John Clark, M.D.
NPI 1578631784 · Nephrology Physician · Huntsville, AL
Enrolled with Medicare as Practitioner - Nephrology · source: CMS PECOS Public Provider Enrollment (2026.04.01)
John Clark, M.D. is a Nephrology Physician provider in Huntsville, AL (NPI 1578631784).
Provider details
- NPI number
- 1578631784
- Entity type
- Individual
- Primary specialty
- Nephrology PhysicianAllopathic & Osteopathic Physicians
- Credential
- M.D.
- Sex
- Male
- Sole proprietor
- Yes
- License
- MD0000040647 (TN)
Specialties & taxonomies
Allopathic & Osteopathic Physicians
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
2,079 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) |
|---|---|---|
| Subsequent Hospital Care With Moderate Levelof Medical Decision Making, If Using Time, at Least 35 Minutes99232 | 575 | $72 |
| Established Patient Office Or Other Outpatient Visit With Low Level OD Decision Making, If Using Time, 20 Minutes Or More99213 | 270 | $75 |
| 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 | 251 | $15 |
| Hemodialysis Procedure With Physician Evaluation90935 | 222 | $65 |
| Home Dialysis Services Per Month (20 Years Or Older)90966 | 140 | $268 |
| Initial Hospital Care With Moderate Level of Medical Decision Making, If Using Time, at Least 75 Minutes |
What this provider prescribes (Medicare Part D)
Top drugs by Medicare Part D claim volume, 2024 · 28 distinct drugs on file.
| Drug | Part D claims (2024) | Beneficiaries |
|---|---|---|
| Paricalcitol | 144 | 41 |
| Amlodipine Besylate | 103 | 29 |
| Losartan Potassium | 97 | 33 |
| Carvedilol | 86 | 27 |
| Hydralazine Hcl | 82 | 24 |
| Sevelamer Carbonate | 77 | 27 |
| Furosemide | 71 | 27 |
| Finerenonebrand: Kerendia |
Transparency — industry payments
Based on CMS Open Payments, 2024; not all care is captured.
$922 across 42 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
- 2006-12-04
- Last updated
- 2026-04-21
- Certified
- 2026-04-21
Frequently asked questions
- What is John Clark's NPI number?
- John Clark's National Provider Identifier (NPI) is 1578631784, a unique 10-digit ID issued by CMS for use in standard healthcare transactions.
- What is John Clark's specialty?
- John Clark is listed in the NPPES registry with a primary specialty of Nephrology Physician (Allopathic & Osteopathic Physicians).
- Where is John Clark located?
- John Clark's practice location on file with NPPES is 2780 Bob Wallace Avenue, Huntsville, AL 35805-4104.
- What is John Clark's phone number?
- The practice phone number listed in the NPPES registry for John Clark is (256) 533-4626.
- Does John Clark accept Medicare?
- John Clark is approved to bill Medicare according to CMS PECOS enrollment data (2026.04.01). Confirm current participation with the provider before scheduling.
- Is John Clark's NPI active?
- Yes — John Clark's NPI (1578631784) is active in the NPPES registry as of the last update on 2026-04-21.
Source: CMS NPPES Data Dissemination (June 2026). NPI Central is not affiliated with CMS. Data is provided as-is from the public registry.