Karen Mrejen, MD
NPI 1902999212 · Pulmonary Disease Physician · Rockville Centre, NY
Enrolled with Medicare as Practitioner - Pulmonary Disease · source: CMS PECOS Public Provider Enrollment (2026.04.01)
Karen Mrejen, MD is a Pulmonary Disease Physician provider in Rockville Centre, NY (NPI 1902999212).
Provider details
- NPI number
- 1902999212
- Entity type
- Individual
- Primary specialty
- Pulmonary Disease PhysicianAllopathic & Osteopathic Physicians
- Credential
- MD
- Sex
- Female
- Sole proprietor
- No
- License
- 224857 (NY)
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
2,165 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) |
|---|---|---|
| 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 | 610 | $19 |
| Established Patient Office Or Other Outpatient Visit With Low Level OD Decision Making, If Using Time, 20 Minutes Or More99213 | 388 | $105 |
| Established Patient Office Or Other Outpatient Visit With Moderate Level of Decision Making, If Using Time, 30 Minutes Or More99214 | 187 | $147 |
| Test to Measure Expiratory Airflow and Volume94010 | 95 | $32 |
| New Patient Office Or Other Outpatient Visit With a High Level of Medical Decision Making, If Using Time, 60 Minutes Or More99205 | 95 | $254 |
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 |
|---|---|---|
| Albuterol Sulfatebrand: Albuterol Sulfate Hfa | 538 | 205 |
| Fluticasone/Umeclidin/Vilanterbrand: Trelegy Ellipta | 286 | 85 |
| Fluticasone/Vilanterolbrand: Breo Ellipta | 246 | 67 |
| Azithromycin | 213 | 86 |
| Prednisone | 186 | 80 |
| Azelastine Hcl | 143 | 67 |
| Fluticasone Propion/Salmeterolbrand: Fluticasone-Salmeterol |
Practice location
Mailing address
Registry dates
- Enumerated
- 2006-10-02
- Last updated
- 2013-11-14
Frequently asked questions
- What is Karen Mrejen's NPI number?
- Karen Mrejen's National Provider Identifier (NPI) is 1902999212, a unique 10-digit ID issued by CMS for use in standard healthcare transactions.
- What is Karen Mrejen's specialty?
- Karen Mrejen is listed in the NPPES registry with a primary specialty of Pulmonary Disease Physician (Allopathic & Osteopathic Physicians).
- Where is Karen Mrejen located?
- Karen Mrejen's practice location on file with NPPES is 200 N Village Ave, Rockville Centre, NY 11570-2341.
- What is Karen Mrejen's phone number?
- The practice phone number listed in the NPPES registry for Karen Mrejen is (516) 536-8151.
- Does Karen Mrejen accept Medicare?
- Karen Mrejen is approved to bill Medicare according to CMS PECOS enrollment data (2026.04.01). Confirm current participation with the provider before scheduling.
- Is Karen Mrejen's NPI active?
- Yes — Karen Mrejen's NPI (1902999212) is active in the NPPES registry as of the last update on 2013-11-14.
Source: CMS NPPES Data Dissemination (June 2026). NPI Central is not affiliated with CMS. Data is provided as-is from the public registry.