Mark Grijnsztein, M.D.
NPI 1164580866 · Allergy & Immunology Physician · Elk Grove, CA
Enrolled with Medicare as Practitioner - Allergy/Immunology · source: CMS PECOS Public Provider Enrollment (2026.04.01)
Provider details
- NPI number
- 1164580866
- Entity type
- Individual
- Primary specialty
- Allergy & Immunology PhysicianAllopathic & Osteopathic Physicians
- Credential
- M.D.
- Sex
- Male
- Sole proprietor
- No
- License
- A96813 (CA)
Specialties & taxonomies
Allopathic & Osteopathic Physicians
Profile Score
A profile completeness & documented-activity index — NOT a quality, outcomes, or patient-satisfaction rating.
- Registry tenure28% of score
19 yrs in NPPES registry
- Profile completeness28% of score
100% of core fields populated
- Practice footprint17% of score
1 documented practice location
- Medicare service volume (vs. specialty peers)28% of score
2,502 Medicare services, 2024 (ranked within specialty)
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 methodology.
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) |
|---|---|---|
| Test for Allergy Using Allergenic Extract95004 | 1,494 | $4 |
| Professional Service for Preparation and Provision of 1 Or More Antigens95165 | 550 | $16 |
| Professional Service for Multiple Injections of Allergen95117 | 240 | $14 |
| Established Patient Office Or Other Outpatient Visit With Low Level OD Decision Making, If Using Time, 20 Minutes Or More99213 | 85 | $94 |
| New Patient Office Or Other Outpatient Visit With Low Level of Medical Decision Making, If Using Time, 30 Minutes Or More99203 | 38 | $118 |
| New Patient Office Or Other Outpatient Visit With Moderate Level of Medical Decision Making, If Using Time, 45 Minutes Or More99204 | 37 |
What this provider prescribes (Medicare Part D)
Top drugs by Medicare Part D claim volume, 2024 · 22 distinct drugs on file.
| Drug | Part D claims (2024) | Beneficiaries |
|---|---|---|
| Ipratropium Bromide | 126 | 41 |
| Fluticasone/Umeclidin/Vilanterbrand: Trelegy Ellipta | 70 | 15 |
| Dupilumabbrand: Dupixent Syringe | 67 | — |
| Azelastine Hcl | 51 | 22 |
| Fluticasone Propionate | 46 | 22 |
| Albuterol Sulfatebrand: Albuterol Sulfate Hfa | 43 | 23 |
| Montelukast Sodium |
Practice location
Mailing address
Registry dates
- Enumerated
- 2006-12-05
- Last updated
- 2015-07-29
Source: CMS NPPES Data Dissemination (June 2026). NPI Central is not affiliated with CMS. Data is provided as-is from the public registry.