Tammy Sievers, MD
NPI 1619004694 · Rheumatology Physician · Ventura, CA
Enrolled with Medicare as Practitioner - Rheumatology · source: CMS PECOS Public Provider Enrollment (2026.04.01)
Tammy Sievers, MD is a Rheumatology Physician provider in Ventura, CA (NPI 1619004694).
Provider details
- NPI number
- 1619004694
- Entity type
- Individual
- Primary specialty
- Rheumatology PhysicianAllopathic & Osteopathic Physicians
- Credential
- MD
- Sex
- Female
- Sole proprietor
- No
- License
- A110176 (CA)
Specialties & taxonomies
Allopathic & Osteopathic Physicians
Profile Score
A profile completeness & documented-activity index — NOT a quality, outcomes, or patient-satisfaction rating.
- Registry tenure25% of score
19 yrs in NPPES registry
- Profile completeness25% of score
100% of core fields populated
- Practice footprint15% of score
2 documented practice locations
- Medicare service volume (vs. specialty peers)25% of score
1,034 Medicare services, 2024 (ranked within specialty)
- Open Payments transparency10% of score
Has Open Payments disclosures (2024)
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 .
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) |
|---|---|---|
| Established Patient Office Or Other Outpatient Visit With Moderate Level of Decision Making, If Using Time, 30 Minutes Or More99214 | 777 | $102 |
| Established Patient Office Or Other Outpatient Visit With Low Level OD Decision Making, If Using Time, 20 Minutes Or More99213 | 113 | $69 |
| New Patient Office Or Other Outpatient Visit With Moderate Level of Medical Decision Making, If Using Time, 45 Minutes Or More99204 | 45 | $140 |
| Established Patient Office Or Other Outpatient Visit With High Level of Medical Decision Making, If Using Time, 40 Minutes Or More99215 | 38 | $151 |
| New Patient Office Or Other Outpatient Visit With a High Level of Medical Decision Making, If Using Time, 60 Minutes Or More99205 | 24 | $190 |
| Aspiration And/Or Injection of Fluid From Large Joint |
What this provider prescribes (Medicare Part D)
Top drugs by Medicare Part D claim volume, 2024 · 59 distinct drugs on file.
| Drug | Part D claims (2024) | Beneficiaries |
|---|---|---|
| Prednisone | 344 | 105 |
| Methotrexate Sodiumbrand: Methotrexate | 283 | 81 |
| Hydroxychloroquine Sulfate | 177 | 54 |
| Sulfasalazinebrand: Sulfasalazine Dr | 170 | 54 |
| Celecoxib | 160 | 60 |
| Tramadol Hcl | 148 | 30 |
| Leflunomide | 121 | 37 |
Transparency — industry payments
Based on CMS Open Payments, 2024; not all care is captured.
$555 across 26 records (Open Payments 2024)
Open Payments discloses payments and transfers of value (meals, travel, consulting, research, royalties) from drug and device makers to providers. This is a transparency signal, not a verdict — such payments are legal and common, and their presence is neither an endorsement nor a criticism. Source: CMS Open Payments, program year 2024.
Practice location
Mailing address
Additional practice locations (1)
- 5855 Olivas Park DrVentura, CA 93003-7672Phone: (805) 667-2801Fax: (805) 667-2865
Registry dates
- Enumerated
- 2007-02-27
- Last updated
- 2021-03-08
- Certified
- 2021-03-08
Frequently asked questions
- What is Tammy Sievers's NPI number?
- Tammy Sievers's National Provider Identifier (NPI) is 1619004694, a unique 10-digit ID issued by CMS for use in standard healthcare transactions.
- What is Tammy Sievers's specialty?
- Tammy Sievers is listed in the NPPES registry with a primary specialty of Rheumatology Physician (Allopathic & Osteopathic Physicians).
- Where is Tammy Sievers located?
- Tammy Sievers's practice location on file with NPPES is 120 N Ashwood Ave, Ventura, CA 93003-1810.
- What is Tammy Sievers's phone number?
- The practice phone number listed in the NPPES registry for Tammy Sievers is (805) 658-5800.
- Does Tammy Sievers accept Medicare?
- Tammy Sievers is approved to bill Medicare according to CMS PECOS enrollment data (2026.04.01). Confirm current participation with the provider before scheduling.
- Is Tammy Sievers's NPI active?
- Yes — Tammy Sievers's NPI (1619004694) is active in the NPPES registry as of the last update on 2021-03-08.
Source: CMS NPPES Data Dissemination (June 2026). NPI Central is not affiliated with CMS. Data is provided as-is from the public registry.