Mark Day, DO
NPI 1164436994 · Family Medicine Physician · Las Vegas, NV
Enrolled with Medicare as Practitioner - Family Practice · source: CMS PECOS Public Provider Enrollment (2026.04.01)
Mark Day, DO is a Family Medicine Physician provider in Las Vegas, NV (NPI 1164436994).
Provider details
- NPI number
- 1164436994
- Entity type
- Individual
- Primary specialty
- Family Medicine PhysicianAllopathic & Osteopathic Physicians
- Credential
- DO
- Sex
- Male
- Sole proprietor
- No
- License
- 656 (NV)
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
2 documented practice locations
- Medicare service volume (vs. specialty peers)25% of score
718 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 Low Level OD Decision Making, If Using Time, 20 Minutes Or More99213 | 619 | $88 |
| Administration of Influenza Virus VaccineG0008 | 20 | $32 |
| Established Patient Office Or Other Outpatient Visit With Moderate Level of Decision Making, If Using Time, 30 Minutes Or More99214 | 19 | $125 |
| Routine Electrocardiogram (ecg) Using at Least 12 Leads With Interpretation and Report93000 | 17 | $14 |
| Removal of Deep Lymph Nodes of Neck38542 | 15 | $43 |
| Removal Or Exploration of Parathyroid Glands60500 | 14 |
What this provider prescribes (Medicare Part D)
Top drugs by Medicare Part D claim volume, 2024 · 95 distinct drugs on file.
| Drug | Part D claims (2024) | Beneficiaries |
|---|---|---|
| Atorvastatin Calcium | 838 | 258 |
| Amlodipine Besylate | 432 | 136 |
| Levothyroxine Sodium | 397 | 113 |
| Lisinopril | 340 | 103 |
| Rosuvastatin Calcium | 314 | 108 |
| Metformin Hcl | 301 | 95 |
| Losartan Potassium |
Transparency — industry payments
Based on CMS Open Payments, 2024; not all care is captured.
$124 across 1 record (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
Additional practice locations (1)
- 56 N Pecos RdSte aHenderson, NV 89074-0698Phone: (702) 456-9100Fax: (702) 434-7354
Registry dates
- Enumerated
- 2006-07-28
- Last updated
- 2025-11-06
- Certified
- 2025-11-06
Frequently asked questions
- What is Mark Day's NPI number?
- Mark Day's National Provider Identifier (NPI) is 1164436994, a unique 10-digit ID issued by CMS for use in standard healthcare transactions.
- What is Mark Day's specialty?
- Mark Day is listed in the NPPES registry with a primary specialty of Family Medicine Physician (Allopathic & Osteopathic Physicians).
- Where is Mark Day located?
- Mark Day's practice location on file with NPPES is 1655 E Cactus Ave Ste 400, Las Vegas, NV 89183-7723.
- What is Mark Day's phone number?
- The practice phone number listed in the NPPES registry for Mark Day is (702) 724-8777.
- Does Mark Day accept Medicare?
- Mark Day is approved to bill Medicare according to CMS PECOS enrollment data (2026.04.01). Confirm current participation with the provider before scheduling.
- Is Mark Day's NPI active?
- Yes — Mark Day's NPI (1164436994) is active in the NPPES registry as of the last update on 2025-11-06.
Source: CMS NPPES Data Dissemination (June 2026). NPI Central is not affiliated with CMS. Data is provided as-is from the public registry.