Mark Nelson, MD
NPI 1538140090 · Rheumatology Physician · San Antonio, TX
Enrolled with Medicare as Practitioner - Rheumatology · source: CMS PECOS Public Provider Enrollment (2026.04.01)
Mark Nelson, MD is a Rheumatology Physician provider in San Antonio, TX (NPI 1538140090).
Provider details
- NPI number
- 1538140090
- Entity type
- Individual
- Primary specialty
- Rheumatology PhysicianAllopathic & Osteopathic Physicians
- Credential
- MD
- Sex
- Male
- Sole proprietor
- Yes
- License
- G7857 (TX)
Specialties & taxonomies
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
- 2005-11-10
- Last updated
- 2007-10-22
Frequently asked questions
- What is Mark Nelson's NPI number?
- Mark Nelson's National Provider Identifier (NPI) is 1538140090, a unique 10-digit ID issued by CMS for use in standard healthcare transactions.
- What is Mark Nelson's specialty?
- Mark Nelson is listed in the NPPES registry with a primary specialty of Rheumatology Physician (Allopathic & Osteopathic Physicians).
- Where is Mark Nelson located?
- Mark Nelson's practice location on file with NPPES is 3338 Oakwell Court, San Antonio, TX 78218-3019.
- What is Mark Nelson's phone number?
- The practice phone number listed in the NPPES registry for Mark Nelson is (210) 656-5000.
- Does Mark Nelson accept Medicare?
- Mark Nelson is approved to bill Medicare according to CMS PECOS enrollment data (2026.04.01). Confirm current participation with the provider before scheduling.
- Is Mark Nelson's NPI active?
- Yes — Mark Nelson's NPI (1538140090) is active in the NPPES registry as of the last update on 2007-10-22.
Source: CMS NPPES Data Dissemination (June 2026). NPI Central is not affiliated with CMS. Data is provided as-is from the public registry.