Dr. Gustavo A. Diaz, MD
- Medicare services, 2021
- 92
- Part D claims, 2024
- 31
- Industry payments
- $73
- Affiliated sites
- 4
- Medical groups
- 4
- Practice address
- 100 Wilson Rd, Monterey, CA 93940
- Practice phone
- Call (831) 422-7777
- Professional email
- Get professional email
- Personal email
- Get personal email
- Mobile number
- Get mobile number
Primary practice
Doctors on Duty
Urgent Care Center · Monterey, California
Find Dr. Diaz's professional email, personal email and mobile number
Dmand AI checks each channel through healthcare-specific waterfall enrichment. See what is on file with a free account, with practice phones, licenses and affiliations.
Dr. Gustavo A. Diaz is an emergency medicine physician in Seaside, California
Dr. Diaz practices at Doctors on Duty in Monterey, California.
Dr. Diaz's NPI, 1538122635, was assigned on April 10, 2006. Dr. Diaz graduated from UTMB Health in 1982. Dr. Diaz's California license number on file is C54872.
- NPI
- 1538122635NPI Registry (opens in a new tab)
- Medicare PAC ID
- 1254374713
- NPI enumeration date
- April 10, 2006
- NPI status
- Active
- Accepts Medicare assignment
- Yes
- Practice phone
- (831) 422-7777
- Professional email
- Get email
- Personal email
- Get email
- Mobile number
- Get number
- Sex
- Male
- Estimated age
- 70
- Medical school graduation
- 1982
Sources: NPPES NPI Registry (CMS); Dmand AI Professional Profile Data; Dmand AI Affiliation Data; and Doctors and Clinicians National Downloadable File (CMS)
Dr. Gustavo A. Diaz practices in Monterey and Seaside
Dr. Diaz's primary practice is Doctors on Duty, at 100 Wilson Rd, Monterey, CA 93940. The practice phone is (831) 422-7777. Dr. Diaz also practices at Doctors on Duty Medical Group, Inc, 1513 Fremont Blvd, Seaside, CA 93955.
- Doctors on DutyPrimary100 Wilson Rd, Monterey, CA 93940Phone(831) 422-7777
- Doctors on Duty Medical Group, Inc1513 Fremont Blvd, Seaside, CA 93955 · Monterey CountyPhone(831) 422-7777
Sources: NPPES NPI Registry (CMS); Dmand AI Affiliation Data; and Dmand AI Practice Data
Dr. Gustavo A. Diaz is affiliated with 4 sites of care and 4 medical groups
Dr. Diaz's primary practice is Doctors on Duty in Monterey, California. The medical group on file is Doctors on Duty Medical Clinics. Dmand AI also links Dr. Diaz to 3 more group practices and clinics and 3 medical groups, each named with a free account. Dr. Diaz's employer is on file too: an urgent care center.
Sources: Dmand AI Affiliation Data; and Dmand AI Org Hierarchy Data
Dmand AI tracks the EHR system at Dr. Gustavo A. Diaz's practice
Dmand AI tracks the electronic health record (EHR) system at each site where Dr. Diaz practices, 4 sites in all. Vendor and product names are available with a free account.
| Site | EHR vendor and product |
|---|---|
| Doctors on Duty | Available with a free account |
| +3 more sites and 3 medical groups | Available with a free account |
Source: Dmand AI Technology Install Data
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Dr. Gustavo A. Diaz is one of 7,423 emergency medicine physicians in California
Emergency medicine is Dr. Diaz's primary specialty in the NPI Registry, under taxonomy code 207P00000X. Dr. Diaz is board certified in emergency medicine by the American Board of Emergency Medicine. Dmand AI has Dr. Diaz's licenses on file in 6 states: California, Florida, New Hampshire, Illinois, Texas and Massachusetts.
Specialties and state licenses
- Emergency medicine, CaliforniaPrimary
- Florida license
- New Hampshire license
- Illinois license
- Texas license
- Massachusetts license
Emergency medicine physicians near Dr. Diaz
Counts of emergency medicine physicians with a Dmand AI profile, by place and practice. Each opens the list.
Sources: NPPES NPI Registry (CMS); Dmand AI Professional Profile Data; and Dmand AI Peer Benchmarks
Dr. Gustavo A. Diaz billed Medicare for 92 services in 2021
CMS data shows 92 Medicare services from Dr. Diaz across 4 procedure codes in 2021. Medicare paid $4,782 for them. Every service was in an office.
Dr. Diaz's Medicare services by type, 2020 to 2021
- 2020
- 2021
- Office and hospital visits
- 2020: 1102021: 5253%
- Lab and pathology
- 2020: 222021: 4082%
Dr. Diaz compared with the California median for emergency medicine physicians, 2021
- Dr. Diaz
- California median
- Medicare services
- 92vs 26565% below
- Part D claims
- 23vs 6263% below
Medians across 7,079 emergency medicine physicians in California with Dmand AI profiles that report each measure.
Dr. Diaz's most billed Medicare procedure codes, 2021
CMS publishes codes billed for 11 or more Medicare patients. Each label is the code family; CPT descriptions are licensed by the AMA.
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Medicare shows one payer. Book a meeting to get commercial claims data for Dr. Diaz and other emergency medicine physicians in California.
Sources: Medicare Physician & Other Practitioners - by Provider and Service (CMS), 2024 data; and Dmand AI Peer Benchmarks
Dr. Gustavo A. Diaz's patients have a median age of 38
Across all payers, Dmand AI patient panel data puts Dr. Diaz's median patient age at 38, with 49% women.
Dr. Diaz's patients across all payers
Dmand AI patient panel data covers Medicare, Medicaid and commercial patients.
Patient panel by age, all payers
Median age 38
Patient panel by sex, all payers
- Women49%
- Men51%
Source: Dmand AI Patient Panel Data
Dr. Gustavo A. Diaz wrote 31 Medicare Part D claims in 2024
In 2024, Dr. Diaz wrote 31 Medicare Part D claims for 16 patients. 100% of them were for generic drugs. CMS names the drug for 23 of them, across 2 drugs with 11 or more claims each, at $461 in total drug cost. In 2022, CMS named 34 claims across 2 drugs.
Dr. Diaz's most prescribed drugs by claims, 2023
CMS names a drug when it has 11 or more claims. Share is of the claims for drugs CMS names.
Part D claims for drugs CMS names, 2022 to 2023
- 2022
- 2023
- Claims for drugs CMS names
- 2022: 342023: 2332%
Drugs named by CMS: 2 in 2023, 2 in 2022.
Sources: Medicare Part D Prescribers - by Provider and Drug (CMS), 2024 data, released May 6, 2026; and Medicare Part D Prescribers - by Provider (CMS), 2024 data
How Dr. Gustavo A. Diaz takes part in Medicare
Dr. Diaz accepts Medicare assignment, so Medicare's approved amount is taken as full payment.
- Accepts Medicare assignment
- Yes
Source: Doctors and Clinicians National Downloadable File (CMS)
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Dr. Gustavo A. Diaz received $73 in industry payments from 2017 to 2025
CMS Open Payments shows 2 general payments to Dr. Diaz from 2 drug and device companies from 2017 to 2025. Food and beverage make up the largest share, 100% of the total. AstraZeneca Pharmaceuticals LP paid the most, $38.
General payments to Dr. Diaz by program year, 2017 to 2025
Companies that paid Dr. Diaz the most, 2017 to 2025
Share is of all general payments to this clinician.
Source: Open Payments (CMS), 2025 data, released July 7, 2026
Dr. Gustavo A. Diaz graduated from UTMB Health
Dr. Diaz graduated from UTMB Health in 1982.
- Medical school
- Board certified in emergency medicine
Source: Dmand AI Professional Profile Data
Dr. Gustavo A. Diaz accepts plans from 6 insurance carriers
Dr. Diaz is in network with 6 carriers, including Elevance, Blue Cross Blue Shield of Michigan and Blue Cross Blue Shield of Massachusetts. Medicare plans come from the most carriers, 6. Check the plan with the practice before a visit.
- Elevance
- Blue Cross Blue Shield of Michigan
- Blue Cross Blue Shield of Massachusetts
- HCSC
- Regence Health Plans
- CMS Medicare
Plan types Dr. Diaz accepts, by number of carriers
- Medicare6
- PPO5
- HMO2
- POS2
- EPO1
Source: Dmand AI Insurance Network Data
Sources for Dr. Gustavo A. Diaz's profile data
| Data on this page | Source |
|---|---|
| NPI, name, sex, specialty and licenses | NPPES NPI Registry (CMS) (opens in a new tab)Dmand AI Professional Profile Data |
| Practice locations and phone | NPPES NPI Registry (CMS) (opens in a new tab)Dmand AI Affiliation DataDmand AI Practice Data |
| Primary practice, affiliations and health system | Dmand AI Affiliation DataDmand AI Org Hierarchy Data |
| Medicare services and procedure codes | Medicare Physician & Other Practitioners - by Provider and Service (CMS) (opens in a new tab) |
| State medians for the same specialty | Dmand AI Peer Benchmarks |
| Medicare patients and the all-payer patient panel | Dmand AI Patient Panel Data |
| Part D prescribing | Medicare Part D Prescribers - by Provider and Drug (CMS) (opens in a new tab)Medicare Part D Prescribers - by Provider (CMS) (opens in a new tab) |
| MIPS scores, telehealth, assignment and procedure percentiles | Doctors and Clinicians National Downloadable File (CMS) (opens in a new tab) |
| Industry payments | Open Payments (CMS) (opens in a new tab) |
| Training, board certification and memberships | Dmand AI Professional Profile Data |
| Insurance carriers and plan types | Dmand AI Insurance Network Data |
| EHR at each practice site | Dmand AI Technology Install Data |
| Similar physicians | Dmand AI Affiliation Data |
Data last refreshed October 2026Report an inaccuracyRemove my information
FAQ
Frequently asked questions about Dr. Gustavo A. Diaz
Spotted something out of date? Email hello@dmand.ai and we will check the record. Contact details live in the free trial.
What is Dr. Gustavo A. Diaz's NPI number?
Dr. Gustavo A. Diaz's NPI number is 1538122635. It was assigned on April 10, 2006, and it is active in the NPI Registry.
What kind of doctor is Dr. Gustavo A. Diaz?
Dr. Gustavo A. Diaz is an emergency medicine physician in Seaside, California. The primary specialty in the NPI Registry is Emergency Medicine Physician (taxonomy code 207P00000X).
Where does Dr. Gustavo A. Diaz practice?
Dr. Diaz practices at 100 Wilson Rd, Monterey, CA 93940. Dr. Diaz also practices at 1513 Fremont Blvd, Seaside, CA 93955. Dr. Diaz's primary practice is Doctors on Duty in Monterey, California. Dmand AI also links Dr. Diaz to 3 group practices and clinics and 3 medical groups.
What is Dr. Gustavo A. Diaz's office phone number?
The practice phone on file for Dr. Diaz is (831) 422-7777.
What is Dr. Gustavo A. Diaz's medical license number?
Dr. Diaz's California license number on file is C54872, one of the licenses on file in 6 states.
Which states has Dr. Gustavo A. Diaz been licensed in?
Dmand AI has state licenses on file for Dr. Diaz in California (2011 to 2025), Florida (since 2020), New Hampshire (since 2009), Illinois (2023 to 2026), Texas (1983 to 2026) and Massachusetts (1984 to 2017).
What medical group is Dr. Gustavo A. Diaz part of?
Dr. Diaz is linked to Doctors on Duty Medical Clinics. Dmand AI links Dr. Diaz to 3 more medical groups.
Does Dr. Gustavo A. Diaz accept Medicare?
Yes. CMS data shows Dr. Diaz billed Medicare for 92 services in 2021, and Dr. Diaz accepts Medicare assignment.
Is Dr. Gustavo A. Diaz board certified?
Yes. Dr. Diaz is board certified in emergency medicine by the American Board of Emergency Medicine.
What services does Dr. Gustavo A. Diaz bill to Medicare?
In 2021, Dr. Diaz's most billed Medicare services were office visit, new patient (99203), lab and pathology test (87635) and office visit, established patient (99213).
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Where did Dr. Gustavo A. Diaz go to medical school?
Dr. Diaz graduated from UTMB Health in 1982.
What drugs does Dr. Gustavo A. Diaz prescribe most?
In 2023 Medicare Part D data, Dr. Diaz's most prescribed drugs by claims were Paxlovid (Eua) and Doxycycline Hyclate.
Has Dr. Gustavo A. Diaz received payments from drug or device companies?
CMS Open Payments shows $73 in general payments to Dr. Diaz from 2 companies from 2017 to 2025. The largest total came from AstraZeneca Pharmaceuticals LP.
How long has Dr. Gustavo A. Diaz been practicing?
Dr. Diaz graduated from medical school in 1982, 44 years ago.
What insurance does Dr. Gustavo A. Diaz accept?
Dr. Diaz is in network with 6 carriers, including Elevance, Blue Cross Blue Shield of Michigan and Blue Cross Blue Shield of Massachusetts. Medicare plans come from the most carriers, 6. Check the plan with the practice before a visit.
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