Gustavo Day, M.D.
NPI 1538239173 · Internal Medicine Physician · Dallas, TX
Enrolled with Medicare as Practitioner - Internal Medicine · source: CMS PECOS Public Provider Enrollment (2026.04.01)
Gustavo Day, M.D. is a Internal Medicine Physician provider in Dallas, TX (NPI 1538239173).
Provider details
- NPI number
- 1538239173
- Entity type
- Individual
- Primary specialty
- Internal Medicine PhysicianAllopathic & Osteopathic Physicians
- Credential
- M.D.
- Sex
- Male
- Sole proprietor
- Yes
- License
- K1411 (TX)
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
4,024 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) |
|---|---|---|
| Established Patient Office Or Other Outpatient Visit With Moderate Level of Decision Making, If Using Time, 30 Minutes Or More99214 | 705 | $120 |
| Injection of Drug Or Substance Under Skin Or Into Muscle96372 | 596 | $13 |
| Established Patient Office Or Other Outpatient Visit With Low Level OD Decision Making, If Using Time, 20 Minutes Or More99213 | 531 | $85 |
| Insertion of Needle Into Vein for Collection of Blood Sample36415 | 277 | $9 |
| Chronic Care Management Services, First 20 Minutes of Clinical Staff Time Directed By Health Care Professional, Per Calendar Month99490 | 171 | $58 |
| Assessment of Emotional Or Behavioral Problems96127 | 154 |
What this provider prescribes (Medicare Part D)
Top drugs by Medicare Part D claim volume, 2024 · 278 distinct drugs on file.
| Drug | Part D claims (2024) | Beneficiaries |
|---|---|---|
| Hydrocodone/Acetaminophenbrand: Hydrocodone-Acetaminophen | 1,944 | 249 |
| Atorvastatin Calcium | 1,756 | 566 |
| Losartan Potassium | 1,361 | 437 |
| Alprazolam | 1,033 | 168 |
| Gabapentin | 860 | 241 |
| Hydralazine Hcl | 804 | 245 |
| Levothyroxine Sodium |
Transparency — industry payments
Based on CMS Open Payments, 2024; not all care is captured.
$4,730 across 247 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
- 2006-11-09
- Last updated
- 2026-05-18
- Certified
- 2026-05-18
Frequently asked questions
- What is Gustavo Day's NPI number?
- Gustavo Day's National Provider Identifier (NPI) is 1538239173, a unique 10-digit ID issued by CMS for use in standard healthcare transactions.
- What is Gustavo Day's specialty?
- Gustavo Day is listed in the NPPES registry with a primary specialty of Internal Medicine Physician (Allopathic & Osteopathic Physicians).
- Where is Gustavo Day located?
- Gustavo Day's practice location on file with NPPES is 7777 Forest Ln, Dallas, TX 75230-2505.
- What is Gustavo Day's phone number?
- The practice phone number listed in the NPPES registry for Gustavo Day is (972) 566-6764.
- Does Gustavo Day accept Medicare?
- Gustavo Day is approved to bill Medicare according to CMS PECOS enrollment data (2026.04.01). Confirm current participation with the provider before scheduling.
- Is Gustavo Day's NPI active?
- Yes — Gustavo Day's NPI (1538239173) is active in the NPPES registry as of the last update on 2026-05-18.
Source: CMS NPPES Data Dissemination (June 2026). NPI Central is not affiliated with CMS. Data is provided as-is from the public registry.