Quick answers
- Does Siobhan L. Calhoun accept Medicare assignment?
- Yes. Medicare's clinician data says Siobhan L. Calhoun 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 Siobhan L. Calhoun see?
- In 2024, CMS data shows 62 Original Medicare patients and 148 services for Siobhan L. Calhoun. This counts Original Medicare only and measures volume, not quality.
- What is Siobhan L. Calhoun's NPI number?
- 1396726295. 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 Siobhan L. Calhoun, 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 | 62 |
|---|---|
| Services billed to Medicare | 148 |
| Different services or procedures | 15 |
| Participating Medicare provider | Yes |
| Average age of these patients | 72 |
Most frequent services
- Cervical or vaginal cancer screening; pelvic and clinical breast examination (G0101)31 services
- Established patient office or other outpatient visit with low level od decision making, if using time, 20 minutes or more (99213)27 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%
- Arthritis47%
- Diabetes35%
- Chronic kidney disease27%
- Osteoporosis26%
Hospitals where Siobhan L. Calhoun works
Medicare's Facility Affiliation Data lists Siobhan L. Calhoun at these hospitals (updated October 2, 2026). Each hospital page shows its address, phone, emergency services, Medicare rating and all its clinicians. Star rating and emergency services: Hospital General Information (CMS), data updated October 26, 2026.
- Washington HospitalFremont, CA · Acute Care Hospital · Medicare rating: 2 of 5 stars · Emergency services: listed by Medicare · CCN 050195
Practice locations
Addresses where Siobhan L. Calhoun is enrolled with Medicare (CMS data updated October 2, 2026).
- 2299 Mowry AveFremont, CA 94538
- 39500 Fremont Blvd, Suite 100Fremont, CA 94538 (510) 687‑9510
Group practices
Medicare enrollment lists Siobhan L. Calhoun as a member of this group (CMS data updated October 2, 2026).
- Washington Township Medical Foundation117 clinicians in the group
Specialties
- Obstetrics/Gynecologyprimary
Other OB-GYNs in Fremont
Clinicians with the same Medicare primary specialty in Fremont, CA — not a recommendation.
Other clinicians in Washington Township Medical Foundation
Medicare enrollment lists these clinicians in the same group practice — not a recommendation.
Clinician information
| Credential | MD |
|---|---|
| Medical school | Eastern Virginia Medical School |
| Graduation year | 1995 (31 years since medical school) |
| Gender (as listed) | Female |
| Medicare assignment | Accepts (Medicare-approved amount as full payment) |
| NPI (National Provider Identifier) | 1396726295 |
| 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
- Facility Affiliation Data — Centers for Medicare & Medicaid Services (CMS), data updated October 2, 2026, retrieved October 29, 2026
- Hospital General Information — CMS, data updated October 26, 2026, retrieved November 13, 2026
- 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