2026 NPPES data Adult Health Nurse Practitioner NPI 1255792875 NURSE PRACTITIONER
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TAMMY CHEN, NURSE PRACTITIONER

Adult Health Nurse Practitioner in FULLERTON, 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
1K
Medicare Part D claims · 214 beneficiaries · Adult Health Nurse Practitioner avg: 1K
Generic prescribing
99%
generic claims · 1% brand-name · higher generic rates reduce patient out-of-pocket costs
Industry payments
$16.21
1 payments · CMS Open Payments (Sunshine Act)

What the federal data shows

TAMMY CHEN, NURSE PRACTITIONER filed 1,467 Medicare Part D claims in 2023 as a Adult Health Nurse Practitioner in FULLERTON, California, prescribing 99% generic.

1K
Part D claims, 2023
99%
generic prescribing
$16.21
industry payments (Sunshine Act)

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.

TAMMY CHEN, NURSE PRACTITIONER's Medicare Part D volume vs every U.S. prescriber

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

1,467 Top 20% higher than 80% 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%). This entry sits in this band. 1,600–1,800: 19,072 prescribers (1%). Above this entry. 1,800–2,000: 16,451 prescribers (1%). Above this entry. 2,000–2,200: 213,991 prescribers (16%). Above this entry. 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

What does the federal data show about TAMMY CHEN, NURSE PRACTITIONER?

Quality data not reported

NPI registry status

Active

Issued 03/09/2016

NPI 1255792875

Primary specialty

Adult Health Nurse Practitioner

Mid-sized

29,492 US NPIs in this specialty

Medicare Part D claims

1,467 22% vs specialty avg

2023 prescription claims

Specialty avg: 1,201

Specialty distribution in California

How Adult Health Nurse Practitioner compares to other specialties among California providers

California providers

Adult Health Nurse Practitioner share within California

1. Adult Health Nurse Practitioner42%2. Internal medicine21%3. Family medicine17%4. Surgical12%5. Pediatric8%
Adult Health Nurse Practitioner share within California

Specialty board-certification context

Estimated specialty board-certified rate — Adult Health Nurse Practitioner (ABMS / AOA reference)

Quality data not reported
Est. board-certified rate
78%
Adult Health Nurse Practitioner ABMS/AOA estimate

Est. board-certified rate (Adult Health Nurse Practitioner) — ABMS / AOA estimate

0%100%78%
Est. board-certified rate (Adult Health Nurse Practitioner) — 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).

TAMMY CHEN, NURSE PRACTITIONER appears in the CMS NPPES registry as a Adult Health Nurse Practitioner provider holding NURSE PRACTITIONER credentials at 150 LAGUNA RD STE A, FULLERTON, CA, 92835, with a listed phone of (714) 525-8822. NPI 1255792875 was issued on 03/09/2016. Because NPPES data is self-reported by the provider and refreshed monthly, the address, phone, and specialty reflect what CHEN 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 1,467 prescription claims written by this provider, covering 214 Medicare beneficiaries and totaling roughly $33K in drug spend, split 1% brand-name and 99% generic by claim count, with an opioid prescribing rate of 27.7%. 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.

Adult Health Nurse Practitioner is a mid-sized specialty nationwide, with 29,492 enrolled providers across 55 states and an average of 1,201 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

150 LAGUNA RD STE A
FULLERTON, CA 92835

Provider Details

NPI 1255792875
Specialty Adult Health Nurse Practitioner
Credentials NURSE PRACTITIONER
Gender Female
NPI Issued 03/09/2016

Hospital and facility affiliations

Facilities where TAMMY CHEN, NURSE PRACTITIONER 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.

HOAG CLINIC
NEWPORT 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 TAMMY CHEN, NURSE PRACTITIONER. Source: openpaymentsdata.cms.gov.

Total received

$16

Largest payer

Boston Scientific Corporation

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 TAMMY CHEN, NURSE PRACTITIONER. To verify TAMMY CHEN, NURSE PRACTITIONER'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 · Generic-heavy

TAMMY CHEN, NURSE PRACTITIONER — brand share 1.0%
Specialty average (est.)

1% brand-name claims vs 99% generic, on 1,467 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.

1,467
Total Claims
$33K
Total Drug Cost
214
Medicare Beneficiaries

Prescribing Breakdown

30-Day Fills
1,879
Total Day Supply
53,522
Brand vs Generic
1% brand / 99% generic
Brand Drug Cost
$820
Generic Drug Cost
$33K
Opioid Claims
407 (27.7% rate)

Patient Demographics

Average Patient Age
71.4 years
Avg HCC Risk Score
2.50
Gender Split
71% female / 29% male
Age Distribution
<65: 36, 65-74: 101, 75-84: 60, 85+: 17

Top Prescribed Drugs (Medicare Part D)

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

What TAMMY CHEN, NURSE PRACTITIONER 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
Gabapentin
300
Hydrocodone-Acetaminophen
Hydrocodone/Acetaminophen
247
Diclofenac Sodium
143
Tizanidine Hcl
133
Pregabalin
109
Cyclobenzaprine Hcl
89
Tramadol Hcl
81
Baclofen
69
Meloxicam
49
Duloxetine Hcl
48

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

Adult Health Nurse Practitioner Overview

How TAMMY CHEN, NURSE PRACTITIONER fits within the Adult Health Nurse Practitioner landscape nationally.

29,492
Adult Health Nurse Practitioner Providers in US
55
States with Adult Health Nurse Practitioner
1,201
Avg Claims per Provider

TAMMY CHEN, NURSE PRACTITIONER's 1,467 claims are above the specialty average of 1,201.

Nearby Adult Health Nurse Practitioner Providers in California

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

Compare Adult Health Nurse Practitioner nationally: see state-by-state distribution →

Frequently Asked Questions

What is TAMMY CHEN, NURSE PRACTITIONER's specialty?
TAMMY CHEN, NURSE PRACTITIONER specializes in Adult Health Nurse Practitioner and practices in FULLERTON, California. Credentials: NURSE PRACTITIONER.
How much does TAMMY CHEN, NURSE PRACTITIONER prescribe under Medicare Part D?
In 2023, TAMMY CHEN, NURSE PRACTITIONER wrote 1,467 Medicare Part D claims totaling $33K in drug costs for 214 beneficiaries.
Where is TAMMY CHEN, NURSE PRACTITIONER located?
TAMMY CHEN, NURSE PRACTITIONER is located at 150 LAGUNA RD STE A, FULLERTON, CA, 92835. Phone: (714) 525-8822.
What is TAMMY CHEN, NURSE PRACTITIONER's NPI number?
TAMMY CHEN, NURSE PRACTITIONER's National Provider Identifier (NPI) is 1255792875, issued on 03/09/2016.
Does TAMMY CHEN, NURSE PRACTITIONER prescribe more brand-name or generic drugs?
TAMMY CHEN, NURSE PRACTITIONER's prescribing is 1% brand-name and 99% generic drugs by claim count, with $820 in brand drug costs.
Does TAMMY CHEN, NURSE PRACTITIONER prescribe opioids?
Yes, TAMMY CHEN, NURSE PRACTITIONER had 407 opioid claims in 2023 with an opioid prescribing rate of 27.7%.
How many Adult Health Nurse Practitioner providers are there in the US?
There are 29,492 Adult Health Nurse Practitioner providers across 55 states in the US. The average Adult Health Nurse Practitioner provider writes 1,201 Medicare Part D claims per year.
What drugs does TAMMY CHEN, NURSE PRACTITIONER prescribe most often?
Based on 2023 Medicare Part D data, TAMMY CHEN, NURSE PRACTITIONER's most frequently prescribed drugs include Gabapentin, Hydrocodone-Acetaminophen, Diclofenac Sodium. This reflects Medicare Part D prescriptions only and does not include commercial insurance or other payer types.
Does TAMMY CHEN, NURSE PRACTITIONER accept Medicare?
TAMMY CHEN, NURSE PRACTITIONER appears in CMS Medicare data with 1,467 Part D claims and 214 Medicare beneficiaries in 2023. Contact the provider's office directly to confirm current Medicare enrollment and accepted plans.
How can I verify TAMMY CHEN, NURSE PRACTITIONER's credentials?
TAMMY CHEN, NURSE PRACTITIONER's NPI is 1255792875 with credentials NURSE PRACTITIONER. 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