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Edit this profileAt a glance
- 1500 Post Rd., Darien, CT 06820
About Dr. Giesen
Based in Darien, CT, William J. Giesen, M.D. is listed in the NPI registry under internal medicine. William graduated from Georgetown University School of Medicine in 1975. According to Medicare claims data, William cared for 676 Medicare patients across 894 services. The services billed most often include established patient office or other outpatient visit with low level od decision making, if using time, 20 minutes or more, insertion of needle into vein for collection of blood sample, and urinalysis, manual test. NPI 1124104724 identifies this record in the national registry.
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
- (203) 655-2516
- Email not available
Is this your home address or personal number? Hide it
Practice Locations
1500 POST RD.
Darien, CT 06820
Conditions Commonly Evaluated or Treated
Within Internal Medicine 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
Cancer Prevention
Cancer risk
Environmental health
- Asbestos Exposure
- Contaminated drinking water exposure
- Heat exhaustion and heat stroke
- Radon gas exposure
- Tick bite and Lyme disease risk
- Toxic Mold Exposure
- Wildfire smoke and air pollution exposure
- Workplace Chemical Exposure
General wellness
Heart health
Infectious Disease
Infectious disease
Kidney health
Lifestyle & wellness
Lifestyle health
Longevity
Metabolic & Lifestyle
Occupational health
Occupational Health
Rashes & allergy
Sexual Health
Sexual health
Substance use
Travel health
Wellness and energy
Workplace health
Most searched conditions
Cardiometabolic
Digestive and liver
Endocrine, blood, and bone
Kidney and urinary
Respiratory
Blood & Circulation
Blood disorders
Brain & Nerves
Brain and nerves
Cardiac and vascular
Digestive
Heart & Circulation
Infections
Kidney & Bladder
Lungs & Breathing
Mental Health
Neurologic and behavioral
Pain
Rheumatologic and pain
Procedures & services
Addiction & habits
Cancer screening
Cancer Screening
Checkups & exams
Chronic illness
Diagnostics & screening
Environmental health
Fitness & body composition
Heart & Circulation
- Blood Pressure Check
- Heart monitor
Heart & circulation
Heart health
Hospital-based procedures
Imaging referral
Immunizations
Infection & Microbiology Tests
- STI and STD Screening
- H. Pylori Breath Test
Lifestyle & Prevention
Longevity
Lower endoscopy
Lungs & Breathing
Metabolic & Weight
Metabolic health
Occupational health
Occupational Health
Office Procedures
Preventive and evaluation
- Preoperative medical clearance
- Medication management
- Post-hospital transitional care
Preventive imaging
Preventive screening
Routine Blood Tests
Screening & labs
Screening and diagnostic testing
- Blood pressure screening
- Cancer screening and prevention planning
- Diabetes and prediabetes screening
- EKG
- Spirometry
Screenings & Diagnostics
Travel Health
Travel medicine
Wellness
Wellness & Screening
Workplace health
Skin growths
Sleep
Most searched procedures
Bones & Joints
Brain and nerves
Digestive
- Endoscopy
Exams & Consultations
Lab tests
Minor procedures
- Ingrown toenail removal
- Suture removal
Office procedures
- Cryotherapy for skin lesions
- Earwax removal
- Incision and drainage of an abscess
- Skin biopsy
Pain management
Preventive & Routine Care
Sexual health
Procedures Most Often Billed to Medicare
894 services · 676 patients · 10 distinct codes
| Procedure | Type | Code | Services | Compared with peers |
|---|---|---|---|---|
| Insertion of needle into vein for collection of blood sample | Procedure | 36415 |
153 | As often as other peers in Internal Medicine |
| Removal of impacted ear wax | Procedure | 69210 |
20 | As often as other peers in Internal Medicine |
| Routine electrocardiogram (ecg) using at least 12 leads with interpretation and report | Treatment | 93000 |
107 | More often than most peers in Internal Medicine |
| Test to measure expiratory airflow and volume | Treatment | 94010 |
99 | More often than most peers in Internal Medicine |
| Established patient office or other outpatient visit with low level od decision making, if using time, 20 minutes or more | Office visit | 99213 |
186 | More often than most peers in Internal Medicine |
| Urinalysis, manual test | Lab test | 81002 |
114 | More often than most peers in Internal Medicine |
| Established patient office or other outpatient visit with moderate level of decision making, if using time, 30 minutes or more | Office visit | 99214 |
97 | Less often than most peers in Internal Medicine |
| Annual wellness visit, includes a personalized prevention plan of service (pps), subsequent visit | Billing code | G0439 |
74 | As often as other peers in Internal Medicine |
| Established patient office or other outpatient visit with high level of medical decision making, if using time, 40 minutes or more | Office visit | 99215 |
31 | As often as other peers in Internal Medicine |
| Annual wellness visit; includes a personalized prevention plan of service (pps), initial visit | Billing code | G0438 |
13 | Less often than most peers in Internal Medicine |
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.
Other internists at this location 8
Same specialty, same street address — most likely the same department or group.
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 — 25 related providers in 4 groups
Trained at Georgetown University School of Medicine 8
Other providers in the same specialty who trained at the same institution.
Class of 1975 at Georgetown University School of Medicine 8
Providers who graduated from the same medical school in the same year.
Also performs Insertion of needle into vein for collection of blood sample 8
Providers in CT who bill this service to Medicare most often.
Common questions
What kind of doctor is William J. Giesen?
William J. Giesen is an internist in Darien, CT. That is the designation recorded for this NPI in the federal registry, where it is listed as “Internal Medicine”.
NPI registry
What is William J. Giesen's address?
William J. Giesen is listed at 1500 Post Rd., Darien, CT 06820. Addresses come from the NPI registry and can lag a move, so confirm before travelling.
NPI registry
How can I make an appointment with William J. Giesen?
The number on file is (203) 655-2516. Contact the office directly to confirm availability and scheduling.
NPI registry
What is William J. Giesen's NPI number?
William J. Giesen's National Provider Identifier is 1124104724. 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 William J. Giesen train?
William J. Giesen attended Georgetown University School of Medicine, graduating in 1975. This comes from the CMS National Downloadable File.
CMS public data
How long has William J. Giesen been practicing?
William J. Giesen has 51 years experience. Calculated from a graduation year of 1975, reported in the CMS National Downloadable File.
CMS public data
What procedures does William J. Giesen perform?
According to Medicare billing data, William J. Giesen performs procedures including insertion of needle into vein for collection of blood sample and removal of impacted ear wax; provides treatments such as routine electrocardiogram using at least 12 leads with interpretation and report and test to measure expiratory airflow and volume, alongside routine visits and testing. This reflects Medicare patients only and is billing volume, not a measure of quality.
Medicare claims
Has William J. Giesen confirmed this information?
Not yet. This profile is built from public federal data and has not been confirmed by William J. Giesen. If this is you, claiming it is free.
Guide.md
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