Medicare Enrolled
Dr. Jacek Zajac, M.D.
Endocrinology · Lombard, IL
Practice pattern: Clinical Cardiology
— Primarily office-based clinical cardiology
Low-engagement
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 →
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What this data tells you about Dr. Zajac
Dr. Jacek Zajac is an endocrinology specialist in Lombard, IL, with 19 years of NPI registration. Based on federal Medicare data, Dr. Zajac performed 1,264 Medicare services across 620 unique beneficiaries.
Between the years covered by Open Payments, Dr. Zajac received a total of $25,521 from 65 pharmaceutical and/or device companies across 1450 individual payments. These payments are legal, publicly disclosed under the federal Sunshine Act, and common in endocrinology. Most payments are for meals and travel — low-value interactions common across virtually all practicing physicians. 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.
✓ 19 years in practice
▲ Top 36% volume in IL
$25,521 industry payments
Medicare Practice Summary
Medicare Utilization ↗1,264
Medicare services
Top 36% in IL for endocrinology
620
Unique beneficiaries
$89
Avg. Medicare payment
Medicare patients only (65+ / disabled) · How to read this →
~67 Medicare services per year of practice
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 |
|---|---|---|---|
| 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. |
610 | $98 | $275 |
| 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. |
369 | $64 | $200 |
| Office visit, established patient (20-29 min) An office visit for an existing patient lasting between 20 and 29 minutes. The visit involves medical evaluation and management of the patient's condition. |
107 | $66 | $195 |
| 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. |
50 | $137 | $351 |
| 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. |
34 | $104 | $300 |
| New patient office visit, complex (60-74 min) | 30 | $166 | $475 |
| Hospital discharge management, 30+ min This service covers the care provided by a physician or qualified healthcare professional on the day a patient is discharged from the hospital. It requires more than 30 minutes of total time spent on the day of discharge. |
29 | $94 | $165 |
| 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. |
20 | $122 | $360 |
| Continuous glucose monitoring, sensor under skin This procedure involves continuous monitoring of blood sugar levels in tissue fluid using a sensor placed under the skin with provider-supplied equipment. |
15 | $122 | $325 |
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. A higher procedure volume generally indicates more experience with that procedure.
Industry Payment Transparency
Open Payments through 2024 ↗$25,521
Total received (2018-2024)
Avg $3,646/year across 7 years
Top 14% in IL for endocrinology
A higher payment rank reflects disclosed industry relationships (consulting, research, speaking) common among subspecialists — not wrongdoing.
65
Companies
1,450
Individual payments
All payments are legal and publicly reported · Not evidence of wrongdoing · How to interpret →
Payment profile
Industry payments classified by relationship type. Not all payments are equal — research and consulting reflect different relationships than speaking programs or meals.
Meals & Travel
Food, beverages, travel, and lodging — typically low-value
$25,521 (100.0%)
Payment trend by year
Annual totals from pharmaceutical and medical device companies.
2024
$4,453
2023
$4,519
2022
$4,039
2021
$3,600
2020
$2,584
2019
$3,235
2018
$3,092
Payments by company (2024)
Consulting
Speaking
Meals & Travel
Research
Lilly USA, LLC
$708
Xeris Pharmaceuticals, Inc.
$437
Dexcom, Inc.
$356
AIMMUNE THERAPEUTICS, INC.
$280
Amgen Inc.
$269
Novo Nordisk Inc
$246
SANOFI-AVENTIS U.S. LLC
$194
Ascensia Diabetes Care Us Inc.
$183
Boehringer Ingelheim Pharmaceuticals, Inc.
$182
RECORDATI_RARE_DISEASES_INC.
$162
Novartis Pharmaceuticals Corporation
$133
Corcept Therapeutics
$133
Tandem Diabetes Care, Inc.
$122
Bayer Healthcare Pharmaceuticals Inc.
$119
ABBVIE INC.
$111
Mannkind Corporation
$111
BETA BIONICS, INC.
$103
Radius Health, Inc.
$87
Insulet Corporation
$85
Amneal Pharmaceuticals LLC
$65
Verity Pharmaceuticals Inc.
$62
Ultragenyx Pharmaceutical Inc.
$46
AstraZeneca Pharmaceuticals LP
$42
Amphastar Pharmaceuticals, Inc.
$37
Abbott Laboratories
$34
CeQur Corporation
$28
TheracosBio, LLC
$24
Chiesi USA, Inc.
$21
Ascendis Pharma Inc
$21
IBSA Pharma Inc.
$20
Astellas Pharma US Inc
$18
Medtronic, Inc.
$13
Top 3 companies account for 33.7% of 2024 payments
All-time payments by company (2018-2024) ›
Lilly USA, LLC
$2,966
Novo Nordisk Inc
$2,325
AstraZeneca Pharmaceuticals LP
$2,082
Corcept Therapeutics
$1,276
SANOFI-AVENTIS U.S. LLC
$1,240
Mannkind Corporation
$1,167
Dexcom, Inc.
$1,072
Boehringer Ingelheim Pharmaceuticals, Inc.
$1,050
Amarin Pharma Inc.
$966
Xeris Pharmaceuticals, Inc.
$961
MannKind Corporation
$904
Amgen Inc.
$721
RECORDATI_RARE_DISEASES_INC.
$701
Radius Health, Inc.
$584
Merck Sharp & Dohme Corporation
$573
Antares Pharma, Inc.
$374
Janssen Pharmaceuticals, Inc
$362
Insulet Corporation
$328
Bayer Healthcare Pharmaceuticals Inc.
$316
Amneal Pharmaceuticals LLC
$313
Tandem Diabetes Care, Inc.
$300
IBSA Pharma Inc.
$291
AIMMUNE THERAPEUTICS, INC.
$280
Medtronic MiniMed, Inc.
$278
Bayer HealthCare Pharmaceuticals Inc.
$234
Abbott Laboratories
$228
AbbVie Inc.
$206
Medtronic, Inc.
$203
Novartis Pharmaceuticals Corporation
$200
Becton, Dickinson and Company
$187
Ascensia Diabetes Care Us Inc.
$183
DEXCOM, INC.
$175
ABBVIE INC.
$174
EUSA Pharma (US) LLC
$155
Takeda Pharmaceuticals U.S.A., Inc.
$143
Kowa Pharmaceuticals America, Inc.
$136
Valeritas, Inc.
$133
Embecta Corp.
$125
CeQur Corporation
$123
Zealand Pharma US, Inc.
$113
Amryt Pharma Holdings Ltd
$107
BETA BIONICS, INC.
$103
Astellas Pharma US Inc
$101
Merck Sharp & Dohme LLC
$98
Shire North American Group Inc
$95
AbbVie, Inc.
$84
ARBOR PHARMACEUTICALS, INC.
$75
Intuity Medical Inc
$72
Regeneron Healthcare Solutions, Inc.
$69
Verity Pharmaceuticals Inc.
$62
LifeScan, Inc.
$62
Esperion Therapeutics, Inc.
$62
Salix Pharmaceuticals, a division of Bausch Health US, LLC
$48
Ultragenyx Pharmaceutical Inc.
$46
Ipsen Biopharmaceuticals, Inc
$40
Supernus Pharmaceuticals, Inc.
$38
Amphastar Pharmaceuticals, Inc.
$37
TheracosBio, LLC
$35
Kyowa Kirin, Inc.
$23
PFIZER INC.
$22
Chiesi USA, Inc.
$21
Aytu BioScience, Inc
$21
Ascendis Pharma Inc
$21
Arbor Pharmaceuticals, Inc.
$21
VistaPharm, Inc.
$12
Top 3 companies account for 28.9% of all-time payments
Associated products mentioned in payments ›
AFREZZA · BAQSIMI · BD Nano · BD Nano 2nd Gen Pen Needle · Brenzavvy · CYCLOSET · CeQur Simplicity · Corlanor · Crysvita · DEXCOM CGM · DEXCOM G6 CGM SYSTEM · DEXCOM G6 TRANSMITTER · Dexcom CGM · Dexcom G6 Transmitter · EVENITY · EVERSENSE 365 SENSOR KIT (RETAIL) · EVERSENSE E3 SENSOR KIT - RETAIL · Edarbyclor · FARXIGA · FORTEO · FREESTYLE LIBRE · FREESTYLE LIBRE 2 · FREESTYLE LIBRE 3 · FreeStyle Libre · FreeStyle Libre 2 · FreeStyle Libre blood glucose Flash Monitoring System · GLYXAMBI · GVOKE HYPOPEN · GVOKE PFS · Guardian Connect · HUMULIN · INVOKANA · ISTURISA · InPen · JANUVIA · JARDIANCE · Kerendia · Korlym · LANTUS · LEQVIO · LICART · LOKELMA · Livalo · MINIMED 770G · MINIMED 780G · MOUNJARO · MYCAPSSA · Minimed 670G System · Minimed 770G System · Myrbetriq · NATPARA (PARATHYROID HORMONE) · NEXLETOL · NOCDURNA · Natesto · Omnipod · OneTouch · OneTouch Verio Reflect · Ozempic · PRALUENT · PRALUENT ALIROCUMAB INJECTION · PREVNAR 20 · Pogo Automatic Blood Glucose Monitoring System · Prolia · RECORLEV · RYBELSUS · Repatha · Rybelsus · SIGNIFOR LAR · SOLIQUA · SOLIQUA 100/33 · SOMATULINE DEPOT · STEGLATRO · SYMBICORT · SYNJARDY · SYNTHROID · Saxenda · Somatuline Depot · Sylvant · Synthroid · TEPEZZA · TLANDO · TOUJEO · TRADJENTA · TRULICITY · TZIELD · Thyquidity · Tirosint · Tlando · Tresiba · Tymlos · UNITHROID · V-GO · V-GO DISPOSABLE INSULIN DELIVERY · Vascepa · Veozah · Victoza · Wegovy · XYOSTED · ZEGALOGUE · ZENPEP · iLet Bionic Pancreas · t-slim insulin pump · t:slim X2 Insulin Pump with Control-IQ · t:slim X2 insulin pump
Should you be concerned? Payments from pharmaceutical and device companies are legal and common — 57% of U.S. physicians receive at least one. They often reflect legitimate consulting, research, or education. 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 →
Most payments (100%) are for meals and travel — low-value interactions that are common across virtually all practicing physicians.
Geographic Context
Endocrinologists within 10 mi
227
Per 100K population
24.5
County median income
$110,502
Nearest hospital
ELMHURST MEMORIAL HOSPITAL
4.2 mi
4.2 mi
Data Sources
| Provider Registry | ✓ NPPES | Weekly updates |
| Medicare Enrollment | ✓ PECOS | Monthly updates |
| Practice Data | ✓ Medicare Util. | Annual (CY lag) |
| Industry Payments | ✓ Open Payments | CY 2024 |
| Disciplinary History | — Not public | 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 clinical cardiology specialist, with moderate Medicare volume, with low-engagement industry engagement in the top 14% of IL peers, with 19 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 office visit, established patient (30-39 min)?
Based on Medicare claims data, Dr. Zajac performed 610 office visit, established patient (30-39 min) services. Research suggests that higher procedure volume is often associated with better outcomes, particularly for complex procedures. Note that Medicare data only captures patients aged 65 and older, so the total practice volume across all patients is likely higher.
Does Dr. Zajac receive payments from pharmaceutical companies?
Yes. Dr. Zajac received a total of $25,521 from 65 companies across 1,450 individual payments. These payments are legal, publicly disclosed under the federal Sunshine Act, and common among physicians — 57% of all U.S. physicians receive at least one industry payment. 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 endocrinologists in Lombard?
Dr. Zajac's average Medicare payment per service is $89. 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 a long track record of practice, Medicare participation, and industry disclosure. 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?
Each data source has its own update cycle. Provider registry data (NPPES) is updated weekly. Medicare enrollment (PECOS) is updated monthly. Medicare practice data has a ~2 year lag — the most recent available is typically 2 years prior. Industry payment data (Open Payments) is published annually, usually in June, covering the prior calendar year. We display the data date prominently on each section so you always know how current it is. See our data freshness policy →
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About this page
All data on this page is sourced verbatim from public federal records published by the U.S. Centers for Medicare & Medicaid Services (CMS): 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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