John Spencer Mays, MD
Internal Medicine (CMS) · Saint Louis, MO
At a glance
1044 N Mason Rd, Saint Louis, MO 63141-6431
NPPES record updated Sep 1, 2026. Public records can lag behind changes at a practice.
Before you call: a quick checklist
- Are you accepting new patients?
- Do you accept my specific insurance plan?
- Do you provide the service I need at this address?
- Do I need a referral, and what is the earliest appointment?
Insurance participation and appointment availability are not established by these public records.
Medicare & insurance
Insurance participation is not established by these public records. Ask the practice and your insurer about your specific plan and this location.
How to check your coverage
Use your plan’s provider directory or the member-services number on your insurance card. Confirm the clinician, practice address, service, and whether a referral is required. A missing opt-out record does not establish Medicare acceptance.
Check the official Medicare directory ↗Practice location
1044 N Mason Rd Div Im General Med, Ste 330Saint Louis, MO 63141-6431
Education & affiliations
- Medical / professional school
- University Of Tennessee, Hsc, College Of Medicine
- Graduation year
- 2018
- CMS specialties
- Internal Medicine
CMS reports telehealth services for this clinician. Confirm current services and availability with the practice.
Practice groups
- Arnold Physical Therapy And Sports Medicine Llc
- Elite Physical Therapy Of Creve Coeur Llc
- Physical Therapy Spine And Sports Medicine Llc
- Physician Groups Lc
Reported hospital affiliations
- Alton Memorial Hospital Alton, IL
- Barnes Jewish Hospital Saint Louis, MO
- Barnes-Jewish West County Hospital Creve Coeur, MO
- Christian Hospital Northeast Saint Louis, MO
- Missouri Baptist Medical Center Saint Louis, MO
Graduation year does not establish years in practice. A reported affiliation does not establish employment, current admitting privileges, or insurance participation.
Source: CMS National Downloadable File · Published Oct 15, 2026.
Source: CMS Facility Affiliation Data · Published Oct 15, 2026.
Procedures in the public data
Reported activity can help you ask more informed questions about a practice’s services.
No displayed procedure-category record in this release. This does not mean the clinician performs no procedures.
CMS uses a one-year claims window with a reporting lag. Counts cover the Medicare activity included by CMS, not all patients. “1–10” is a published range. Volume is not a quality or outcomes score. Coverage and methodology
Source: CMS Utilization Data · Published Oct 15, 2026.
Find providers with a similar service mix
Compare 2024 published Medicare activity in the same reported specialty, here or in another city.
Industry-reported general payments
Includes reported transfers of value, such as meals, travel, or consulting. Payments do not establish improper conduct or quality of care. Research funding and ownership values are excluded from this total.
See payment purposes and reporting companies
Reported purposes
| Purpose | Amount |
|---|---|
| Food and beverage | $234.66 |
Reporting companies
| Company | Amount |
|---|---|
| NOVARTIS PHARMACEUTICALS CORPORATION | $44.90 |
| GLAXOSMITHKLINE, LLC. | $28.72 |
| LILLY USA, LLC | $21.98 |
| MEDTRONIC, INC. | $21.56 |
| ESPERION THERAPEUTICS, INC. | $19.35 |
| BOEHRINGER INGELHEIM PHARMACEUTICALS, INC. | $18.39 |
| HEARTFLOW, INC. | $17.16 |
| ABBOTT LABORATORIES | $16.70 |
| Other reporting companies | $45.90 |
Source: CMS 2025 payments grouped by covered recipient and nature of payments · Published Jun 30, 2026.
Professional details: NPI, taxonomy & registry record
Registry details
- Primary taxonomy
- Internal Medicine (CMS)
- Taxonomy code
- 208D00000X
- Enumeration date
- Jun 21, 2018
- Record updated
- Sep 1, 2026
More registry details
- Provider type
- Individual · Type 1
- Reported credentials
- MD
Reported taxonomies and licenses
207R00000X
License reported: 2020001817 MO
208D00000X · Primary
License reported: 2020001817 MO
License numbers and credentials are reported to NPPES; HCPList does not independently verify them.
Practice location
1044 N Mason RdDiv Im General Med, Ste 330
Saint Louis, MO 63141-6431
- Phone
- (314) 996-8103
- Fax
- (314) 996-3230
Mailing address
PO BOX 7412011CHICAGO, IL 606742011
Information may be outdated or incomplete. Confirm details directly with the practice. HCPList is an independent directory and is not affiliated with CMS.
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