NPI registry status
Active
2026 NPPES data Allergy & Immunology Physician NPI 1629031752 M.D.
Verify on CMS → William Anderson, M.D.
Allergy & Immunology Physician in Bellingham, Washington.
This profile is drawn from the federal National Provider Identifier Registry (CMS NPPES), which lists more than 7 million U.S. healthcare providers - including 3,394 in Allergy & Immunology Physician, and covers specialty classification, practice address, and Medicare Part D prescribing data when reported. According to CMS, every field reflects the provider's official federal registration, see our methodology.
Federal data, no proprietary rating.
We show these CMS records as-is - no composite score, no star rating, no editorial opinion layered on top.
Prescribing volume
812
Medicare Part D claims · 136 beneficiaries · Allergy & Immunology Physician avg: 764
Generic prescribing
59%
generic claims · 41% brand-name · higher generic rates reduce patient out-of-pocket costs
Source: CMS Medicare Part D Prescriber Public Use File, 2023
Compiled from official public sources by the PlainDoctor editorial team.
What the federal data shows
William Anderson, M.D. filed 812 Medicare Part D claims in 2023 as a Allergy & Immunology Physician in Bellingham, Washington, prescribing 59% generic.
- 812
- Part D claims, 2023
- 59%
- 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.
William Anderson, M.D.'s Medicare Part D volume vs every U.S. prescriber
Total Medicare Part D claims, 2023, across all CMS prescribers nationally
812 Top 27% higher than 73% of 1,370,886 prescribers
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)
William Anderson, M.D. 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 William Anderson, M.D.?
Quality data not reportedPrimary specialty
Allergy & Immunology Physician
Medicare Part D claims
812 6% vs specialty avg
Specialty distribution in Washington
How Allergy & Immunology Physician compares to other specialties among Washington providers
Board certification
Not published by CMS
CMS does not publish a per-provider board-certification field in NPPES. PlainDoctor does not have a reliable per-specialty certification rate to show for Allergy & Immunology Physician. Verify directly:
How MIPS and board certification work
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).
William Anderson, M.D. appears in the CMS NPPES registry as an Allergy & Immunology Physician provider holding M.D. credentials at 3130 ELLIS ST, Bellingham, WA, 98225, with a listed phone of (425) 339-5412. NPI 1629031752 was issued on 04/10/2006.
Medicare Part D records for calendar year 2023 show 812 prescription claims written by this provider, covering 136 Medicare beneficiaries and totaling roughly $189K in drug spend, split 41% brand-name and 59% generic by claim count.
Allergy & Immunology Physician is a narrow specialty nationwide, with 3,394 enrolled providers across 52 states and an average of 764 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
Provider Details
| NPI | 1629031752 |
|---|---|
| Specialty | Allergy & Immunology Physician |
| Credentials | M.D. |
| Gender | Male |
| NPI Issued | 04/10/2006 |
Hospital and facility affiliations
Facilities where William Anderson, M.D. 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.
Optum Care Washington PLLC
Bellingham, WA
Affiliations sourced from CMS Doctors and Clinicians National Downloadable File; hospital ratings from CMS Hospital General Information dataset (cross-referenced by facility name + state).
License & disciplinary context - Washington WMC 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 ~34K Washington medical licensees in 2023 - they are NOT specific to William Anderson, M.D.. To verify William Anderson, M.D.'s current license status, search the WMC public license lookup directly, or check the Federation of State Medical Boards (FSMB) verification service.
88
Total board actions, Washington 2023
Across 85 cases
2.59
Actions per 1,000 licensees
Washington statewide rate
probation
Most common action type
31 cases
WMC 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 Washington disciplinary trends page. Cross-checked against FSMB U.S. Medical Regulatory Trends.
Brand vs generic prescribing mix · Above average
William Anderson, M.D. - brand share 41.0%
Allergy & Immunology Physician average
41% brand-name claims vs 59% generic, on 812 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.
812
Total Claims
$189K
Total Drug Cost
136
Medicare Beneficiaries
Prescribing Breakdown
- 30-Day Fills
- 1,166
- Total Day Supply
- 32,076
- Brand vs Generic
- 41% brand / 59% generic
- Brand Drug Cost
- $177K
- Generic Drug Cost
- $13K
- Antibiotic Claims
- 38
Patient Demographics
- Average Patient Age
- 70.2 years
- Avg HCC Risk Score
- 1.05
- Gender Split
- 54% female / 46% male
Top Prescribed Drugs (Medicare Part D)
Top drugs by claim count for calendar year 2023. Based on Medicare Part D data only.
What William Anderson, M.D. prescribes most
Top Medicare Part D drugs by claim count, 2023
- Montelukast Sodium
Montelukast Sodium
123 claims
- Fluticasone Propio…
Fluticasone Propionate
76 claims
- Advair Hfa
Advair Hfa
67 claims
- Albuterol Sulfate …
Albuterol Sulfate Hfa
65 claims
- Fluticasone-Salmet…
Fluticasone-Salmeterol
65 claims
- Prednisone
Prednisone
52 claims
- Symbicort 39
Symbicort
39 claims
- Azelastine Hcl 38
Azelastine Hcl
38 claims
| Drug | Claims |
|---|---|
| Montelukast Sodium | 123 |
| Fluticasone Propionate | 76 |
| Advair Hfa Fluticasone Propion/Salmeterol | 67 |
| Albuterol Sulfate Hfa Albuterol Sulfate | 65 |
| Fluticasone-Salmeterol Fluticasone Propion/Salmeterol | 65 |
| Prednisone | 52 |
| Symbicort Budesonide/Formoterol Fumarate | 39 |
| Azelastine Hcl | 38 |
| Advair Diskus Fluticasone Propion/Salmeterol | 30 |
| Ipratropium Bromide | 30 |
* Counts below 11 are suppressed by CMS for patient privacy. Generic names shown where available from CMS Part D data.
Allergy & Immunology Physician Overview
How William Anderson, M.D. fits within the Allergy & Immunology Physician landscape nationally.
3,394
Allergy & Immunology Physician Providers in US
52
States with Allergy & Immunology Physician
764
Avg Claims per Provider
William Anderson, M.D.'s 812 claims are above the specialty average of 764.
Nearby Allergy & Immunology Physician Providers in Washington
Other clinicians with the same primary specialty enrolled in Washington, drawn from the same CMS NPPES roster as Anderson.
Dr. Vivek Agarwal
M.D.
Silverdale, WA
Dr. George Allen
MD
Vancouver, WA
Dr. Leonard Altman
M.D.
Seattle, WA
Dr. W Andrade
MD
Lakewood, WA
Dr. Nola Attaway
M.D.
Yakima, WA
Compare Allergy & Immunology Physician nationally: see state-by-state distribution →
Before you book an appointment
Use this federal record as your verification checklist, not as a recommendation.
- Confirm the NPI record is current in the official CMS registry, providers update their own NPPES details, and moves can lag. Verify this NPI
- Check the active license and any disciplinary history with the Washington medical board, federal registration is not a license check. Credential verification guide
- Weigh a second option: compare this provider with a nearby Allergy & Immunology Physician peer on Medicare volume and prescribing patterns. Compare providers
Medicare Part D and MIPS figures describe practice patterns in federal programs only, they are not quality ratings, and PlainDoctor does not rate, rank, or recommend providers.
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Medical Specialties Explained
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Frequently Asked Questions
What is William Anderson, M.D.'s specialty? ▼
William Anderson, M.D. specializes in Allergy & Immunology Physician and practices in Bellingham, Washington. Credentials: M.D..
How much does William Anderson, M.D. prescribe under Medicare Part D? ▼
In 2023, William Anderson, M.D. wrote 812 Medicare Part D claims totaling $189K in drug costs for 136 beneficiaries.
Where is William Anderson, M.D. located? ▼
William Anderson, M.D. is located at 3130 ELLIS ST, Bellingham, WA, 98225. Phone: (425) 339-5412.
What is William Anderson, M.D.'s NPI number? ▼
William Anderson, M.D.'s National Provider Identifier (NPI) is 1629031752, issued on 04/10/2006.
Does William Anderson, M.D. prescribe more brand-name or generic drugs? ▼
William Anderson, M.D.'s prescribing is 41% brand-name and 59% generic drugs by claim count, with $177K in brand drug costs.
How many Allergy & Immunology Physician providers are there in the US? ▼
There are 3,394 Allergy & Immunology Physician providers across 52 states in the US. The average Allergy & Immunology Physician provider writes 764 Medicare Part D claims per year.
What drugs does William Anderson, M.D. prescribe most often? ▼
Based on 2023 Medicare Part D data, William Anderson, M.D.'s most frequently prescribed drugs include Montelukast Sodium, Fluticasone Propionate, Advair Hfa. This reflects Medicare Part D prescriptions only and does not include commercial insurance or other payer types.
Does William Anderson, M.D. accept Medicare? ▼
William Anderson, M.D. appears in CMS Medicare data with 812 Part D claims and 136 Medicare beneficiaries in 2023. Contact the provider's office directly to confirm current Medicare enrollment and accepted plans.
How can I verify William Anderson, M.D.'s credentials? ▼
William Anderson, M.D.'s NPI is 1629031752 with credentials M.D.. 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
View source datasets and methodology notes
- 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
Compiled from official public sources by the PlainDoctor editorial team.
Every figure on PlainDoctor is rendered directly from the federal CMS NPPES registry, Medicare Part D, MIPS, and Open Payments records, no number is typed in by an editor. See our editorial standards & corrections policy, the methodology behind these numbers, or report a data error. Data current as of May 2026.