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Internal Medicine

Wilhelm L. Castellon, DO

Works at hospitals in Chillicothe, OH · Ohio

Summary

Dr. Wilhelm L. Castellon, DO is an internal medicine doctor at 272 Hospital Rd, Chillicothe, OH 45601. Phone: (740) 779-7500. Accepts Medicare assignment. In 2024, Wilhelm L. Castellon had 223 Original Medicare patients and 571 services. NPI 1821471327. Source: CMS National Downloadable File, updated October 2, 2026; CMS Facility Affiliation Data, updated October 2, 2026; CMS Medicare Physician & Other Practitioners, data year 2024.

  • Specialty: Internal medicine doctor (Medicare lists Internal Medicine)
  • Address: 272 Hospital Rd, Chillicothe, OH 45601 · Directions (1 more location)
  • Phone: (740) 779‑7500
  • Medicare: Accepts Medicare assignment
  • Hospital: Adena Regional Medical Center
  • Group practice: Hospitalist Medicine Physicians of Ohio-Columbus II Professional Corp
  • Medical school: Lake Erie College Of Osteopathic Medicine, Erie · graduated 2014 (12 years since medical school)
  • Gender (as listed): Male

From official Medicare data

This page shows what Medicare's official clinician data says about Wilhelm L. Castellon, joined by NPI number (data updated October 2, 2026). It is not a recommendation or a rating. Call the office or hospital to confirm before you go.

In a medical emergency, call 911.

Quick answers

Does Wilhelm L. Castellon accept Medicare assignment?
Yes. Medicare's clinician data says Wilhelm L. Castellon 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 Wilhelm L. Castellon see?
In 2024, CMS data shows 223 Original Medicare patients and 571 services for Wilhelm L. Castellon. This counts Original Medicare only and measures volume, not quality.
What is Wilhelm L. Castellon's NPI number?
1821471327. 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 Wilhelm L. Castellon, 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 patients223
Services billed to Medicare571
Different services or procedures10
Participating Medicare providerYes
Average age of these patients76

Most frequent services

  1. Subsequent hospital care with moderate levelof medical decision making, if using time, at least 50 minutes (99233)250 services
  2. Hospital discharge day management, more than 30 minutes (99239)145 services
  3. Initial hospital care with moderate level of medical decision making, if using time, at least 75 minutes (99223)86 services
  4. Subsequent hospital care with moderate levelof medical decision making, if using time, at least 35 minutes (99232)45 services
  5. Advance care planning, first 30 minutes (99497)18 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 blood pressure75%
  • High cholesterol75%
  • Arthritis57%
  • Diabetes44%
  • Ischemic heart disease44%
  • Heart failure44%

Hospitals where Wilhelm L. Castellon works

Medicare's Facility Affiliation Data lists Wilhelm L. Castellon at these hospitals (updated October 2, 2026). Each hospital page shows its address, phone, emergency services, Medicare rating and all its clinicians. Star rating and emergency services: Hospital General Information (CMS), data updated October 26, 2026.

Practice locations

Addresses where Wilhelm L. Castellon is enrolled with Medicare (CMS data updated October 2, 2026).

Group practices

Medicare enrollment lists Wilhelm L. Castellon as a member of this group (CMS data updated October 2, 2026).

  • Hospitalist Medicine Physicians of Ohio-Columbus II Professional Corp70 clinicians in the group

Specialties

Find other Internal Medicine doctors in Ohio →

Other internal medicine doctors in Chillicothe

Clinicians with the same Medicare primary specialty in Chillicothe, OH — not a recommendation.

All internal medicine doctors in Chillicothe →

Other clinicians in Hospitalist Medicine Physicians of Ohio-Columbus II Professional Corp

Medicare enrollment lists these clinicians in the same group practice — not a recommendation.

Clinician information

CredentialDO
Medical schoolLake Erie College Of Osteopathic Medicine, Erie
Graduation year2014 (12 years since medical school)
Gender (as listed)Male
Medicare assignmentAccepts (Medicare-approved amount as full payment)
NPI (National Provider Identifier)1821471327
CorrectionsReport 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

  1. Facility Affiliation Data — Centers for Medicare & Medicaid Services (CMS), data updated October 2, 2026, retrieved October 29, 2026
  2. Hospital General Information — CMS, data updated October 26, 2026, retrieved November 13, 2026
  3. National Downloadable File (Doctors and Clinicians) — CMS, data updated October 2, 2026, retrieved October 29, 2026
  4. Medicare Physician & Other Practitioners - by Provider — CMS, data year 2024, released May 21, 2026; Medicare Physician & Other Practitioners - by Provider and Service
  5. NPI Registry — U.S. Department of Health and Human Services (NPPES), the clinician’s official record
  6. Medicare Care Compare — official Medicare tool to look up clinicians