NPI registry status
Active
2026 NPPES data Acute Care Nurse Practitioner NPI 1487694659 FNP
Verify on CMS → Mary Ernst, FNP
Acute Care Nurse Practitioner in Saint Peters, Missouri.
This profile is drawn from the federal National Provider Identifier Registry (CMS NPPES), which lists more than 7 million U.S. healthcare providers - including 24,697 in Acute Care Nurse Practitioner, 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
236
Medicare Part D claims · 157 beneficiaries · Acute Care Nurse Practitioner avg: 576
Compiled from official public sources by the PlainDoctor editorial team.
What the federal data shows
Mary Ernst, FNP filed 236 Medicare Part D claims in 2023 as a Acute Care Nurse Practitioner in Saint Peters, Missouri.
- 236
- Part D claims, 2023
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.
Mary Ernst, FNP's Medicare Part D volume vs every U.S. prescriber
Total Medicare Part D claims, 2023, across all CMS prescribers nationally
236 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
What does the federal data show about Mary Ernst, FNP?
Quality data not reportedPrimary specialty
Acute Care Nurse Practitioner
Medicare Part D claims
236 59% vs specialty avg
Specialty distribution in Missouri
How Acute Care Nurse Practitioner compares to other specialties among Missouri 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 Acute Care Nurse Practitioner. 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).
Mary Ernst, FNP appears in the CMS NPPES registry as an Acute Care Nurse Practitioner provider holding FNP credentials at 107 PIPER HILL DR, Saint Peters, MO, 63376, with a listed phone of (636) 477-8757. NPI 1487694659 was issued on 06/07/2006.
Medicare Part D records for calendar year 2023 show 236 prescription claims written by this provider, covering 157 Medicare beneficiaries and totaling roughly $2K in drug spend.
Acute Care Nurse Practitioner is a mid-sized specialty nationwide, with 24,697 enrolled providers across 53 states and an average of 576 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 | 1487694659 |
|---|---|
| Specialty | Acute Care Nurse Practitioner |
| Credentials | FNP |
| Gender | Female |
| NPI Issued | 06/07/2006 |
Hospital and facility affiliations
Facilities where Mary Ernst, FNP 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.
Physician Groups LC
Saint Louis, MO
Affiliations sourced from CMS Doctors and Clinicians National Downloadable File; hospital ratings from CMS Hospital General Information dataset (cross-referenced by facility name + state).
Medicare Part D Prescribing Data
CMS Medicare Part D prescriber-level data for calendar year 2023.
236
Total Claims
$2K
Total Drug Cost
157
Medicare Beneficiaries
Prescribing Breakdown
- 30-Day Fills
- 246
- Total Day Supply
- 2,382
- Generic Drug Cost
- $2K
- Antibiotic Claims
- 94
Patient Demographics
- Average Patient Age
- 72.0 years
- Avg HCC Risk Score
- 1.22
- Gender Split
- 68% female / 32% male
Top Prescribed Drugs (Medicare Part D)
Top drugs by claim count for calendar year 2023. Based on Medicare Part D data only.
What Mary Ernst, FNP prescribes most
Top Medicare Part D drugs by claim count, 2023
- Prednisone
Prednisone
84 claims
- Cefdinir 22
Cefdinir
22 claims
- Azithromycin 16
Azithromycin
16 claims
- Cephalexin 15
Cephalexin
15 claims
- Doxycycline Hyclate 13
Doxycycline Hyclate
13 claims
| Drug | Claims |
|---|---|
| Prednisone | 84 |
| Cefdinir | 22 |
| Azithromycin | 16 |
| Cephalexin | 15 |
| Doxycycline Hyclate | 13 |
* Counts below 11 are suppressed by CMS for patient privacy. Generic names shown where available from CMS Part D data.
Acute Care Nurse Practitioner Overview
How Mary Ernst, FNP fits within the Acute Care Nurse Practitioner landscape nationally.
24,697
Acute Care Nurse Practitioner Providers in US
53
States with Acute Care Nurse Practitioner
576
Avg Claims per Provider
Mary Ernst, FNP's 236 claims are below the specialty average of 576.
Nearby Acute Care Nurse Practitioner Providers in Missouri
Other clinicians with the same primary specialty enrolled in Missouri, drawn from the same CMS NPPES roster as Ernst.
Dr. Alivia Acklin
AG-ACNP
West Plains, MO
Dr. Michelle Adorjan
ACNP
Saint Louis, MO
Dr. Timothy Adrian
APRN
Saint Louis, MO
Dr. Jennifer Aiken
FNP-BC
Independence, MO
Dr. Hana Alul
NP
St. Louis, MO
Compare Acute Care Nurse Practitioner 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 Missouri medical board, federal registration is not a license check. Credential verification guide
- Weigh a second option: compare this provider with a nearby Acute Care Nurse Practitioner 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
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How to Find a Doctor
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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 Missouri
Frequently Asked Questions
What is Mary Ernst, FNP's specialty? ▼
Mary Ernst, FNP specializes in Acute Care Nurse Practitioner and practices in Saint Peters, Missouri. Credentials: FNP.
How much does Mary Ernst, FNP prescribe under Medicare Part D? ▼
In 2023, Mary Ernst, FNP wrote 236 Medicare Part D claims totaling $2K in drug costs for 157 beneficiaries.
Where is Mary Ernst, FNP located? ▼
Mary Ernst, FNP is located at 107 PIPER HILL DR, Saint Peters, MO, 63376. Phone: (636) 477-8757.
What is Mary Ernst, FNP's NPI number? ▼
Mary Ernst, FNP's National Provider Identifier (NPI) is 1487694659, issued on 06/07/2006.
How many Acute Care Nurse Practitioner providers are there in the US? ▼
There are 24,697 Acute Care Nurse Practitioner providers across 53 states in the US. The average Acute Care Nurse Practitioner provider writes 576 Medicare Part D claims per year.
What drugs does Mary Ernst, FNP prescribe most often? ▼
Based on 2023 Medicare Part D data, Mary Ernst, FNP's most frequently prescribed drugs include Prednisone, Cefdinir, Azithromycin. This reflects Medicare Part D prescriptions only and does not include commercial insurance or other payer types.
Does Mary Ernst, FNP accept Medicare? ▼
Mary Ernst, FNP appears in CMS Medicare data with 236 Part D claims and 157 Medicare beneficiaries in 2023. Contact the provider's office directly to confirm current Medicare enrollment and accepted plans.
How can I verify Mary Ernst, FNP's credentials? ▼
Mary Ernst, FNP's NPI is 1487694659 with credentials FNP. 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.