Quick answers
- Does William T. Dierenfeldt accept Medicare assignment?
- Yes. Medicare's clinician data says William T. Dierenfeldt 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 William T. Dierenfeldt see?
- In 2024, CMS data shows 742 Original Medicare patients and 1,272 services for William T. Dierenfeldt. This counts Original Medicare only and measures volume, not quality.
- What is William T. Dierenfeldt's NPI number?
- 1477591634. 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 William T. Dierenfeldt, 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 | 742 |
|---|---|
| Services billed to Medicare | 1,272 |
| Different services or procedures | 35 |
| Participating Medicare provider | Yes |
| Average age of these patients | 72 |
Most frequent services
- Removal of polyps or growths of large bowel using an endoscope with mechanical snare (45385)270 services
- Biopsy of esophagus, stomach, and/or upper small bowel using a flexible endoscope (43239)254 services
- Colorectal cancer screening; colonoscopy on individual at high risk (G0105)98 services
- Biopsy of large bowel using a flexible endoscope (45380)86 services
- Balloon dilation of esophagus, stomach, and/or upper small bowel using a flexible endoscope, less than 3.0 cm (43249)73 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%
- Arthritis43%
- Depression31%
- Diabetes27%
- Anxiety27%
Hospitals where William T. Dierenfeldt works
Medicare's Facility Affiliation Data lists William T. Dierenfeldt 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.
- Ascension Via Christi Hospital Manhattan, IncManhattan, KS · Acute Care Hospital · Medicare rating: 4 of 5 stars · Emergency services: listed by Medicare · CCN 170142
- Clay County Medical CenterClay Center, KS · Critical Access Hospital · Medicare rating: 3 of 5 stars · Emergency services: listed by Medicare · CCN 171371
- Community Memorial Healthcare, Inc.Marysville, KS · Critical Access Hospital · Medicare rating: 4 of 5 stars · Emergency services: listed by Medicare · CCN 171363
- Manhattan Surgical Hospital LLCManhattan, KS · Acute Care Hospital · Emergency services: not listed by Medicare · CCN 170190
- Stormont Vail Health Flint Hills, LLCJunction City, KS · Acute Care Hospital · Medicare rating: 4 of 5 stars · Emergency services: listed by Medicare · CCN 170074
Practice locations
Addresses where William T. Dierenfeldt is enrolled with Medicare (CMS data updated October 2, 2026).
- 1325 Research Park DrManhattan, KS 66502 (785) 270‑8723
- 1500 SW 10h AveTopeka, KS 66604 (785) 354‑6000
- 1823 College AveManhattan, KS 66502 (785) 354‑9591
- 901 SW Garfield AveTopeka, KS 66606 (785) 354‑9591
Group practices
Medicare enrollment lists William T. Dierenfeldt as a member of this group (CMS data updated October 2, 2026).
- Cotton-O'neil Clinic Revocable Trust666 clinicians in the group
Specialties
- Gastroenterologyprimary
Other gastroenterologists in Manhattan
Clinicians with the same Medicare primary specialty in Manhattan, KS — not a recommendation.
Other clinicians in Cotton-O'neil Clinic Revocable Trust
Medicare enrollment lists these clinicians in the same group practice — not a recommendation.
Clinician information
| Credential | MD |
|---|---|
| Medical school | University Of Missouri, Kansas City, School Of Medicine |
| Graduation year | 1994 (32 years since medical school) |
| Gender (as listed) | Male |
| Medicare assignment | Accepts (Medicare-approved amount as full payment) |
| NPI (National Provider Identifier) | 1477591634 |
| 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
- Facility Affiliation Data — Centers for Medicare & Medicaid Services (CMS), data updated October 2, 2026, retrieved October 29, 2026
- Hospital General Information — CMS, data updated October 26, 2026, retrieved November 13, 2026
- 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