NPI registry status
Active
2026 NPPES data Medical Toxicology (Emergency Medicine) Physician NPI 1235591439
Verify on CMS → Grant Comstock
Medical Toxicology (Emergency Medicine) Physician in Milwaukee, Wisconsin.
This profile is drawn from the federal National Provider Identifier Registry (CMS NPPES), which lists more than 7 million U.S. healthcare providers - including 228 in Medical Toxicology (Emergency 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
183
Medicare Part D claims · 140 beneficiaries · Medical Toxicology (Emergency Medicine) Physician avg: 329
Generic prescribing
93%
generic claims · 7% 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
Grant Comstock filed 183 Medicare Part D claims in 2023 as a Medical Toxicology (Emergency Medicine) Physician in Milwaukee, Wisconsin, prescribing 93% generic.
- 183
- Part D claims, 2023
- 93%
- 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.
Grant Comstock's Medicare Part D volume vs every U.S. prescriber
Total Medicare Part D claims, 2023, across all CMS prescribers nationally
183 35th percentile higher than 35% 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)
Grant Comstock 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 Grant Comstock?
Quality data not reportedPrimary specialty
Medical Toxicology (Emergency Medicine) Physician
Medicare Part D claims
183 44% vs specialty avg
Specialty distribution in Wisconsin
How Medical Toxicology (Emergency Medicine) Physician compares to other specialties among Wisconsin 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 Medical Toxicology (Emergency Medicine) 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).
Grant Comstock appears in the CMS NPPES registry as a Medical Toxicology (Emergency Medicine) Physician provider at 9200 W WISCONSIN AVE, Milwaukee, WI, 53226, with a listed phone of (414) 955-6450. NPI 1235591439 was issued on 03/25/2016.
Medicare Part D records for calendar year 2023 show 183 prescription claims written by this provider, covering 140 Medicare beneficiaries and totaling roughly $10K in drug spend, split 7% brand-name and 93% generic by claim count, with an opioid prescribing rate of 6.6%.
Medical Toxicology (Emergency Medicine) Physician is a narrow specialty nationwide, with 228 enrolled providers across 39 states and an average of 329 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 | 1235591439 |
|---|---|
| Specialty | Medical Toxicology (Emergency Medicine) Physician |
| Gender | Male |
| NPI Issued | 03/25/2016 |
Hospital and facility affiliations
Facilities where Grant Comstock 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.
The Medical College OF Wisconsin Inc
Milwaukee, WI
Affiliations sourced from CMS Doctors and Clinicians National Downloadable File; hospital ratings from CMS Hospital General Information dataset (cross-referenced by facility name + state).
Brand vs generic prescribing mix · Generic-heavy
Grant Comstock - brand share 7.0%
Medical Toxicology (Emergency Medicine) Physician average
7% brand-name claims vs 93% generic, on 183 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.
183
Total Claims
$10K
Total Drug Cost
140
Medicare Beneficiaries
Prescribing Breakdown
- 30-Day Fills
- 187
- Total Day Supply
- 1,912
- Brand vs Generic
- 7% brand / 93% generic
- Brand Drug Cost
- $8K
- Generic Drug Cost
- $2K
- Opioid Claims
- 12 (6.6% rate)
- Antibiotic Claims
- 71
Patient Demographics
- Average Patient Age
- 71.3 years
- Avg HCC Risk Score
- 2.26
- Gender Split
- 56% female / 44% male
- Age Distribution
- <65: 23, 65-74: 57, 75-84: 48, 85+: 12
Top Prescribed Drugs (Medicare Part D)
Top drugs by claim count for calendar year 2023. Based on Medicare Part D data only.
What Grant Comstock prescribes most
Top Medicare Part D drugs by claim count, 2023
- Cefdinir
Cefdinir
19 claims
- Cephalexin
Cephalexin
16 claims
- Prednisone
Prednisone
14 claims
- Ondansetron Odt
Ondansetron Odt
13 claims
- Oxycodone Hcl
Oxycodone Hcl
12 claims
- Doxycycline Hyclate
Doxycycline Hyclate
11 claims
| Drug | Claims |
|---|---|
| Cefdinir | 19 |
| Cephalexin | 16 |
| Prednisone | 14 |
| Ondansetron Odt Ondansetron | 13 |
| Oxycodone Hcl | 12 |
| Doxycycline Hyclate | 11 |
* Counts below 11 are suppressed by CMS for patient privacy. Generic names shown where available from CMS Part D data.
More Medical Toxicology (Emergency Medicine) Physician in WI →
All providers in Wisconsin →
Compare specialties →
Medical Toxicology (Emergency Medicine) Physician Overview
How Grant Comstock fits within the Medical Toxicology (Emergency Medicine) Physician landscape nationally.
228
Medical Toxicology (Emergency Medicine) Physician Providers in US
39
States with Medical Toxicology (Emergency Medicine) Physician
329
Avg Claims per Provider
Grant Comstock's 183 claims are below the specialty average of 329.
Nearby Medical Toxicology (Emergency Medicine) Physician Providers in Wisconsin
Other clinicians with the same primary specialty enrolled in Wisconsin, drawn from the same CMS NPPES roster as Comstock.
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 Wisconsin medical board, federal registration is not a license check. Credential verification guide
- Weigh a second option: compare this provider with a nearby Medical Toxicology (Emergency 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.
Healthcare Guides
Learn more about finding, verifying, and understanding healthcare providers.
How to Find a Doctor
Step-by-step guide to choosing a provider
Verify Credentials
Check NPI, board certification & license status
Medical Specialties Explained
Who treats what and how specialties differ
Understanding Medicare Claims Data
What prescribing data reveals about a provider
In-Network vs Out-of-Network
How insurance networks affect your costs
Telehealth Guide
Virtual care options and coverage in 2026
Explore Wisconsin
Frequently Asked Questions
What is Grant Comstock's specialty? ▼
Grant Comstock specializes in Medical Toxicology (Emergency Medicine) Physician and practices in Milwaukee, Wisconsin.
How much does Grant Comstock prescribe under Medicare Part D? ▼
In 2023, Grant Comstock wrote 183 Medicare Part D claims totaling $10K in drug costs for 140 beneficiaries.
Where is Grant Comstock located? ▼
Grant Comstock is located at 9200 W WISCONSIN AVE, Milwaukee, WI, 53226. Phone: (414) 955-6450.
What is Grant Comstock's NPI number? ▼
Grant Comstock's National Provider Identifier (NPI) is 1235591439, issued on 03/25/2016.
Does Grant Comstock prescribe more brand-name or generic drugs? ▼
Grant Comstock's prescribing is 7% brand-name and 93% generic drugs by claim count, with $8K in brand drug costs.
Does Grant Comstock prescribe opioids? ▼
Yes, Grant Comstock had 12 opioid claims in 2023 with an opioid prescribing rate of 6.6%.
How many Medical Toxicology (Emergency Medicine) Physician providers are there in the US? ▼
There are 228 Medical Toxicology (Emergency Medicine) Physician providers across 39 states in the US. The average Medical Toxicology (Emergency Medicine) Physician provider writes 329 Medicare Part D claims per year.
What drugs does Grant Comstock prescribe most often? ▼
Based on 2023 Medicare Part D data, Grant Comstock's most frequently prescribed drugs include Cefdinir, Cephalexin, Prednisone. This reflects Medicare Part D prescriptions only and does not include commercial insurance or other payer types.
Does Grant Comstock accept Medicare? ▼
Grant Comstock appears in CMS Medicare data with 183 Part D claims and 140 Medicare beneficiaries in 2023. Contact the provider's office directly to confirm current Medicare enrollment and accepted plans.
How can I verify Grant Comstock's credentials? ▼
Grant Comstock's NPI is 1235591439. 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.