Quick answers
- Does Nathaniel C. Oncken accept Medicare assignment?
- Yes. Medicare's clinician data says Nathaniel C. Oncken accepts Medicare assignment (the Medicare-approved amount as full payment for covered services), as of October 2, 2026. Ask the office to confirm before your visit.
- How many Medicare patients does Nathaniel C. Oncken see?
- In 2024, CMS data shows 130 Original Medicare patients and 1,087 services for Nathaniel C. Oncken. This counts Original Medicare only and measures volume, not quality.
- What is Nathaniel C. Oncken's NPI number?
- 1447211214. The NPI (National Provider Identifier) is the clinician's permanent federal ID; you can look it up in the official NPI Registry.
Medicare activity in 2024
Official CMS public-use data for Nathaniel C. Oncken, data year 2024 (released May 21, 2026). It covers Original Medicare (fee-for-service) patients only, not Medicare Advantage or other insurance. It shows volume, not quality or outcomes. CMS hides any count of 10 or fewer patients.
| Original Medicare patients | 130 |
|---|---|
| Services billed to Medicare | 1,087 |
| Different services or procedures | 3 |
| Participating Medicare provider | Yes |
| Average age of these patients | 71 |
Most frequent services
- Chiropractic manipulative treatment, 3-4 spinal regions (98941)1,062 services
Chronic conditions among these patients
Share of this clinician’s Original Medicare patients with each condition, as published by CMS (it describes the patients, not the care given).
- High cholesterol72%
- High blood pressure63%
- Arthritis40%
- Diabetes33%
- Anxiety24%
- Depression22%
Practice locations
Addresses where Nathaniel C. Oncken is enrolled with Medicare (CMS data updated October 2, 2026).
- 423 Calhoun Ave, BGreenwood, SC 29649 (864) 223‑2224
Specialties
- Chiropracticprimary
Other chiropractors in Greenwood
Clinicians with the same Medicare primary specialty in Greenwood, SC — not a recommendation.
Clinician information
| Credential | DC |
|---|---|
| Chiropractic college | Sherman College Of Straight Chiropractic |
| Graduation year | 2005 (21 years since chiropractic college) |
| Gender (as listed) | Male |
| Medicare assignment | Accepts (Medicare-approved amount as full payment) |
| NPI (National Provider Identifier) | 1447211214 |
| Corrections | Report an error or suggest an update → |
Most corrections must be made at the source: clinicians update their NPI Registry record (NPPES) and their Medicare enrollment (PECOS); this page follows the next data release.
Sources
- National Downloadable File (Doctors and Clinicians) — CMS, data updated October 2, 2026, retrieved October 29, 2026
- Medicare Physician & Other Practitioners - by Provider — CMS, data year 2024, released May 21, 2026; Medicare Physician & Other Practitioners - by Provider and Service
- NPI Registry — U.S. Department of Health and Human Services (NPPES), the clinician’s official record
- Medicare Care Compare — official Medicare tool to look up clinicians