NPI registry status
Active
2026 NPPES data Allergy & Immunology Physician NPI 1003887738 MD
Verify on CMS → Leon Greos, MD
Allergy & Immunology Physician in Centennial, Colorado.
This profile is drawn from the federal National Provider Identifier Registry (CMS NPPES), which lists more than 7 million U.S. healthcare providers - including 3,390 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
268
Medicare Part D claims · 90 beneficiaries · Allergy & Immunology Physician avg: 764
Generic prescribing
55%
generic claims · 45% 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
Leon Greos, MD filed 268 Medicare Part D claims in 2023 as a Allergy & Immunology Physician in Centennial, Colorado, prescribing 55% generic.
- 268
- Part D claims, 2023
- 55%
- generic prescribing
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.
Leon Greos, MD's Medicare Part D volume vs every U.S. prescriber
Total Medicare Part D claims, 2023, across all CMS prescribers nationally
268 49th percentile higher than 49% 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-eligible specialty (heuristic, not verified)
Leon Greos, MD practices in an ABMS-board-eligible specialty but we don't have enough CMS-participation signals to confirm active board-certified status. Consult CertificationMatters.org (the official ABMS public lookup).
What does the federal data show about Leon Greos, MD?
Quality data not reportedPrimary specialty
Allergy & Immunology Physician
Medicare Part D claims
268 65% vs specialty avg
Specialty distribution in Colorado
How Allergy & Immunology Physician compares to other specialties among Colorado 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).
Leon Greos, MD appears in the CMS NPPES registry as a Allergy & Immunology Physician provider holding MD credentials at 13111 E BRIARWOOD AVE STE 340, Centennial, CO, 80112, with a listed phone of (303) 632-3694. NPI 1003887738 was issued on 01/31/2006.
Medicare Part D records for calendar year 2023 show 268 prescription claims written by this provider, covering 90 Medicare beneficiaries and totaling roughly $87K in drug spend, split 45% brand-name and 55% generic by claim count.
Allergy & Immunology Physician is a narrow specialty nationwide, with 3,390 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 | 1003887738 |
|---|---|
| Specialty | Allergy & Immunology Physician |
| Credentials | MD |
| Gender | Male |
| NPI Issued | 01/31/2006 |
Brand vs generic prescribing mix · Above average
Leon Greos, MD - brand share 45.0%
Allergy & Immunology Physician average
45% brand-name claims vs 55% generic, on 268 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.
268
Total Claims
$87K
Total Drug Cost
90
Medicare Beneficiaries
Prescribing Breakdown
- 30-Day Fills
- 401
- Total Day Supply
- 11,466
- Brand vs Generic
- 45% brand / 55% generic
- Brand Drug Cost
- $83K
- Generic Drug Cost
- $4K
Patient Demographics
- Average Patient Age
- 72.0 years
- Avg HCC Risk Score
- 0.95
- Gender Split
- 63% female / 37% male
Top Prescribed Drugs (Medicare Part D)
Top drugs by claim count for calendar year 2023. Based on Medicare Part D data only.
What Leon Greos, MD prescribes most
Top Medicare Part D drugs by claim count, 2023
- Montelukast Sodium
Montelukast Sodium
45 claims
- Azelastine Hcl
Azelastine Hcl
33 claims
- Advair Diskus
Advair Diskus
24 claims
- Ipratropium Bromide
Ipratropium Bromide
20 claims
- Albuterol Sulfate …
Albuterol Sulfate Hfa
18 claims
- Levalbuterol Tartr… 13
Levalbuterol Tartrate Hfa
13 claims
- Fluticasone Propio… 12
Fluticasone Propionate
12 claims
- Omeprazole 11
Omeprazole
11 claims
| Drug | Claims |
|---|---|
| Montelukast Sodium | 45 |
| Azelastine Hcl | 33 |
| Advair Diskus Fluticasone Propion/Salmeterol | 24 |
| Ipratropium Bromide | 20 |
| Albuterol Sulfate Hfa Albuterol Sulfate | 18 |
| Levalbuterol Tartrate Hfa Levalbuterol Tartrate | 13 |
| Fluticasone Propionate | 12 |
| Omeprazole | 11 |
| Symbicort Budesonide/Formoterol Fumarate | 11 |
* 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 Leon Greos, MD fits within the Allergy & Immunology Physician landscape nationally.
3,390
Allergy & Immunology Physician Providers in US
52
States with Allergy & Immunology Physician
764
Avg Claims per Provider
Leon Greos, MD's 268 claims are below the specialty average of 764.
Nearby Allergy & Immunology Physician Providers in Colorado
Other clinicians with the same primary specialty enrolled in Colorado, drawn from the same CMS NPPES roster as Greos.
Dr. Rafeul Alam
MD
Denver, CO
Dr. Erik Anderson
PHD, DO
Fort Collins, CO
Dr. Francine Andrews
M. D.
Lakewood, CO
Dr. Jatinder Aulakh
MD
Lafayette, CO
Dr. Sanford Avner
M.D.
Lone Tree, CO
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 Colorado 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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Frequently Asked Questions
What is Leon Greos, MD's specialty? ▼
Leon Greos, MD specializes in Allergy & Immunology Physician and practices in Centennial, Colorado. Credentials: MD.
How much does Leon Greos, MD prescribe under Medicare Part D? ▼
In 2023, Leon Greos, MD wrote 268 Medicare Part D claims totaling $87K in drug costs for 90 beneficiaries.
Where is Leon Greos, MD located? ▼
Leon Greos, MD is located at 13111 E BRIARWOOD AVE STE 340, Centennial, CO, 80112. Phone: (303) 632-3694.
What is Leon Greos, MD's NPI number? ▼
Leon Greos, MD's National Provider Identifier (NPI) is 1003887738, issued on 01/31/2006.
Does Leon Greos, MD prescribe more brand-name or generic drugs? ▼
Leon Greos, MD's prescribing is 45% brand-name and 55% generic drugs by claim count, with $83K in brand drug costs.
How many Allergy & Immunology Physician providers are there in the US? ▼
There are 3,390 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 Leon Greos, MD prescribe most often? ▼
Based on 2023 Medicare Part D data, Leon Greos, MD's most frequently prescribed drugs include Montelukast Sodium, Azelastine Hcl, Advair Diskus. This reflects Medicare Part D prescriptions only and does not include commercial insurance or other payer types.
Does Leon Greos, MD accept Medicare? ▼
Leon Greos, MD appears in CMS Medicare data with 268 Part D claims and 90 Medicare beneficiaries in 2023. Contact the provider's office directly to confirm current Medicare enrollment and accepted plans.
How can I verify Leon Greos, MD's credentials? ▼
Leon Greos, MD's NPI is 1003887738 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.
- 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.