2026 NPPES data Critical Care Medicine Nurse Practitioner NPI 1477792604 NP
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IRENE IRBY, NP

Critical Care Medicine Nurse Practitioner in ANNAPOLIS, Maryland. 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
2K
Medicare Part D claims · 271 beneficiaries · Critical Care Medicine Nurse Practitioner avg: 426
Generic prescribing
44%
generic claims · 56% brand-name · higher generic rates reduce patient out-of-pocket costs

What the federal data shows

IRENE IRBY, NP filed 1,558 Medicare Part D claims in 2023 as a Critical Care Medicine Nurse Practitioner in ANNAPOLIS, Maryland, prescribing 44% generic.

2K
Part D claims, 2023
44%
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.

IRENE IRBY, NP's Medicare Part D volume vs every U.S. prescriber

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

1,558 Top 19% higher than 81% of 1,370,886 prescribers

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

Quality data not reported

NPI registry status

Active

Issued 02/11/2009

NPI 1477792604

Primary specialty

Critical Care Medicine Nurse Practitioner

Niche

1,410 US NPIs in this specialty

Medicare Part D claims

1,558 266% vs specialty avg

2023 prescription claims

Specialty avg: 426

Specialty distribution in Maryland

How Critical Care Medicine Nurse Practitioner compares to other specialties among Maryland providers

Maryland providers

Critical Care Medicine Nurse Practitioner share within Maryland

1. Critical Care Medicine Nurse Practitioner42%2. Internal medicine21%3. Family medicine17%4. Surgical12%5. Pediatric8%
Critical Care Medicine Nurse Practitioner share within Maryland

Specialty board-certification context

Estimated specialty board-certified rate — Critical Care Medicine Nurse Practitioner (ABMS / AOA reference)

Quality data not reported
Est. board-certified rate
78%
Critical Care Medicine Nurse Practitioner ABMS/AOA estimate

Est. board-certified rate (Critical Care Medicine Nurse Practitioner) — ABMS / AOA estimate

0%100%78%
Est. board-certified rate (Critical Care Medicine Nurse Practitioner) — 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).

IRENE IRBY, NP appears in the CMS NPPES registry as a Critical Care Medicine Nurse Practitioner provider holding NP credentials at 108 FORBES ST, ANNAPOLIS, MD, 21401, with a listed phone of (410) 571-7880. NPI 1477792604 was issued on 02/11/2009. Because NPPES data is self-reported by the provider and refreshed monthly, the address, phone, and specialty reflect what IRBY 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 1,558 prescription claims written by this provider, covering 271 Medicare beneficiaries and totaling roughly $1.1 million in drug spend, split 56% brand-name and 44% 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.

Critical Care Medicine Nurse Practitioner is a narrow specialty nationwide, with 1,410 enrolled providers across 50 states and an average of 426 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

108 FORBES ST
ANNAPOLIS, MD 21401

Provider Details

NPI 1477792604
Specialty Critical Care Medicine Nurse Practitioner
Credentials NP
Gender Female
NPI Issued 02/11/2009

Brand vs generic prescribing mix · Brand-heavy

IRENE IRBY, NP — brand share 56.0%
Specialty average (est.)

56% brand-name claims vs 44% generic, on 1,558 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.

1,558
Total Claims
$1.1M
Total Drug Cost
271
Medicare Beneficiaries

Prescribing Breakdown

30-Day Fills
3,378
Total Day Supply
99,962
Brand vs Generic
56% brand / 44% generic
Brand Drug Cost
$1.0M
Generic Drug Cost
$13K

Patient Demographics

Average Patient Age
69.8 years
Avg HCC Risk Score
1.61
Gender Split
70% female / 30% male
Age Distribution
<65: 46, 65-74: 144, 75-84: 70, 85+: 11

Top Prescribed Drugs (Medicare Part D)

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

What IRENE IRBY, NP prescribes most

Top Medicare Part D drugs by claim count, 2023

claims
Source CMS Medicare Part D Prescriber Public Use File As of 2023
Drug Claims
Levothyroxine Sodium
240
Mounjaro
Tirzepatide
143
Ozempic
Semaglutide
92
Trulicity
Dulaglutide
87
Metformin Hcl
76
Jardiance
Empagliflozin
57
Rosuvastatin Calcium
31
Synthroid
Levothyroxine Sodium
30
Novolog Flexpen
Insulin Aspart
29
Atorvastatin Calcium
27

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

Critical Care Medicine Nurse Practitioner Overview

How IRENE IRBY, NP fits within the Critical Care Medicine Nurse Practitioner landscape nationally.

1,410
Critical Care Medicine Nurse Practitioner Providers in US
50
States with Critical Care Medicine Nurse Practitioner
426
Avg Claims per Provider

IRENE IRBY, NP's 1,558 claims are above the specialty average of 426.

Nearby Critical Care Medicine Nurse Practitioner Providers in Maryland

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

Compare Critical Care Medicine Nurse Practitioner nationally: see state-by-state distribution →

Frequently Asked Questions

What is IRENE IRBY, NP's specialty?
IRENE IRBY, NP specializes in Critical Care Medicine Nurse Practitioner and practices in ANNAPOLIS, Maryland. Credentials: NP.
How much does IRENE IRBY, NP prescribe under Medicare Part D?
In 2023, IRENE IRBY, NP wrote 1,558 Medicare Part D claims totaling $1.1M in drug costs for 271 beneficiaries.
Where is IRENE IRBY, NP located?
IRENE IRBY, NP is located at 108 FORBES ST, ANNAPOLIS, MD, 21401. Phone: (410) 571-7880.
What is IRENE IRBY, NP's NPI number?
IRENE IRBY, NP's National Provider Identifier (NPI) is 1477792604, issued on 02/11/2009.
Does IRENE IRBY, NP prescribe more brand-name or generic drugs?
IRENE IRBY, NP's prescribing is 56% brand-name and 44% generic drugs by claim count, with $1.0M in brand drug costs.
How many Critical Care Medicine Nurse Practitioner providers are there in the US?
There are 1,410 Critical Care Medicine Nurse Practitioner providers across 50 states in the US. The average Critical Care Medicine Nurse Practitioner provider writes 426 Medicare Part D claims per year.
What drugs does IRENE IRBY, NP prescribe most often?
Based on 2023 Medicare Part D data, IRENE IRBY, NP's most frequently prescribed drugs include Levothyroxine Sodium, Mounjaro, Ozempic. This reflects Medicare Part D prescriptions only and does not include commercial insurance or other payer types.
Does IRENE IRBY, NP accept Medicare?
IRENE IRBY, NP appears in CMS Medicare data with 1,558 Part D claims and 271 Medicare beneficiaries in 2023. Contact the provider's office directly to confirm current Medicare enrollment and accepted plans.
How can I verify IRENE IRBY, NP's credentials?
IRENE IRBY, NP's NPI is 1477792604 with credentials NP. 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