Provider records sourced from NPPES (CMS National Plan & Provider Enumeration System). Data current as of August 10, 2026.
NPIDirectory

Mrs. Mary B Ernst, FNP

Individual provider Acute Care Nurse Practitioner · NPI 1487694659

Mrs. Mary B Ernst, FNP is a Nurse Practitioner in Saint Peters, Missouri. Qualified in 1998, 28 years ago. Practices with Physician Groups Lc, a 524-clinician group, works from 2 locations and accepts Medicare assignment. Licensed in Missouri.

Years since qualifying
28
Licensed in
MO
In the registry since
2006
Specialties on file
3
What do these letters mean?
FNP — Family Nurse Practitioner
A nurse practitioner who treats patients of all ages, much like a family doctor.

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Practice location Address checks out

107 Piper Hill Dr
Saint Peters, MO 63376-1620
Phone: (636) 477-8757
Fax: (314) 219-6241
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Pin is approximate — placed at the ZIP-code centre, not the exact door.

Additional practice locations (1)

  • 1520 Wentzville Pkwy, Wentzville, MO 63385-3408 — (636) 497-4060

Specialties & licences

Nurse Practitioner (primary) Taxonomy 363L00000X · Licence 2014010124 (MO)
Acute Care Nurse Practitioner Taxonomy 363LA2100X · Licence 2014010124 (MO)
Acute Care Nurse Practitioner Taxonomy 363LA2100X · Licence 073032 (MO)

Record details

NPI number1487694659
Entity typeIndividual (Type 1)
GenderFemale
Credentials FNP
Sole proprietorNo
NPI enumeratedJune 7, 2006
Last updated in NPPESMay 3, 2022
Certification dateMay 3, 2022

Medicare enrollment

From the CMS Doctors & Clinicians file — this clinician is enrolled in Medicare.

Medicare specialtyNURSE PRACTITIONER
Medical schoolOTHER
Graduated 1998 (28 years in practice)
Group practice Physician Groups Lc — 524 clinicians
Accepts Medicare assignment Yes — accepts the Medicare-approved amount
Practice locations3 on file with Medicare

Medicare patients and services, 2024

From the CMS Medicare Physician & Other Practitioners file for calendar year 2024. It counts Original Medicare patients only, so a practice that mostly sees Medicare Advantage or privately insured patients looks smaller here than it is.

Medicare patients116
Services billed 262 a service is one billed item, such as a visit, a test or a procedure
Average patient age74

Dollar amounts are not shown. What Medicare pays a practice is gross billings, before staff, premises and tax and including the cost of any drugs it administers, so it is not what a clinician earns.

Payments from drug and device companies, 2025

Drug and device makers are required by federal law (the Physician Payments Sunshine Act) to report what they pay or give to clinicians, and CMS publishes the reports as Open Payments. This is the 2025 program year. A report is a record of a payment, not an allegation of anything, and many are small items such as meals. Only general payments are listed here; research payments and ownership or investment interests are reported separately by CMS and are not shown.

Food and Beverage $32 2 payments · a meal or drink at a meeting or visit, not a fee

Each amount is the sum of what companies reported for that kind of payment in 2025, rounded to the dollar. Not all of it is income to the clinician: a meal is not a fee, a charitable contribution goes to a charity, and a royalty or an acquisition payment is not a salary.

Check a report, or dispute one, at the source in CMS’s own tool, Open Payments. Corrections go through CMS’s dispute process. This site removes a home address on request and asks for no proof, because that is privacy; it will not remove an accurate payment report on request, because that is a statutory public disclosure.

Colleagues at Physician Groups Lc

Clinicians the CMS Doctors & Clinicians file lists under the same group practice. CMS counts 524 clinicians in the practice; 12 are shown here.

Other providers in Saint Peters