Quick answers
- Does Marcia L. O'Brien accept Medicare assignment?
- Yes. Medicare's clinician data says Marcia L. O'Brien 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 Marcia L. O'Brien see?
- In 2024, CMS data shows 407 Original Medicare patients and 3,857 services for Marcia L. O'Brien. This counts Original Medicare only and measures volume, not quality.
- What is Marcia L. O'Brien's NPI number?
- 1053853176. 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 Marcia L. O'Brien, 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 | 407 |
|---|---|
| Services billed to Medicare | 3,857 |
| Different services or procedures | 34 |
| Participating Medicare provider | Yes |
| Average age of these patients | 76 |
Most frequent services
- Established patient office or other outpatient visit with moderate level of decision making, if using time, 30 minutes or more (99214)402 services
- Ultrasound measurement of bladder capacity after voiding (51798)357 services
- 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's (G2211)294 services
- Automated urinalysis test (81003)268 services
- Manual urinalysis test with examination using microscope, automated (81001)123 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 pressure74%
- Arthritis48%
- Ischemic heart disease38%
- Diabetes28%
- Cancer (breast, colorectal, lung, prostate, endometrial or leukemia/lymphoma)27%
Practice locations
Addresses where Marcia L. O'Brien is enrolled with Medicare (CMS data updated October 2, 2026).
- 12505 Hymeadow Dr, Suite 2cAustin, TX 78750 (512) 238‑0762
- 170 Benney Ln, Suite 202Dripping Springs, TX 78620 (512) 238‑0762
Group practices
Medicare enrollment lists Marcia L. O'Brien as a member of this group (CMS data updated October 2, 2026).
- Sandeep G Mistry MD PA7 clinicians in the group
Specialties
- Nurse Practitionerprimary
Other nurse practitioners in Austin
Clinicians with the same Medicare primary specialty in Austin, TX — not a recommendation.
Other clinicians in Sandeep G Mistry MD PA
Medicare enrollment lists these clinicians in the same group practice — not a recommendation.
Clinician information
| Credential | NP |
|---|---|
| Graduation year | 2016 |
| Gender (as listed) | Female |
| Medicare assignment | Accepts (Medicare-approved amount as full payment) |
| NPI (National Provider Identifier) | 1053853176 |
| 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