Mary Ernst, FNP
NPI 1487694659 · Nurse Practitioner · Saint Peters, MO
Enrolled with Medicare as Practitioner - Nurse Practitioner · source: CMS PECOS Public Provider Enrollment (2026.04.01)
Mary Ernst, FNP is a Nurse Practitioner provider in Saint Peters, MO (NPI 1487694659).
Provider details
- NPI number
- 1487694659
- Entity type
- Individual
- Primary specialty
- Nurse PractitionerPhysician Assistants & Advanced Practice Nursing Providers
- Credential
- FNP
- Sex
- Female
- Sole proprietor
- No
- License
- 2014010124 (MO)
Specialties & taxonomies
Physician Assistants & Advanced Practice Nursing Providers
Physician Assistants & Advanced Practice Nursing Providers
Physician Assistants & Advanced Practice Nursing Providers
Profile Score
A profile completeness & documented-activity index — NOT a quality, outcomes, or patient-satisfaction rating.
- Registry tenure28% of score
20 yrs in NPPES registry
- Profile completeness28% of score
100% of core fields populated
- Practice footprint17% of score
2 documented practice locations
- Medicare service volume (vs. specialty peers)28% of score
175 Medicare services, 2024 (ranked within specialty)
Medicare volume is ranked against active providers in the same specialty. Signals a provider has no public data for (e.g. Medicare claims) are left out of the score entirely — never counted as zero — so providers without that data are not penalized. See the full formula and weights in our methodology.
What this provider does (Medicare)
Based on Medicare fee-for-service claims, 2024; not all care is captured.
| Service (HCPCS) | Medicare services | Typical Medicare-allowed (2024) |
|---|---|---|
| Established Patient Office Or Other Outpatient Visit With Low Level OD Decision Making, If Using Time, 20 Minutes Or More99213 | 124 | $74 |
| Urinalysis, Manual Test81002 | 19 | $3 |
| Detection Test By Immunoassay With Direct Visual Observation for Streptococcus, Group a (strep)87880 | 17 | $16 |
| Detection Test By Immunoassay Technique for Severe Acute Respiratory Syndrome Coronavirus and Influenza87428 | 15 | $69 |
Typical Medicare-allowed amounts for these services range $3–$74 (2024). The Medicare-allowed amount is what Medicare recognizes for a service under fee-for-service — a reference figure for 2024, not a price quote and not what you would be billed. Medicare Part B covers roughly an eighth of all NPIs (65+ skew); services with fewer than 11 beneficiaries are suppressed by CMS. Source: CMS Medicare Physician & Other Practitioners, by Provider & Service.
What this provider prescribes (Medicare Part D)
Top drugs by Medicare Part D claim volume, 2024 · 6 distinct drugs on file.
| Drug | Part D claims (2024) | Beneficiaries |
|---|---|---|
| Prednisone | 110 | 105 |
| Cefdinir | 37 | 37 |
| Nitrofurantoin Monohyd/M-Crystbrand: Nitrofurantoin Mono-Macro | 28 | 27 |
| Cephalexin | 27 | 27 |
| Azithromycin | 22 | 22 |
| Doxycycline Hyclate | 19 | 19 |
Medicare Part D only. These counts cover prescriptions paid through Medicare Part D in 2024 — they do notinclude cash-pay, commercial-insurance, Medicaid, or Part B–administered drugs, and badly undercount high cash-pay categories (e.g. GLP-1 weight-loss, testosterone, and ED medications). Any drug with 10 or fewer claims is omitted by CMS, and beneficiary counts under 11 are suppressed — so a missing drug means , never zero. This is a factual claims summary, not an endorsement, not medical advice, and not a consumer report. Source: CMS Medicare Part D Prescribers — by Provider and Drug.
Practice location
Mailing address
Additional practice locations (1)
- 1520 Wentzville PkwyWentzville, MO 63385-3408Phone: (636) 497-4060
Registry dates
- Enumerated
- 2006-06-07
- Last updated
- 2022-05-03
- Certified
- 2022-05-03
Frequently asked questions
- What is Mary Ernst's NPI number?
- Mary Ernst's National Provider Identifier (NPI) is 1487694659, a unique 10-digit ID issued by CMS for use in standard healthcare transactions.
- What is Mary Ernst's specialty?
- Mary Ernst is listed in the NPPES registry with a primary specialty of Nurse Practitioner (Physician Assistants & Advanced Practice Nursing Providers).
- Where is Mary Ernst located?
- Mary Ernst's practice location on file with NPPES is 107 Piper Hill Dr, Saint Peters, MO 63376-1620.
- What is Mary Ernst's phone number?
- The practice phone number listed in the NPPES registry for Mary Ernst is (636) 477-8757.
- Does Mary Ernst accept Medicare?
- Mary Ernst is approved to bill Medicare according to CMS PECOS enrollment data (2026.04.01). Confirm current participation with the provider before scheduling.
- Is Mary Ernst's NPI active?
- Yes — Mary Ernst's NPI (1487694659) is active in the NPPES registry as of the last update on 2022-05-03.
Source: CMS NPPES Data Dissemination (June 2026). NPI Central is not affiliated with CMS. Data is provided as-is from the public registry.