Physician Profile
Unclaimed ProfileAbout BAYER
William Bayer, MD is a healthcare provider in Carol Stream, IL specializing in endocrinology. William trained at Loyola University of Chicago, Stritch School of Medicine, graduating in 1986. William is also listed as specializing in endocrinology, diabetes & metabolism. According to Medicare claims data, William cared for 1,359 Medicare patients across 12,498 services.
Summarised automatically from public NPI registry and CMS Medicare data. Not written or reviewed by this provider. Claim this profile to replace it.
Education & Training
Areas of Expertise
Licensing & Certification
Source: NPPES NPI Registry
Contact Information
- (630) 668-3210
- Email not available
Practice Locations
501 THORNHILL DR
Carol Stream, IL 60188
Procedures Most Often Billed to Medicare
12,498 services · 1,359 patients · 10 distinct codes
| Procedure | Type | Code | Services |
|---|---|---|---|
| Insertion of needle into vein for collection of blood sample | Procedure | 36415 |
56 |
| Injection of drug or substance under skin or into muscle | Treatment | 96372 |
168 |
| Continuous monitoring of blood sugar level in tissue fluid using sensor under skin with interpretation and report | Treatment | 95251 |
116 |
| Injection, denosumab, 1 mg | Drug given | J0897 |
10,860 |
| Established patient office or other outpatient visit with moderate level of decision making, if using time, 30 minutes or more | Office visit | 99214 |
639 |
| Visit complexity inherent to evaluation and management associated with medical care services that serve as the continuing focal point for all needed health care services and/or with medical care services that are part of ongoing care related to a patient' | Billing code | G2211 |
413 |
| Hemoglobin a1c level | Lab test | 83036 |
148 |
| Subsequent hospital care with moderate levelof medical decision making, if using time, at least 35 minutes | Office visit | 99232 |
55 |
| New patient office or other outpatient visit with moderate level of medical decision making, if using time, 45 minutes or more | Office visit | 99204 |
28 |
| Initial hospital care with straightforward or low-level medical decision making, if using time, at least 55 minutes | Office visit | 99222 |
15 |
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 endocrinology specialists at this location 1
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 — 24 related providers in 3 groups
Trained at Loyola University of Chicago, Stritch School of Medicine 8
Other providers in the same specialty who trained at the same institution.
Class of 1986 at Loyola University of Chicago, Stritch 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 IL who bill this service to Medicare most often.
Common questions
What kind of doctor is Dr. Bayer?
Dr. Bayer is an endocrinology in Carol Stream, IL. This is the primary taxonomy recorded against the NPI in the federal registry, listed there as “ENDOCRINOLOGY”.
NPI registry
What is Dr. Bayer's address?
Dr. Bayer is listed at 501 THORNHILL DR, Carol Stream, IL 60188. Addresses come from the NPI registry and can lag a move, so confirm before travelling.
NPI registry
How can I make an appointment with Dr. Bayer?
The number on file is (630) 668-3210. Guide.md cannot book appointments or pass on messages — please call the office directly.
NPI registry
What is Dr. Bayer's NPI number?
Dr. Bayer's National Provider Identifier is 1528162898. 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 Dr. Bayer train?
Dr. Bayer attended Loyola University of Chicago, Stritch School of Medicine, graduating in 1986. This comes from the CMS National Downloadable File.
CMS public data
How long has Dr. Bayer been practicing?
Dr. Bayer has 40 years experience. Calculated from a graduation year of 1986, reported in the CMS National Downloadable File.
CMS public data
What procedures does Dr. Bayer perform?
According to Medicare billing data, Dr. Bayer performs procedures including insertion of needle into vein for collection of blood sample; provides treatments such as injection of drug or substance under skin or into muscle and continuous monitoring of blood sugar level in tissue fluid using sensor under skin with interpretation and report, alongside routine visits and testing. This reflects Medicare patients only and is billing volume, not a measure of quality.
Medicare claims
Has Dr. Bayer confirmed this information?
Not yet. This profile is built from public federal data and has not been confirmed by Dr. Bayer. If this is you, claiming it is free.
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Claim this profileProvider data sourced from the NPPES NPI Registry and CMS public datasets. Information is provided for reference and is not medical advice.