NPI registry status
Active
2026 NPPES data Allergy & Immunology (Internal Medicine) Physician NPI 1811056567 MD
Verify on CMS → William Calhoun, MD
Allergy & Immunology (Internal Medicine) Physician in Galveston, Texas.
This profile is drawn from the federal National Provider Identifier Registry (CMS NPPES), which lists more than 7 million U.S. healthcare providers - including 517 in Allergy & Immunology (Internal Medicine) 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
328
Medicare Part D claims · 48 beneficiaries · Allergy & Immunology (Internal Medicine) Physician avg: 798
Generic prescribing
28%
generic claims · 72% brand-name · higher generic rates reduce patient out-of-pocket costs
MIPS score
75/100
▼ 8 pts below national avg 83.1 · Mid-tier
Industry payments
$137.8K
71 payments · CMS Open Payments (Sunshine Act)
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 Calhoun, MD reported a CMS MIPS final score of 75/100 - below the 83.1 national average - and filed 328 Medicare Part D claims in 2023.
- 75/100
- MIPS score · -8 vs avg
- 328
- Part D claims, 2023
- 28%
- 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 Calhoun, MD's MIPS score vs every scored U.S. clinician
CMS Merit-based Incentive Payment System (MIPS) final score, 2023, the federal quality measure
75 12th percentile higher than 12% of 477,587 scored providers
Each bar is a band; taller bars hold more scored providers. 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 Merit-based Incentive Payment System (MIPS) · 2023
Where William Calhoun, MD sits
This provider among allergy & immunology (internal medicine) physician peers
Across the 130 allergy & immunology (internal medicine) physician providers who report both Medicare Part D prescribing and a MIPS quality score, William Calhoun, MD writes more Part D claims than 45% of them and scores higher on MIPS quality than 17% - placing this provider in the lower-volume, lower-quality quadrant. Volume reflects patient-panel size and specialty, not quality; the two axes are independent.
Part D claim volume vs MIPS quality, by specialty percentile
Each dot is one allergy & immunology (internal medicine) physician peer from a representative sample of 60; the gold marker is William Calhoun, MD. Source: CMS Medicare Part D Prescriber data and the CMS Merit-based Incentive Payment System, 2023.
✓
Board certification likely (heuristic, not verified)
William Calhoun, MD practices in an ABMS-board-eligible specialty and shows active CMS Medicare participation + MIPS quality reporting + 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 Calhoun, MD?
Below national averagePrimary specialty
Allergy & Immunology (Internal Medicine) Physician
Medicare Part D claims
328 59% vs specialty avg
MIPS final score
75/100 8.1 pts vs avg
Specialty distribution in Texas
How Allergy & Immunology (Internal Medicine) Physician compares to other specialties among Texas providers
Medicare quality performance, MIPS
William Calhoun, MD's 2023 MIPS final score plotted against the Allergy & Immunology (Internal Medicine) Physician national average
- MIPS Final Score
- 75/100
- vs 83.1 national avg · 2023 performance year
MIPS final score (Allergy & Immunology (Internal Medicine) Physician) - 75/100 vs national avg 83.1
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 Calhoun, MD appears in the CMS NPPES registry as an Allergy & Immunology (Internal Medicine) Physician provider holding MD credentials at 301 UNIVERSITY BLVD, Galveston, TX, 77555, with a listed phone of (409) 772-2222. NPI 1811056567 was issued on 12/08/2006.
Medicare Part D records for calendar year 2023 show 328 prescription claims written by this provider, covering 48 Medicare beneficiaries and totaling roughly $230K in drug spend, split 72% brand-name and 28% generic by claim count. On the CMS Merit-based Incentive Payment System, this provider earned a Final Score of 75/100 for the 2023 performance year (Quality 73.8, Cost 47.8), compared with the national average of 83.1.
Allergy & Immunology (Internal Medicine) Physician is a narrow specialty nationwide, with 517 enrolled providers across 47 states and an average of 798 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 | 1811056567 |
|---|---|
| Specialty | Allergy & Immunology (Internal Medicine) Physician |
| Credentials | MD |
| Gender | Male |
| NPI Issued | 12/08/2006 |
CMS Quality Score (MIPS)
Merit-based Incentive Payment System (MIPS) scores from CMS, 2023 performance year.
74.9614
Final Score
Avg: 83.1
73.7789
Quality
47.7591
Cost
94
Promoting Interoperability
Reporting: Group practice
Hospital and facility affiliations
Facilities where William Calhoun, MD 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.
Utmb Faculty Group Practice
League City, TX
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 William Calhoun, MD. Source: openpaymentsdata.cms.gov.
Total received
$137.8K
Largest payer
GENZYME CORPORATION
Most common payment type
Travel and Lodging
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 - Texas TMB 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 ~77K Texas medical licensees in 2023 - they are NOT specific to William Calhoun, MD. To verify William Calhoun, MD's current license status, search the TMB public license lookup directly, or check the Federation of State Medical Boards (FSMB) verification service.
344
Total board actions, Texas 2023
Across 334 cases
4.47
Actions per 1,000 licensees
Texas statewide rate
probation
Most common action type
94 cases
TMB 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 Texas disciplinary trends page. Cross-checked against FSMB U.S. Medical Regulatory Trends.
Brand vs generic prescribing mix · Brand-heavy
William Calhoun, MD - brand share 72.0%
Allergy & Immunology (Internal Medicine) Physician average
72% brand-name claims vs 28% generic, on 328 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.
328
Total Claims
$230K
Total Drug Cost
48
Medicare Beneficiaries
Prescribing Breakdown
- 30-Day Fills
- 437
- Total Day Supply
- 12,563
- Brand vs Generic
- 72% brand / 28% generic
- Brand Drug Cost
- $228K
- Generic Drug Cost
- $2K
Patient Demographics
- Average Patient Age
- 71.1 years
- Avg HCC Risk Score
- 1.88
- Gender Split
- 63% female / 38% 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 Calhoun, MD prescribes most
Top Medicare Part D drugs by claim count, 2023
- Symbicort
Symbicort
50 claims
- Albuterol Sulfate …
Albuterol Sulfate Hfa
44 claims
- Trelegy Ellipta
Trelegy Ellipta
44 claims
- Fluticasone Propio…
Fluticasone Propionate
28 claims
- Anoro Ellipta
Anoro Ellipta
22 claims
- Dupixent Pen
Dupixent Pen
22 claims
- Montelukast Sodium
Montelukast Sodium
20 claims
- Incruse Ellipta 19
Incruse Ellipta
19 claims
| Drug | Claims |
|---|---|
| Symbicort Budesonide/Formoterol Fumarate | 50 |
| Albuterol Sulfate Hfa Albuterol Sulfate | 44 |
| Trelegy Ellipta Fluticasone/Umeclidin/Vilanter | 44 |
| Fluticasone Propionate | 28 |
| Anoro Ellipta Umeclidinium Brm/Vilanterol Tr | 22 |
| Dupixent Pen Dupilumab | 22 |
| Montelukast Sodium | 20 |
| Incruse Ellipta Umeclidinium Bromide | 19 |
| Stiolto Respimat Tiotropium Br/Olodaterol Hcl | 11 |
* Counts below 11 are suppressed by CMS for patient privacy. Generic names shown where available from CMS Part D data.
More Allergy & Immunology (Internal Medicine) Physician in TX →
All providers in Texas →
Compare specialties →
Allergy & Immunology (Internal Medicine) Physician Overview
How William Calhoun, MD fits within the Allergy & Immunology (Internal Medicine) Physician landscape nationally.
517
Allergy & Immunology (Internal Medicine) Physician Providers in US
47
States with Allergy & Immunology (Internal Medicine) Physician
798
Avg Claims per Provider
William Calhoun, MD's 328 claims are below the specialty average of 798.
Nearby Allergy & Immunology (Internal Medicine) Physician Providers in Texas
Other clinicians with the same primary specialty enrolled in Texas, drawn from the same CMS NPPES roster as Calhoun.
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 Texas medical board, federal registration is not a license check. Credential verification guide
- Weigh a second option: compare this provider with a nearby Allergy & Immunology (Internal Medicine) 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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Frequently Asked Questions
What is William Calhoun, MD's specialty? ▼
William Calhoun, MD specializes in Allergy & Immunology (Internal Medicine) Physician and practices in Galveston, Texas. Credentials: MD.
How much does William Calhoun, MD prescribe under Medicare Part D? ▼
In 2023, William Calhoun, MD wrote 328 Medicare Part D claims totaling $230K in drug costs for 48 beneficiaries.
What is William Calhoun, MD's Medicare quality score? ▼
William Calhoun, MD has a CMS MIPS Final Score of 75/100 (Quality: 73.8, Cost: 47.8). The national average MIPS Final Score is 83.1. Source: CMS Merit-based Incentive Payment System (MIPS) 2023.
Where is William Calhoun, MD located? ▼
William Calhoun, MD is located at 301 UNIVERSITY BLVD, Galveston, TX, 77555. Phone: (409) 772-2222.
What is William Calhoun, MD's NPI number? ▼
William Calhoun, MD's National Provider Identifier (NPI) is 1811056567, issued on 12/08/2006.
Does William Calhoun, MD prescribe more brand-name or generic drugs? ▼
William Calhoun, MD's prescribing is 72% brand-name and 28% generic drugs by claim count, with $228K in brand drug costs.
How many Allergy & Immunology (Internal Medicine) Physician providers are there in the US? ▼
There are 517 Allergy & Immunology (Internal Medicine) Physician providers across 47 states in the US. The average Allergy & Immunology (Internal Medicine) Physician provider writes 798 Medicare Part D claims per year.
What drugs does William Calhoun, MD prescribe most often? ▼
Based on 2023 Medicare Part D data, William Calhoun, MD's most frequently prescribed drugs include Symbicort, Albuterol Sulfate Hfa, Trelegy Ellipta. This reflects Medicare Part D prescriptions only and does not include commercial insurance or other payer types.
Does William Calhoun, MD accept Medicare? ▼
William Calhoun, MD appears in CMS Medicare data with 328 Part D claims and 48 Medicare beneficiaries in 2023. Contact the provider's office directly to confirm current Medicare enrollment and accepted plans.
How can I verify William Calhoun, MD's credentials? ▼
William Calhoun, MD's NPI is 1811056567 with credentials MD. 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.
- Quality Performance
- CMS Merit-based Incentive Payment System (MIPS) - 2023 performance year.
- 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.