2026 NPPES data Pharmacist NPI 1851012520
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DARWIN CARSTENSEN

Pharmacist in MARION, Iowa. 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
30
Medicare Part D claims · 29 beneficiaries · Pharmacist avg: 135
Generic prescribing
0%
generic claims · 100% brand-name · higher generic rates reduce patient out-of-pocket costs

What the federal data shows

DARWIN CARSTENSEN filed 30 Medicare Part D claims in 2023 as a Pharmacist in MARION, Iowa, prescribing 0% generic.

30
Part D claims, 2023
0%
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.

DARWIN CARSTENSEN's Medicare Part D volume vs every U.S. prescriber

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

30 0th percentile higher than 0% of 1,370,886 prescribers

0–200: 670,926 prescribers (49%). This entry sits in this band. 200–400: 182,923 prescribers (13%). Above this entry. 400–600: 90,619 prescribers (7%). Above this entry. 600–800: 56,224 prescribers (4%). Above this entry. 800–1,000: 40,919 prescribers (3%). Above this entry. 1,000–1,200: 31,827 prescribers (2%). Above this entry. 1,200–1,400: 26,224 prescribers (2%). Above this entry. 1,400–1,600: 21,710 prescribers (2%). Above this entry. 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 DARWIN CARSTENSEN?

Quality data not reported

NPI registry status

Active

Issued 09/09/2022

NPI 1851012520

Primary specialty

Pharmacist

High-volume

290,447 US NPIs in this specialty

Medicare Part D claims

30 78% vs specialty avg

2023 prescription claims

Specialty avg: 135

Specialty distribution in Iowa

How Pharmacist compares to other specialties among Iowa providers

Iowa providers

Pharmacist share within Iowa

1. Pharmacist42%2. Internal medicine21%3. Family medicine17%4. Surgical12%5. Pediatric8%
Pharmacist share within Iowa

Specialty board-certification context

Estimated specialty board-certified rate — Pharmacist (ABMS / AOA reference)

Quality data not reported
Est. board-certified rate
78%
Pharmacist ABMS/AOA estimate

Est. board-certified rate (Pharmacist) — ABMS / AOA estimate

0%100%78%
Est. board-certified rate (Pharmacist) — 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).

DARWIN CARSTENSEN appears in the CMS NPPES registry as a Pharmacist provider at 3492 LENNON LN, MARION, IA, 52302, with a listed phone of (319) 721-6379. NPI 1851012520 was issued on 09/09/2022. Because NPPES data is self-reported by the provider and refreshed monthly, the address, phone, and specialty reflect what CARSTENSEN 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 30 prescription claims written by this provider, covering 29 Medicare beneficiaries and totaling roughly $7K in drug spend, split 100% brand-name and 0% generic by claim count. 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.

Pharmacist is a high-volume specialty nationwide, with 290,447 enrolled providers across 56 states and an average of 135 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

3492 LENNON LN
MARION, IA 52302

Provider Details

NPI 1851012520
Specialty Pharmacist
Gender Male
NPI Issued 09/09/2022

Brand vs generic prescribing mix · Brand-heavy

DARWIN CARSTENSEN — brand share 100.0%
Specialty average (est.)

100% brand-name claims vs 0% generic, on 30 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.

30
Total Claims
$7K
Total Drug Cost
29
Medicare Beneficiaries

Prescribing Breakdown

30-Day Fills
30
Total Day Supply
30
Brand vs Generic
100% brand / 0% generic
Brand Drug Cost
$7K
Generic Drug Cost
$0

Patient Demographics

Average Patient Age
71.3 years
Avg HCC Risk Score
1.16
Gender Split
52% female / 48% male

Top Prescribed Drugs (Medicare Part D)

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

Drug Claims
Shingrix
Varicella-Zoster Ge/As01b/Pf
18

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

Pharmacist Overview

How DARWIN CARSTENSEN fits within the Pharmacist landscape nationally.

290,447
Pharmacist Providers in US
56
States with Pharmacist
135
Avg Claims per Provider

DARWIN CARSTENSEN's 30 claims are below the specialty average of 135.

Nearby Pharmacist Providers in Iowa

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

Compare Pharmacist nationally: see state-by-state distribution →

Frequently Asked Questions

What is DARWIN CARSTENSEN's specialty?
DARWIN CARSTENSEN specializes in Pharmacist and practices in MARION, Iowa.
How much does DARWIN CARSTENSEN prescribe under Medicare Part D?
In 2023, DARWIN CARSTENSEN wrote 30 Medicare Part D claims totaling $7K in drug costs for 29 beneficiaries.
Where is DARWIN CARSTENSEN located?
DARWIN CARSTENSEN is located at 3492 LENNON LN, MARION, IA, 52302. Phone: (319) 721-6379.
What is DARWIN CARSTENSEN's NPI number?
DARWIN CARSTENSEN's National Provider Identifier (NPI) is 1851012520, issued on 09/09/2022.
Does DARWIN CARSTENSEN prescribe more brand-name or generic drugs?
DARWIN CARSTENSEN's prescribing is 100% brand-name and 0% generic drugs by claim count, with $7K in brand drug costs.
How many Pharmacist providers are there in the US?
There are 290,447 Pharmacist providers across 56 states in the US. The average Pharmacist provider writes 135 Medicare Part D claims per year.
What drugs does DARWIN CARSTENSEN prescribe most often?
Based on 2023 Medicare Part D data, DARWIN CARSTENSEN's most frequently prescribed drugs include Shingrix. This reflects Medicare Part D prescriptions only and does not include commercial insurance or other payer types.
Does DARWIN CARSTENSEN accept Medicare?
DARWIN CARSTENSEN appears in CMS Medicare data with 30 Part D claims and 29 Medicare beneficiaries in 2023. Contact the provider's office directly to confirm current Medicare enrollment and accepted plans.
How can I verify DARWIN CARSTENSEN's credentials?
DARWIN CARSTENSEN's NPI is 1851012520. 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