Medicare Enrolled
Dr. Robert Zajac, MD
Infectious Disease · San Antonio, TX
Practice pattern: Mixed Practice
— Diverse clinical practice across multiple procedure types
Very High
DATA COVERAGE
Data in 4 of 4 federal sources
Measures public federal data availability — not provider quality
Informational, not a quality rating.
This page presents federal public records about Dr. Zajac from CMS (NPPES, Open Payments, Medicare Provider Utilization, PECOS). It is not medical advice, an endorsement, or a judgment of clinical quality. Always consult the provider directly and a licensed clinician for medical decisions. Read methodology →
Are you Dr. Zajac?
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What this data tells you about Dr. Zajac
Dr. Robert Zajac is an infectious disease specialist in San Antonio, TX, with 20 years of NPI registration. Based on federal Medicare data, Dr. Zajac performed 60,431 Medicare services in 2023. These records do not provide a deduplicated patient total.
Between the years covered by Open Payments, Dr. Zajac received a total of $12,550 from 41 pharmaceutical and/or device companies across 571 payment records. A record can group multiple payments. These transfers are publicly reported through CMS Open Payments. Disclosure alone does not establish their effect on care. A reliable breakdown by payment category is not available in this snapshot. Patients may wish to discuss these relationships with their provider.
The Data Coverage level for Dr. Zajac is Very High — reflecting how much public federal data is available about this provider. Patients are encouraged to use this data as one of several factors when choosing a healthcare provider.
✓ 20 years of NPI registration
▲ Top 2% volume in TX
$12,550 industry payments
Medicare Practice Summary — 2023
Medicare Utilization ↗60,431
Medicare services
Top 2% in TX for infectious disease
Not available
Unique patients (not deduplicated)
$52
Avg. Medicare payment
Medicare patients only (65+ / disabled) · How to read this →
Top procedures by volume
Ranked by number of services performed for Medicare patients. Avg. submitted charge is what the provider billed; avg. Medicare payment is what CMS paid.
| Procedure | Volume | Avg. paid | Avg. submitted |
|---|---|---|---|
| Injection, immune globulin, (gamunex-c/gammaked), non-lyophilized (e.g., liquid), 500 mg | 38,530 | $39 | $297 |
| Injection, immune globulin (bivigam), 500 mg | 15,960 | $56 | $244 |
| Additional hour of intravenous infusion This code represents each additional hour of intravenous infusion beyond the initial hour for therapy, prevention, or diagnosis. |
1,960 | $16 | $67 |
| Hospital follow-up visit, high complexity Subsequent hospital inpatient or observation care for an existing patient involving high-level medical decision making, with at least 50 minutes total time on the date of the encounter. |
737 | $91 | $204 |
| Hospital follow-up visit, moderate complexity Follow-up hospital visit for an existing patient involving moderate medical decision making. The visit requires at least 35 minutes of time spent on the date of service. |
657 | $61 | $142 |
| Intravenous infusion, 1 hour or less Administration of medication or fluid directly into a vein for therapeutic, preventive, or diagnostic purposes. The procedure lasts one hour or less. |
639 | $49 | $215 |
| Intravenous immune globulin injection, 500 mg An injection of immune globulin administered into a vein to provide antibodies. The dose specified is 500 mg of non-lyophilized (liquid) immune globulin. |
593 | $885 | $5,599 |
| Intravenous injection of additional new drug or substance Administration of an additional new medication or substance directly into a vein. |
362 | $12 | $51 |
| Ketorolac injection, per 15 mg An injection of ketorolac tromethamine, a nonsteroidal anti-inflammatory drug, administered in doses measured per 15 mg. |
334 | $0 | $1 |
| Initial hospital admission, high complexity Initial hospital inpatient or observation care for a new patient involving high-level medical decision making, with at least 75 minutes total time on the date of the encounter. |
271 | $132 | $397 |
| Office visit, established patient, complex (40-54 min) An office or outpatient visit for an existing patient lasting between 40 and 54 minutes. This level of service is determined by the total time spent on the date of the encounter. |
130 | $122 | $280 |
| Initial hospital admission, moderate complexity Initial hospital inpatient or observation care for a new patient involving moderate-level medical decision making, with at least 55 minutes total time on the date of the encounter. |
66 | $100 | $268 |
| Hospital follow-up visit, low complexity Follow-up hospital visit for an established patient with straightforward or low-level medical decision making. The visit requires at least 25 minutes of time spent on the day of service. |
43 | $39 | $76 |
| Office visit, established patient (30-39 min) A follow-up office visit for an existing patient lasting between 30 and 39 minutes. The visit involves medical evaluation and management of the patient's condition. |
41 | $93 | $214 |
| Home health plan of care certification Certification by a physician or allowed practitioner for Medicare-covered home health services under a home health plan of care. This includes contacting the home health agency and reviewing reports of patient status required by physicians. |
40 | $40 | $103 |
| Prolonged office E/M service, first 15 minutes This code is used for additional time spent by a physician beyond the maximum required time of a primary office or outpatient evaluation and management service. It is billed in 15-minute increments based on total time spent on the date of the primary service. |
29 | $24 | $150 |
| Home health agency supervision, complex multidisciplinary care Supervision by a physician or allowed practitioner for a patient receiving Medicare-covered services from a participating home health agency. This involves complex and multidisciplinary care modalities, with the patient not present during the supervision. |
22 | $79 | $209 |
| New patient office visit (45-59 min) An initial office visit for a new patient lasting between 45 and 59 minutes. This code covers the total time spent by the physician or qualified healthcare professional on the date of the encounter. |
17 | $103 | $318 |
How to read this data: This reflects Medicare patients only (typically 65+). Payment amounts are what Medicare paid the provider, not your out-of-pocket cost. These counts do not measure clinical quality or years of experience.
4.3% high complexity
92.3% medium
3.4% routine
Industry Payment Transparency
Open Payments through 2024 ↗$12,550
Total received (2018-2024)
Avg $1,793/year across 7 years
Top 12% in TX for infectious disease
A higher payment rank reflects disclosed industry relationships (consulting, research, speaking) common among subspecialists — not wrongdoing.
41
Companies
571
Payment records
Payments are publicly reported; disclosure does not establish legality · Not evidence of wrongdoing · How to interpret →
Payment categories are unavailable while the source breakdown is being rebuilt. Company and year totals do not identify how much belongs to each category.
Payment trend by year
Annual totals from pharmaceutical and medical device companies.
2024
$487
2023
$616
2022
$826
2021
$1,436
2020
$2,844
2019
$3,041
2018
$3,299
Payments by company (2024)
ABBVIE INC.
$154
ViiV Healthcare Company
$102
AIMMUNE THERAPEUTICS, INC.
$53
Grifols USA, LLC
$46
Gilead Sciences, Inc.
$39
Pharming Healthcare, Inc.
$26
Shionogi Inc
$24
Paratek Pharmaceuticals, Inc.
$23
Octapharma USA, Inc.
$20
Top 3 companies account for 63.4% of 2024 payments
All-time payments by company (2018-2024) ›
CIPLA USA INC.
$2,041
Gilead Sciences, Inc.
$1,969
ViiV Healthcare Company
$1,947
Merck Sharp & Dohme Corporation
$1,536
Janssen Biotech, Inc.
$714
Allergan Inc.
$413
Grifols USA, LLC
$397
ABBVIE INC.
$379
Melinta Therapeutics, Inc.
$372
Theratechnologies Inc.
$298
Allergan, Inc.
$279
Paratek Pharmaceuticals, Inc.
$216
Cumberland Pharmaceuticals, Inc.
$209
AbbVie Inc.
$184
Insmed, Inc.
$164
Octapharma USA, Inc.
$129
Theravance Biopharma, Inc.
$118
EMD Serono, Inc.
$101
Ferring Pharmaceuticals Inc.
$99
Shionogi Inc
$95
Aytu BioScience, Inc
$93
PFIZER INC.
$86
Takeda Pharmaceuticals U.S.A., Inc.
$82
CSL Behring
$77
Napo Pharmaceuticals Inc
$66
Vyera Pharmaceuticals, LLC
$61
Mayne Pharma Inc.
$58
AIMMUNE THERAPEUTICS, INC.
$53
La Jolla Pharmaceutical Company
$43
ADMA BioManufacturing LLC
$42
TETRAPHASE PHARMACEUTICALS, INC.
$33
INSYS Therapeutics Inc
$32
Shire North American Group Inc
$28
Pharming Healthcare, Inc.
$26
Smith+Nephew, Inc.
$20
VYERA PHARMACEUTICALS, LLC
$18
Antares Pharma, Inc.
$16
Merck Sharp & Dohme LLC
$15
Aytu Bioscience, Inc
$14
Salix Pharmaceuticals, a division of Bausch Health US, LLC
$13
Melinta Therapeutics, LLC
$11
Top 3 companies account for 47.5% of all-time payments
Associated products mentioned in payments ›
APRETUDE · AVYCAZ · Arikayce · Baxdela · Biktarvy · CABENUVA · CHANTIX · CUTAQUIG · CUVITRU · DALVANCE · DIFICID · DORYX · DOVATO · Daraprim · Daraprim 30 Tablet in 1 Bottle · Daraprim Tablet 25mg · Descovy · EGRIFTA · Fetroja · GRAFIX PL · Gamunex-C · Hizentra · ISENTRESS · JULUCA · Mytesi · NUZYRA · Natesto · OCTAGAM · OCTAGAM IMMUNE GLOBULIN (HUMAN) · Orbactiv · PANZYGA · PIFELTRO · PREZCOBIX · PREZISTA · REBYOTA · RUKOBIA · SEROSTIM · SYMTUZA · SYNDROS · Serostim · Symtuza · TEFLARO · TIVICAY · TRIUMEQ · TROGARZO · VIBATIV · VOWST · VPRIV · Vabomere · Veklury · Vemlidy · Vibativ · XARELTO · XERAVA · XIFAXAN · XYOSTED · Xembify · Xerava · ZEMDRI (PLAZOMICIN) · ZERBAXA · ZINPLAVA
Should you be concerned? Industry payments are disclosed through CMS Open Payments. Disclosure alone does not establish their purpose, legality, or effect on care. What matters is whether a recommended drug or device appears in your doctor's payment records. If so, consider asking your doctor about it. How to interpret this data →
Geographic Context
Infectious diseases in nearby ZIP areas
55
County median income
$70,571
Nearest hospital to ZIP centroid (approximate)
SOUTH TEXAS SPINE AND SURGICAL HOSPITAL
0.0 mi
0.0 mi
Data Sources
| Provider Registry | ✓ NPPES | NPPES snapshot; verify current record |
| Medicare Enrollment | ✓ PECOS | PECOS snapshot |
| Practice Data | ✓ Medicare Util. | Annual (CY lag) |
| Industry Payments | ✓ Open Payments | CY 2024 |
| Disciplinary History | — Not included | N/A |
This provider has data in 4 of 4 available federal datasets, with a Data Coverage level of Very High. This reflects how much public data is available about a provider. How we calculate this →
Summary
Dr. Zajac is a mixed practice specialist, with above-average Medicare volume (top 2% in TX), with 20 years of NPI registration.
This summary is auto-generated from federal data, describing data availability and patterns. Read our methodology →
Frequently Asked Questions
Is Dr. Zajac experienced with injection, immune globulin, (gamunex-c/gammaked), non-lyophilized (e.g., liquid), 500 mg?
Based on Medicare claims data, Dr. Zajac performed 38,530 injection, immune globulin, (gamunex-c/gammaked), non-lyophilized (e.g., liquid), 500 mg services. These records cover Medicare fee-for-service activity, including eligible younger beneficiaries; they do not measure total practice volume or clinical quality.
Does Dr. Zajac receive payments from pharmaceutical companies?
Yes. Dr. Zajac received a total of $12,550 from 41 companies across 571 payment records. A record can group multiple payments. These transfers are publicly disclosed through CMS Open Payments. Disclosure alone does not establish their legality or effect on care. Patients may wish to ask their doctor about these relationships, especially if a recommended drug or device appears in the payment records.
How do Dr. Zajac's costs compare to other infectious diseases in San Antonio?
Dr. Zajac's average Medicare payment per service is $52. Note that these figures represent what Medicare pays, not your out-of-pocket cost, which depends on your specific insurance plan and deductible. Procedure-level data above shows both what was submitted and what Medicare paid for each service type.
What does Data Coverage mean?
Data Coverage (currently Very High for Dr. Zajac) measures how much public federal data is available about a provider. It is not a quality rating. A "Very High" or "High" level means the provider has data across multiple federal sources (NPPES, PECOS, Medicare Utilization, Open Payments), indicating the presence of registry, enrollment, activity or payment records, not verified experience or clinical quality. A "Low" or "Moderate" level may simply mean the provider is newer, does not see Medicare patients, or has not received any industry payments — none of which are inherently negative. Read our full methodology →
Is this data up to date?
Source publication dates and the snapshots loaded on this site can differ. Rebuilding a page does not refresh its source records. Check the Medicare reporting year and the payment interval shown above; consult the linked official sources for newer releases and current registry details. See our data freshness policy →
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About this page
This page combines public CMS records with calculated summaries and explanatory procedure labels. These transformations are not verbatim federal records. Sources: NPPES ↗, Open Payments ↗, Medicare Provider Utilization ↗, and PECOS. Publication is mandated by the Physician Payments Sunshine Act (§6002 ACA, 42 U.S.C. §1320a-7h) and the Freedom of Information Act.
This page is not medical advice, an endorsement, a recommendation, or a quality rating. Data Coverage reflects data completeness — how much federal information exists for this provider — not clinical performance, patient outcomes, or quality of care. Always verify information directly with the provider and consult a licensed clinician before making medical decisions.
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