DR. MARK JOSEPH FESLER (MD) – Hematology & Oncology Physician, NPI 1235204066
Hematology & Oncology Physician
Main info
Doctor Profile
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Profile Insights
NPPES metrics only — not quality of care.
310 HEMATOLOGY/ONCOLOGY in MO
Provider Addresses for DR. MARK JOSEPH FESLER (MD)
3655 VISTA AVE
SAINT LOUIS, MO 631102539
Phone: (314) 977-4340
Fax: (314) 776-2287
Type: Mailing
625, North Albion Street, Denver, Colorado, 80220, United States
DENVER, CO 802204917
Phone: (720) 317-3381
Type: Mailing
NPPES updates history
No NPPES updates recorded for this provider.
Prescription Activity
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Open Payments (CMS)
CMS reports 258 Open Payments records for all available years, with a total value of $338,365.
Total Amount is formed as General ($338,365) + Research ($0) + Ownership ($0) = $338,365.
Last reported payment date: 2024-12-23 • Largest payer in this snapshot: ABBVIE INC. ($56,674).
Total Amount
$338,365
General + Research + Ownership
Payments
258
Total payment records
General Amount
$338,365
General payments
Research Amount
$0
Research funding
Ownership Amount
$0
Ownership interests
Ownership Count
0
Ownership records
Last Payment Date
2024-12-23
Latest reported date
Top Companies
Largest payers in this snapshot
| Company | Amount |
|---|---|
| ABBVIE INC. | $56,674 |
| Incyte Corporation | $55,538 |
| Genentech USA, Inc. | $41,242 |
| GENZYME CORPORATION | $36,263 |
| BeiGene USA, Inc. | $34,063 |
Medicare Enrollment & Revalidation
Source: CMS public data · Not endorsed by CMS ·
Educational use only—not medical, billing, or legal advice.
PECOS enrollment status
Participating (accepts Medicare assignment)
Enrollment effective: 2010-08-12
PECOS data refreshed: 2026-05-27
Medicare revalidation (CMS due date list)
Due date not assigned yet
CMS is tracking this Medicare enrollment for revalidation, but has not published a due date.
Enrollment records
1
Earliest due date
Not assigned (TBD)
CMS data updated
2026-06-01
Revalidation progress
- Medicare enrolled
- On CMS revalidation list
- Due date assigned
- Revalidate in PECOS
CMS enrollment records
| Enrollment ID | Type | Specialty | State | Due date |
|---|---|---|---|---|
| I20100812000917 | I | Hematology/Oncology | MO | TBD |
What to do next
- No action required while the due date shows TBD.
- Check the CMS Revalidation Lookup Tool periodically — CMS updates the list about every 60 days.
- Do not submit a revalidation application in PECOS until CMS publishes a concrete due date.
Prepare CMS-855 application → · Look up this NPI in PECOS → · Verify on CMS PECOS
Medicare Utilization (FFS)
Source: CMS public data · Not endorsed by CMS · Beneficiary counts under 11 are suppressed in source data ·
Educational use only—not medical, billing, or legal advice.
Top Medicare procedures (2023) · refreshed 2026-05-27
| HCPCS | Description | Services | Beneficiaries | Medicare allowed |
|---|---|---|---|---|
| 99215 | Established patient office or other outpatient visit, 40-54 minutes | 733 | 184 | $0 |
| 99233 | Subsequent hospital care with moderate levelof medical decision making, if using time, at least 50 minutes | 300 | 58 | $0 |
| 99223 | Initial hospital care with moderate level of medical decision making, if using time, at least 75 minutes | 89 | 59 | $0 |
| 99205 | New patient office or other outpatient visit, 60-74 minutes | 28 | 28 | $0 |
Insurance plans in this area (ZIP 63110)
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Group practice members
| Name | Specialty | State |
|---|---|---|
| Medical Oncology, Hematology | MO | |
| Nurse Practitioner | MO | |
| H E M A T O L O G Y/ O N C O L O G Y | MO | |
| Hematology/Oncology, Internal Medicine | MO | |
| Hospitalist, Internal Medicine | MO | |
| Internal Medicine | MO | |
| Nurse Practitioner | MO | |
| Hematology/Oncology, Hematology, Hospitalist, Internal Medicine | CT |
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