evidence-based work, royalties for inventions, food at conferences, and similar items. The disclosure exists for transparency. Read our methodology for how we interpret this data.

License & disciplinary context — California MBC 2023 annual report

Aggregate state board data only — NOT a determination of any individual provider's status. The figures below describe statewide disciplinary activity across all ~150K California medical licensees in 2023 — they are NOT specific to TONY TSENG, M.D., M.S.. To verify TONY TSENG, M.D., M.S.'s current license status, search the MBC public license lookup directly, or check the Federation of State Medical Boards (FSMB) verification service.

576
Total board actions, California 2023
Across 556 cases
3.84
Actions per 1,000 licensees
California statewide rate
probation
Most common action type
186 cases

MBC publishes annual disciplinary statistics as part of public-record reporting under each state's Administrative Procedure Act. See the full breakdown by action type and year on the California disciplinary trends page. Cross-checked against FSMB U.S. Medical Regulatory Trends.

Brand vs generic prescribing mix · Typical

TONY TSENG, M.D., M.S. — brand share 15.0%
Specialty average (est.)

15% brand-name claims vs 85% generic, on 5,155 2023 Medicare Part D claims.

The federal Medicare Part D Generic Dispensing Rate national benchmark sits near 90% generic / 10% brand for primary-care prescribers, per CMS Office of the Actuary 2024 estimates. Higher brand share is common in specialty prescribing where generic equivalents are not available.

Medicare Part D Prescribing Data

CMS Medicare Part D prescriber-level data for calendar year 2023.

5,155
Total Claims
$567K
Total Drug Cost
265
Medicare Beneficiaries

Prescribing Breakdown

30-Day Fills
9,865
Total Day Supply
279,603
Brand vs Generic
15% brand / 85% generic
Brand Drug Cost
$410K
Generic Drug Cost
$150K
Opioid Claims
192 (3.7% rate)
Antibiotic Claims
213

Patient Demographics

Average Patient Age
74.0 years
Avg HCC Risk Score
2.52
Gender Split
59% female / 41% male
Age Distribution
<65: 44, 65-74: 86, 75-84: 85, 85+: 50

Top Prescribed Drugs (Medicare Part D)

Top drugs by claim count for calendar year 2023. Based on Medicare Part D data only.

What TONY TSENG, M.D., M.S. prescribes most

Top Medicare Part D drugs by claim count, 2023

claims
Source CMS Medicare Part D Prescriber Public Use File As of 2023
Drug Claims
Atorvastatin Calcium
321
Diclofenac Sodium
189
Omeprazole
178
Losartan Potassium
170
Metformin Hcl
166
Gabapentin
154
Furosemide
151
Lisinopril
116
Amlodipine Besylate
114
Lidocaine
95

* Counts below 11 are suppressed by CMS for patient privacy. Generic names shown where available from CMS Part D data.

Internal Medicine Physician Overview

How TONY TSENG, M.D., M.S. fits within the Internal Medicine Physician landscape nationally.

172,858
Internal Medicine Physician Providers in US
56
States with Internal Medicine Physician
2,716
Avg Claims per Provider

TONY TSENG, M.D., M.S.'s 5,155 claims are above the specialty average of 2,716.

Nearby Internal Medicine Physician Providers in California

Other clinicians with the same primary specialty enrolled in California, drawn from the same CMS NPPES roster as TSENG.

Compare Internal Medicine Physician nationally: see state-by-state distribution →

Frequently Asked Questions

What is TONY TSENG, M.D., M.S.'s specialty?
TONY TSENG, M.D., M.S. specializes in Internal Medicine Physician and practices in SOUTH GATE, California. Credentials: M.D., M.S..
How much does TONY TSENG, M.D., M.S. prescribe under Medicare Part D?
In 2023, TONY TSENG, M.D., M.S. wrote 5,155 Medicare Part D claims totaling $567K in drug costs for 265 beneficiaries.
Where is TONY TSENG, M.D., M.S. located?
TONY TSENG, M.D., M.S. is located at 3224 SANTA ANA ST, SOUTH GATE, CA, 90280. Phone: (323) 763-1300.
What is TONY TSENG, M.D., M.S.'s NPI number?
TONY TSENG, M.D., M.S.'s National Provider Identifier (NPI) is 1558523670, issued on 06/30/2008.
Does TONY TSENG, M.D., M.S. prescribe more brand-name or generic drugs?
TONY TSENG, M.D., M.S.'s prescribing is 15% brand-name and 85% generic drugs by claim count, with $410K in brand drug costs.
Does TONY TSENG, M.D., M.S. prescribe opioids?
Yes, TONY TSENG, M.D., M.S. had 192 opioid claims in 2023 with an opioid prescribing rate of 3.7%.
How many Internal Medicine Physician providers are there in the US?
There are 172,858 Internal Medicine Physician providers across 56 states in the US. The average Internal Medicine Physician provider writes 2,716 Medicare Part D claims per year.
What drugs does TONY TSENG, M.D., M.S. prescribe most often?
Based on 2023 Medicare Part D data, TONY TSENG, M.D., M.S.'s most frequently prescribed drugs include Atorvastatin Calcium, Diclofenac Sodium, Omeprazole. This reflects Medicare Part D prescriptions only and does not include commercial insurance or other payer types.
Does TONY TSENG, M.D., M.S. accept Medicare?
TONY TSENG, M.D., M.S. appears in CMS Medicare data with 5,155 Part D claims and 265 Medicare beneficiaries in 2023. Contact the provider's office directly to confirm current Medicare enrollment and accepted plans.
How can I verify TONY TSENG, M.D., M.S.'s credentials?
TONY TSENG, M.D., M.S.'s NPI is 1558523670 with credentials M.D., M.S.. You can verify this through the NPPES NPI Registry, check state medical board records, and confirm board certification through the ABMS or AOA.

Data Sources

Provider Directory
CMS National Plan and Provider Enumeration System (NPPES), download.cms.gov/nppes, updated monthly. Contains NPI, specialty, credentials, and practice location.
Specialty Classification
NUCC Health Care Provider Taxonomy (nucc.org), the industry standard for classifying provider specialties in Medicare and Medicaid billing.
Prescribing Data
CMS Medicare Part D Prescriber Public Use File (2023). Includes claims, drug costs, beneficiaries, and opioid prescribing rates.
Limitations
Provider data is self-reported to CMS. Prescribing data reflects Medicare Part D only and does not include commercial insurance, Medicaid, or cash prescriptions. Claims below 11 beneficiaries are suppressed by CMS for privacy.

See our complete data methodology for details on how we collect and process government data.

Data as of April 2026 (NPPES) / 2023 (Medicare Part D). Source: Centers for Medicare & Medicaid Services (CMS).

Disclaimer: Data from CMS NPPES and Medicare Part D. PlainDoctor does not rate or rank providers. Provider information is self-reported and may not be current. Always verify information directly with the provider. About · Methodology