Dr. William Chen, MD
What this data tells you about Dr. Chen
Dr. William Chen is an allergy & immunology specialist in San Pablo, CA, with 19 years of NPI registration. Based on federal Medicare data, Dr. Chen performed 3,078 Medicare services across 1,739 unique beneficiaries.
Between the years covered by Open Payments, Dr. Chen received a total of $7,684 from 31 pharmaceutical and/or device companies across 411 individual payments. These payments are legal, publicly disclosed under the federal Sunshine Act, and common in allergy & immunology. 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. Chen 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.
Medicare Practice Summary
Medicare Utilization ↗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 (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. |
1,654 | $66 | $180 |
| Annual wellness visit, follow-up A follow-up annual wellness visit that includes a personalized prevention plan of service. |
295 | $153 | $350 |
| Flu vaccine administration This procedure involves the administration of the influenza virus vaccine. It covers the process of delivering the vaccine to the patient. |
232 | $36 | $60 |
| Flu vaccine, high-dose High-dose seasonal influenza vaccine for adults aged 65 and older. Contains four times the antigen of standard-dose flu vaccines (60 mcg per strain), split-virus formulation, preservative-free, single-dose syringe. |
203 | $72 | $100 |
| Assessment of emotional or behavioral problems An evaluation to identify and understand emotional or behavioral issues. This process involves reviewing symptoms and behaviors to determine the nature of the concerns. |
196 | $4 | $60 |
| 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. |
130 | $92 | $254 |
| Home health plan of care re-certification A physician reviews the patient's status and contacts the home health agency to re-certify the plan of care without the patient being present. |
72 | $38 | $91 |
| SARS-CoV-2 vaccine, 30 mcg/0.3 mL Administration of the SARS-CoV-2 (COVID-19) vaccine containing 30 micrograms of antigen in a 0.3 milliliter dose. |
69 | $48 | $70 |
| Annual alcohol misuse screening, 5 to 15 minutes | 50 | $23 | $50 |
| Drug injection, under skin or into muscle A procedure involving the administration of a medication or substance via injection into the subcutaneous tissue or muscle. |
44 | $12 | $60 |
| Influenza vaccine, quadrivalent, 0.5 ml dosage | 30 | $20 | $60 |
| Electrocardiogram (EKG), 12-lead A standard heart rhythm test using at least 12 leads to record electrical activity. A healthcare provider interprets the results and provides a written report. |
25 | $12 | $75 |
| Office visit, established patient (10-19 min) An office visit for an existing patient lasting 10 to 19 minutes. The visit involves medical evaluation and management of the patient's condition. |
21 | $40 | $132 |
| Smoking cessation counseling, 4-10 minutes A brief counseling session focused on helping patients quit smoking and tobacco use. The provider spends 4 to 10 minutes discussing strategies and support for cessation. |
20 | $17 | $60 |
| Initial preventive physical examination, new Medicare beneficiary A comprehensive preventive health visit for new Medicare beneficiaries during their first 12 months of enrollment. The service is conducted as a face-to-face visit and is limited to preventive care. |
15 | $194 | $350 |
| Pneumococcal conjugate vaccine (PCV20) An intramuscular injection of the 20-valent pneumococcal conjugate vaccine. It is used to protect against diseases caused by Streptococcus pneumoniae bacteria. |
11 | $282 | $380 |
| Pneumonia vaccine administration This procedure involves the injection of a vaccine to protect against pneumococcal disease. It is administered by a healthcare provider. |
11 | $36 | $60 |
Industry Payment Transparency
Open Payments through 2024 ↗Payment profile
Industry payments classified by relationship type. Not all payments are equal — research and consulting reflect different relationships than speaking programs or meals.
Payment trend by year
Annual totals from pharmaceutical and medical device companies.
Payments by company (2024)
All-time payments by company (2018-2024) ›
Associated products mentioned in payments ›
Most payments (98%) are for meals and travel — low-value interactions that are common across virtually all practicing physicians.
Geographic Context
9.4 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. Chen is a clinical cardiology specialist, with moderate Medicare volume, with low-engagement industry engagement, 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
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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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