Quick answers
- Does Mark C. Glass- Royal accept Medicare assignment?
- Yes. Medicare's clinician data says Mark C. Glass- Royal accepts Medicare assignment (the Medicare-approved amount as full payment for covered services), as of October 2, 2026. Ask the office to confirm before your visit.
- How many Medicare patients does Mark C. Glass- Royal see?
- In 2024, CMS data shows 1,846 Original Medicare patients and 12,060 services for Mark C. Glass- Royal. This counts Original Medicare only and measures volume, not quality.
- What is Mark C. Glass- Royal's NPI number?
- 1255361887. The NPI (National Provider Identifier) is the clinician's permanent federal ID; you can look it up in the official NPI Registry.
Medicare activity in 2024
Official CMS public-use data for Mark C. Glass- Royal, data year 2024 (released May 21, 2026). It covers Original Medicare (fee-for-service) patients only, not Medicare Advantage or other insurance. It shows volume, not quality or outcomes. CMS hides any count of 10 or fewer patients.
| Original Medicare patients | 1,846 |
|---|---|
| Services billed to Medicare | 12,060 |
| Different services or procedures | 110 |
| Participating Medicare provider | Yes |
| Average age of these patients | 74 |
Most frequent services
- Low osmolar contrast material, 300-399 mg/ml iodine concentration, per ml (Q9967)6,853 services
- Injection, gadoterate meglumine, 0.1 ml (A9575)2,780 services
- Dxa bone density measurement of hip, pelvis, spine (77080)485 services
- Ultrasound scan of head and neck soft tissue (76536)206 services
- Ultrasound scan of uterus, ovaries, tubes, cervix and pelvic area through vagina (76830)155 services
Chronic conditions among these patients
Share of this clinician’s Original Medicare patients with each condition, as published by CMS (it describes the patients, not the care given).
- High cholesterol75%
- High blood pressure54%
- Arthritis50%
- Osteoporosis28%
- Ischemic heart disease18%
- Diabetes17%
Practice locations
Addresses where Mark C. Glass- Royal is enrolled with Medicare (CMS data updated October 2, 2026).
- 21351 Ridgetop Cir, Suite 100Sterling, VA 20166 (571) 434‑0140
- 3022 Williams Dr, Suite 200Fairfax, VA 22031 (703) 698‑8800
Group practices
Medicare enrollment lists Mark C. Glass- Royal as a member of this group (CMS data updated October 2, 2026).
- Washington Radiology Assoc PLLC36 clinicians in the group
Specialties
- Diagnostic Radiologyprimary
Other radiologists in Sterling
Clinicians with the same Medicare primary specialty in Sterling, VA — not a recommendation.
Other clinicians in Washington Radiology Assoc PLLC
Medicare enrollment lists these clinicians in the same group practice — not a recommendation.
Clinician information
| Credential | MD |
|---|---|
| Medical school | George Washington University School Of Medicine |
| Graduation year | 1984 (42 years since medical school) |
| Gender (as listed) | Male |
| Medicare assignment | Accepts (Medicare-approved amount as full payment) |
| NPI (National Provider Identifier) | 1255361887 |
| Corrections | Report an error or suggest an update → |
Most corrections must be made at the source: clinicians update their NPI Registry record (NPPES) and their Medicare enrollment (PECOS); this page follows the next data release.
Sources
- National Downloadable File (Doctors and Clinicians) — CMS, data updated October 2, 2026, retrieved October 29, 2026
- Medicare Physician & Other Practitioners - by Provider — CMS, data year 2024, released May 21, 2026; Medicare Physician & Other Practitioners - by Provider and Service
- NPI Registry — U.S. Department of Health and Human Services (NPPES), the clinician’s official record
- Medicare Care Compare — official Medicare tool to look up clinicians