Physician Profile
Jacek Zajac, M.D.
Unclaimed ProfileAbout Dr. Zajac
Jacek Zajac, M.D. practices endocrinology in Lombard, IL. Jacek is also listed as specializing in endocrinology, diabetes & metabolism. According to Medicare claims data, Jacek cared for 605 Medicare patients across 1,183 services. The services billed most often include established patient office or other outpatient visit with moderate level of decision making, if using time, 30 minutes or more, subsequent hospital care with moderate levelof medical decision making, if using time, at least 35 minutes, and established patient office or other outpatient visit with low level od decision making, if using time, 20 minutes or more. The provider's National Provider Identifier (NPI) is 1396817912.
Factual summary compiled by Guide.md from public records; not written by this provider.
Education & Training
Specialty
Credentials & Licensing
Medicare information
Exactly as CMS reports it (National Downloadable File, Opt-Out Affidavits, Order & Referring). Not an insurance directory; confirm coverage with the office.
Contact Information
- (630) 629-3610
- Email not available
Practice Locations
2500 S HIGHLAND AVE STE 104
Lombard, IL 60148
Conditions Commonly Evaluated or Treated
Within Endocrinology, Diabetes and Metabolism generally. Availability varies by clinician, training and location — this profile has not been claimed, so nothing here is a personal claim by the provider.
Conditions
Most searched conditions
- Diabetes
- Hyperthyroidism
- Hypothyroidism
- Obesity
- Osteoporosis
- PCOS
- Thyroid problems
Adrenal
Adrenal disorders
- Adrenal Fatigue
- Adrenal gland tumor
- Adrenal mass
- Cushing's Syndrome
Blood sugar disorders
- Diabetic neuropathy
- Gestational diabetes
- Low Blood Sugar
- Prediabetes
Bone and calcium disorders
- High calcium
- Low Calcium
- Vitamin D deficiency
Bones
- Soft Bones
Diabetes
- Dangerous high blood sugar
- Diabetic retinopathy
- Kidney disease from diabetes
Endocrine tumors
Hormone disorders
- Early or delayed puberty
- Excess facial or body hair
- Gynecomastia
- Perimenopause
- Testosterone deficiency
Hormones
Metabolic disorders
- High cholesterol
- Metabolic syndrome
Metabolism
- Fatty liver disease
- Insulin Resistance
- Unexplained Weight Gain
Parathyroid
Pituitary
- Acromegaly
- Adult Growth Hormone Deficiency
- Underactive Pituitary Gland
Pituitary disorders
- Extreme Thirst and Urination
- High Prolactin
- Pituitary Tumor
- Short stature and growth concerns
Thyroid
- Thyroiditis
Thyroid disorders
- Goiter
- Graves' Disease
- Hashimoto's Disease
- Thyroid cancer
- Thyroid eye disease
- Thyroid nodules
Procedures & services
Most searched procedures
- Hormone replacement therapy
- Insulin pump management
- Thyroid ultrasound
- Weight loss management
Adrenal
- 24-Hour Urine Cortisol Test
- Aldosterone and Renin Blood Test
- Urine Metanephrines Test
Adrenal evaluations
- Adrenal Gland Suppression Test
- Cortisol Testing
Blood sugar management
- Continuous Glucose Monitor Placement
- Diabetes Screening and A1C Test
- Glucose screening test
Bone evaluations
- Bone Density Scan Referral
- Parathyroid Hormone Test
Bone treatments
- Bisphosphonate Infusion for Bones
- Bone Building Injections
Diabetes
- Automated Insulin System Setup
- Blood Ketone Monitoring
- C-Peptide Test
- Continuous Glucose Monitor Data Review
- Medical nutrition therapy
- Starting Insulin Therapy
Diabetes education
- Diabetes Self-Management Education
Diabetes preventive care
Genetic evaluations
- Genetic Testing for Endocrine Tumors
Hormone treatments
- Estrogen and Progesterone Therapy
- Growth Hormone Injections
- Hormone Replacement Therapy Consultation
Hormones
- Gender-affirming care consultation
Metabolic evaluations
- Cholesterol and Lipid Blood Panel
Metabolism
- Fasting Insulin Test
Parathyroid
- Parathyroid Scan
Pituitary
- Growth Hormone Stimulation Test
Pituitary evaluations
- Prolactin Blood Test
- Water Deprivation Test
Thyroid
- Thyroid Cyst Alcohol Ablation
- Thyroid Uptake and Scan
Thyroid procedures
- Radioactive Iodine Treatment
- Thyroid Antibody Testing
- Thyroid Blood Test
- Thyroid Medication Adjustment
- Thyroid Nodule Biopsy
- Thyroid Nodule Radiofrequency Ablation
Weight & Metabolism
- Weight loss medication consult
Procedures Most Often Billed to Medicare
1,183 services · 605 patients · 9 distinct codes
| Procedure | Type | Code | Services | Compared with peers |
|---|---|---|---|---|
| Continuous monitoring of blood sugar level in tissue fluid using sensor under skin with provider supplied equipment | Treatment | 95250 |
16 | Less often than most peers in Endocrinology |
| Established patient office or other outpatient visit with moderate level of decision making, if using time, 30 minutes or more | Office visit | 99214 |
555 | More often than most peers in Endocrinology |
| Subsequent hospital care with moderate levelof medical decision making, if using time, at least 35 minutes | Office visit | 99232 |
361 | More than most peers in Endocrinology |
| Established patient office or other outpatient visit with low level od decision making, if using time, 20 minutes or more | Office visit | 99213 |
100 | More often than most peers in Endocrinology |
| Initial hospital care with moderate level of medical decision making, if using time, at least 75 minutes | Office visit | 99223 |
57 | More often than most peers in Endocrinology |
| Initial hospital care with straightforward or low-level medical decision making, if using time, at least 55 minutes | Office visit | 99222 |
33 | More often than most peers in Endocrinology |
| New patient office or other outpatient visit with a high level of medical decision making, if using time, 60 minutes or more | Office visit | 99205 |
22 | As often as other peers in Endocrinology |
| Hospital discharge day management, more than 30 minutes | Office visit | 99239 |
21 | Less often than most peers in Endocrinology |
| New patient office or other outpatient visit with moderate level of medical decision making, if using time, 45 minutes or more | Office visit | 99204 |
18 | Less often than most peers in Endocrinology |
Source: CMS Medicare public data. Shows how often procedures were billed — not quality of care or patient satisfaction.
Related providers
Connections drawn from the registry and from what providers have told us. A link here is not a referral or an endorsement.
Related specialists at this location 4
Clinically related specialties at the same address — the people this provider most likely works alongside.
Also at this address 4
Providers at the same street address. Each files their own registry entry, so a shared practice often appears under several different names.
More connections — 24 related providers in 3 groups
Trained at Other 8
Other providers in the same specialty who trained at the same institution.
Class of 1991 at Other 8
Providers who graduated from the same medical school in the same year.
Also performs Continuous monitoring of blood sugar level in tissue fluid using sensor under skin with provider supplied equipment 8
Providers in IL who bill this service to Medicare most often.
Common questions
What kind of doctor is Jacek Zajac?
Jacek Zajac is an endocrinology in Lombard, IL. That is the designation recorded for this NPI in the federal registry.
NPI registry
What is Jacek Zajac's address?
Jacek Zajac is listed at 2500 S Highland Ave Ste 104, Lombard, IL 60148. Addresses come from the NPI registry and can lag a move, so confirm before travelling.
NPI registry
How can I make an appointment with Jacek Zajac?
The number on file is (630) 629-3610. Contact the office directly to confirm availability and scheduling.
NPI registry
What is Jacek Zajac's NPI number?
Jacek Zajac's National Provider Identifier is 1396817912. It is issued by the Centers for Medicare & Medicaid Services and is unique and permanent — it does not change if they move practice.
NPI registry
Where did Jacek Zajac train?
Jacek Zajac attended Other, graduating in 1991. This comes from the CMS National Downloadable File.
CMS public data
How long has Jacek Zajac been practicing?
Jacek Zajac has 35 years experience. Calculated from a graduation year of 1991, reported in the CMS National Downloadable File.
CMS public data
What procedures does Jacek Zajac perform?
According to Medicare billing data, Jacek Zajac provides treatments such as continuous monitoring of blood sugar level in tissue fluid using sensor under skin with provider supplied equipment, alongside routine visits and testing. This reflects Medicare patients only and is billing volume, not a measure of quality.
Medicare claims
Has Jacek Zajac confirmed this information?
Not yet. This profile is built from public federal data and has not been confirmed by Jacek Zajac. If this is you, claiming it is free.
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