Mark Castellaw, MD
NPI 1114928793 · Internal Medicine Physician · Germantown, TN
Enrolled with Medicare as Practitioner - Internal Medicine · source: CMS PECOS Public Provider Enrollment (2026.04.01)
Mark Castellaw, MD is a Internal Medicine Physician provider in Germantown, TN (NPI 1114928793).
Provider details
- NPI number
- 1114928793
- Entity type
- Individual
- Primary specialty
- Internal Medicine PhysicianAllopathic & Osteopathic Physicians
- Credential
- MD
- Sex
- Male
- Sole proprietor
- No
- License
- 14060 (TN)
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
20 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
19,441 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) |
|---|---|---|
| Insertion of Needle Into Vein for Collection of Blood Sample36415 | 2,140 | $9 |
| Established Patient Office Or Other Outpatient Visit With Moderate Level of Decision Making, If Using Time, 30 Minutes Or More99214 | 1,877 | $117 |
| Blood Test, Lipids (cholesterol and Triglycerides)80061 | 1,383 | $13 |
| Complete Blood Cell Count (red Cells, White Blood Cell, Platelets), Automated Test and Automated Differential White Blood Cell Count85025 | 1,326 | $8 |
| Visit Complexity Inherent to Evaluation and Management Associated With Medical Care Services That Serve As the Continuing Focal Point for All Needed Health Care Services And/Or With Medical Care Services That Are Part of Ongoing Care Related to a Patient'SG2211 | 1,211 | $15 |
| Vitamin D-3 Level |
What this provider prescribes (Medicare Part D)
Top drugs by Medicare Part D claim volume, 2024 · 139 distinct drugs on file.
| Drug | Part D claims (2024) | Beneficiaries |
|---|---|---|
| Amlodipine Besylate | 591 | 181 |
| Atorvastatin Calcium | 537 | 154 |
| Levothyroxine Sodium | 535 | 141 |
| Losartan Potassium | 502 | 158 |
| Rosuvastatin Calcium | 494 | 152 |
| Pantoprazole Sodium | 478 | 135 |
| Ezetimibe |
Transparency — industry payments
Based on CMS Open Payments, 2024; not all care is captured.
$551 across 28 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
- 2005-08-09
- Last updated
- 2016-10-25
Frequently asked questions
- What is Mark Castellaw's NPI number?
- Mark Castellaw's National Provider Identifier (NPI) is 1114928793, a unique 10-digit ID issued by CMS for use in standard healthcare transactions.
- What is Mark Castellaw's specialty?
- Mark Castellaw is listed in the NPPES registry with a primary specialty of Internal Medicine Physician (Allopathic & Osteopathic Physicians).
- Where is Mark Castellaw located?
- Mark Castellaw's practice location on file with NPPES is 8040 Wolf River Boulevard, Germantown, TN 38138-1775.
- What is Mark Castellaw's phone number?
- The practice phone number listed in the NPPES registry for Mark Castellaw is (901) 726-0200.
- Does Mark Castellaw accept Medicare?
- Mark Castellaw is approved to bill Medicare according to CMS PECOS enrollment data (2026.04.01). Confirm current participation with the provider before scheduling.
- Is Mark Castellaw's NPI active?
- Yes — Mark Castellaw's NPI (1114928793) is active in the NPPES registry as of the last update on 2016-10-25.
Source: CMS NPPES Data Dissemination (June 2026). NPI Central is not affiliated with CMS. Data is provided as-is from the public registry.