Joan Mass, MD
NPI 1295708162 · Internal Medicine Physician · Saint Charles, MO
Enrolled with Medicare as Practitioner - Internal Medicine · source: CMS PECOS Public Provider Enrollment (2026.04.01)
Joan Mass, MD is a Internal Medicine Physician provider in Saint Charles, MO (NPI 1295708162).
Provider details
- NPI number
- 1295708162
- Entity type
- Individual
- Primary specialty
- Internal Medicine PhysicianAllopathic & Osteopathic Physicians
- Credential
- MD
- Sex
- Female
- Sole proprietor
- No
- License
- R9A66 (MO)
Specialties & taxonomies
Allopathic & Osteopathic Physicians
Allopathic & Osteopathic Physicians
Profile Score
A profile completeness & documented-activity index — NOT a quality, outcomes, or patient-satisfaction rating.
- Registry tenure38% of score
20 yrs in NPPES registry
- Profile completeness38% of score
100% of core fields populated
- Practice footprint23% of score
1 documented practice location
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.
Practice location
Mailing address
Registry dates
- Enumerated
- 2006-02-09
- Last updated
- 2012-05-04
Frequently asked questions
- What is Joan Mass's NPI number?
- Joan Mass's National Provider Identifier (NPI) is 1295708162, a unique 10-digit ID issued by CMS for use in standard healthcare transactions.
- What is Joan Mass's specialty?
- Joan Mass is listed in the NPPES registry with a primary specialty of Internal Medicine Physician (Allopathic & Osteopathic Physicians).
- Where is Joan Mass located?
- Joan Mass's practice location on file with NPPES is 300 1st Capitol Dr, Saint Charles, MO 63301-2844.
- What is Joan Mass's phone number?
- The practice phone number listed in the NPPES registry for Joan Mass is (636) 947-5000.
- Does Joan Mass accept Medicare?
- Joan Mass is approved to bill Medicare according to CMS PECOS enrollment data (2026.04.01). Confirm current participation with the provider before scheduling.
- Is Joan Mass's NPI active?
- Yes — Joan Mass's NPI (1295708162) is active in the NPPES registry as of the last update on 2012-05-04.
Source: CMS NPPES Data Dissemination (June 2026). NPI Central is not affiliated with CMS. Data is provided as-is from the public registry.