John Wallmark, M.D.
NPI 1689755365 · Hematology & Oncology Physician · Rockville, MD
Enrolled with Medicare as Practitioner - Hematology/Oncology · source: CMS PECOS Public Provider Enrollment (2026.04.01)
John Wallmark, M.D. is a Hematology & Oncology Physician provider in Rockville, MD (NPI 1689755365).
Provider details
- NPI number
- 1689755365
- Entity type
- Individual
- Primary specialty
- Hematology & Oncology PhysicianAllopathic & Osteopathic Physicians
- Credential
- M.D.
- Sex
- Male
- Sole proprietor
- No
- License
- D0053177 (MD)
Specialties & taxonomies
Allopathic & Osteopathic Physicians
Profile Score
A profile completeness & documented-activity index — NOT a quality, outcomes, or patient-satisfaction rating.
- Registry tenure25% of score
19 yrs in NPPES registry
- Profile completeness25% of score
100% of core fields populated
- Practice footprint15% of score
1 documented practice location
- Medicare service volume (vs. specialty peers)25% of score
12,247 Medicare services, 2024 (ranked within specialty)
- Open Payments transparency10% of score
Has Open Payments disclosures (2024)
Medicare volume is ranked against active providers in the same specialty. Signals a provider has no public data for (e.g. Medicare claims) are left out of the score entirely — never counted as zero — so providers without that data are not penalized. See the full formula and weights in our .
What this provider does (Medicare)
Based on Medicare fee-for-service claims, 2024; not all care is captured.
| Service (HCPCS) | Medicare services | Typical Medicare-allowed (2024) |
|---|---|---|
| Complete Blood Cell Count (red Cells, White Blood Cell, Platelets), Automated Test and Automated Differential White Blood Cell Count85025 | 2,168 | $8 |
| Blood Test, Comprehensive Group of Blood Chemicals80053 | 1,945 | $10 |
| Gammaglobulin (immune System Protein) Measurement82784 | 894 | $9 |
| Flow Cytometry Technique for Dna Or Cell Analysis, Each Additional Marker88185 | 884 | $28 |
| Established Patient Office Or Other Outpatient Visit With Moderate Level of Decision Making, If Using Time, 30 Minutes Or More99214 | 872 | $143 |
| Injection of Additional New Drug Or Substance Into Vein96375 | 461 |
What this provider prescribes (Medicare Part D)
Top drugs by Medicare Part D claim volume, 2024 · 31 distinct drugs on file.
| Drug | Part D claims (2024) | Beneficiaries |
|---|---|---|
| Letrozole | 205 | 58 |
| Rivaroxabanbrand: Xarelto | 56 | 20 |
| Anastrozole | 55 | 20 |
| Warfarin Sodium | 49 | — |
| Acyclovir | 38 | — |
| Everolimus | 27 | — |
| Lenalidomidebrand: Revlimid | 27 | — |
| Abemaciclib |
Transparency — industry payments
Based on CMS Open Payments, 2024; not all care is captured.
$2,630 across 67 records (Open Payments 2024)
Open Payments discloses payments and transfers of value (meals, travel, consulting, research, royalties) from drug and device makers to providers. This is a transparency signal, not a verdict — such payments are legal and common, and their presence is neither an endorsement nor a criticism. Source: CMS Open Payments, program year 2024.
Practice location
Mailing address
Registry dates
- Enumerated
- 2006-10-18
- Last updated
- 2012-08-01
Frequently asked questions
- What is John Wallmark's NPI number?
- John Wallmark's National Provider Identifier (NPI) is 1689755365, a unique 10-digit ID issued by CMS for use in standard healthcare transactions.
- What is John Wallmark's specialty?
- John Wallmark is listed in the NPPES registry with a primary specialty of Hematology & Oncology Physician (Allopathic & Osteopathic Physicians).
- Where is John Wallmark located?
- John Wallmark's practice location on file with NPPES is 9707 Medical Center Dr, Rockville, MD 20850-3348.
- What is John Wallmark's phone number?
- The practice phone number listed in the NPPES registry for John Wallmark is (301) 424-6231.
- Does John Wallmark accept Medicare?
- John Wallmark is approved to bill Medicare according to CMS PECOS enrollment data (2026.04.01). Confirm current participation with the provider before scheduling.
- Is John Wallmark's NPI active?
- Yes — John Wallmark's NPI (1689755365) is active in the NPPES registry as of the last update on 2012-08-01.
Source: CMS NPPES Data Dissemination (June 2026). NPI Central is not affiliated with CMS. Data is provided as-is from the public registry.