Robert Zajac, MD
NPI 1013907963 · Infectious Disease Physician · San Antonio, TX
Enrolled with Medicare as Practitioner - Infectious Disease · source: CMS PECOS Public Provider Enrollment (2026.04.01)
Robert Zajac, MD is a Infectious Disease Physician provider in San Antonio, TX (NPI 1013907963).
Provider details
- NPI number
- 1013907963
- Entity type
- Individual
- Primary specialty
- Infectious Disease PhysicianAllopathic & Osteopathic Physicians
- Credential
- MD
- Sex
- Male
- Sole proprietor
- No
- License
- H3973 (TX)
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
20 yrs in NPPES registry
- Profile completeness25% of score
100% of core fields populated
- Practice footprint15% of score
1 documented practice location
- Medicare service volume (vs. specialty peers)25% of score
1,512 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) |
|---|---|---|
| Subsequent Hospital Care With Moderate Levelof Medical Decision Making, If Using Time, at Least 50 Minutes99233 | 471 | $113 |
| Subsequent Hospital Care With Moderate Levelof Medical Decision Making, If Using Time, at Least 35 Minutes99232 | 384 | $74 |
| Initial Hospital Care With Moderate Level of Medical Decision Making, If Using Time, at Least 75 Minutes99223 | 226 | $165 |
| Established Patient Office Or Other Outpatient Visit With Moderate Level of Decision Making, If Using Time, 30 Minutes Or More99214 | 111 | $112 |
| Infusion Into a Vein for Therapy, Prevention, Or Diagnosis, Each Additional Hour96366 | 97 | $19 |
| Established Patient Office Or Other Outpatient Visit With High Level of Medical Decision Making, If Using Time, 40 Minutes Or More |
What this provider prescribes (Medicare Part D)
Top drugs by Medicare Part D claim volume, 2024 · 43 distinct drugs on file.
| Drug | Part D claims (2024) | Beneficiaries |
|---|---|---|
| Doxycycline Hyclate | 437 | 150 |
| Cefdinir | 162 | 64 |
| Bictegrav/Emtricit/Tenofov Alabrand: Biktarvy | 147 | 21 |
| Cefadroxil | 138 | 54 |
| Daptomycin | 81 | 21 |
| Levofloxacin | 80 | 50 |
| Amoxicillin | 58 | 22 |
| Memantine Hcl | 56 | 16 |
Transparency — industry payments
Based on CMS Open Payments, 2024; not all care is captured.
$487 across 24 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
Registry dates
- Enumerated
- 2005-10-24
- Last updated
- 2024-08-08
- Certified
- 2024-08-08
Frequently asked questions
- What is Robert Zajac's NPI number?
- Robert Zajac's National Provider Identifier (NPI) is 1013907963, a unique 10-digit ID issued by CMS for use in standard healthcare transactions.
- What is Robert Zajac's specialty?
- Robert Zajac is listed in the NPPES registry with a primary specialty of Infectious Disease Physician (Allopathic & Osteopathic Physicians).
- Where is Robert Zajac located?
- Robert Zajac's practice location on file with NPPES is 150 E Sonterra Blvd, San Antonio, TX 78258-4098.
- What is Robert Zajac's phone number?
- The practice phone number listed in the NPPES registry for Robert Zajac is (210) 481-2800.
- Does Robert Zajac accept Medicare?
- Robert Zajac is approved to bill Medicare according to CMS PECOS enrollment data (2026.04.01). Confirm current participation with the provider before scheduling.
- Is Robert Zajac's NPI active?
- Yes — Robert Zajac's NPI (1013907963) is active in the NPPES registry as of the last update on 2024-08-08.
Source: CMS NPPES Data Dissemination (June 2026). NPI Central is not affiliated with CMS. Data is provided as-is from the public registry.