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Dr. Mary Ann H. Trephan, MD
NPI1891752614PAC ID0648177501
- Medicare services, 2024
- 568
- Medicare patients, 2024
- 355
- Part D claims, 2024
- 339
- Publications
- 2
- Affiliated sites
- 3
- Practice address
- 2103 E Gonzales Rd, Oxnard, CA 93036
- Practice phone
- Call (805) 650-4700
- Professional email
- Get professional email
- Personal email
- Get personal email
- Mobile number
- Get mobile number
Primary practice
Southern California Permanente Medical Group
Oxnard, California
Find Dr. Trephan's professional email, personal email and mobile number
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Dr. Mary Ann H. Trephan is an emergency medicine physician in Oxnard, California
Dr. Trephan practices at Southern California Permanente Medical Group in Oxnard, California.
Dr. Trephan's NPI, 1891752614, was assigned on April 26, 2006. Dr. Trephan graduated from Sidney Kimmel Medical College in 1993. Dr. Trephan holds California license G85040.
NPI and contact details
- NPI
- 1891752614NPI Registry (opens in a new tab)
- Medicare PAC ID
- 0648177501
- NPI enumeration date
- April 26, 2006
- NPI status
- Active
- Accepts Medicare assignment
- Yes
- Practice phone
- (805) 650-4700
- Professional email
- Get email
- Personal email
- Get email
- Mobile number
- Get number
- Sex
- Female
- Estimated age
- 59
- Medical school graduation
- 1993
Sources: NPPES NPI Registry (CMS); Dmand AI Professional Profile Data; Dmand AI Practice Data; and Doctors and Clinicians National Downloadable File (CMS)
Dr. Mary Ann H. Trephan practices at Southern California Permanente Medical Group in Oxnard, California
Dr. Trephan's primary practice is Southern California Permanente Medical Group, at 2103 E Gonzales Rd, Oxnard, CA 93036 in Ventura County. The practice phone is (805) 650-4700.
- Southern California Permanente Medical Group2103 E Gonzales Rd, Oxnard, CA 93036 · Ventura CountyPhone(805) 650-4700
Sources: NPPES NPI Registry (CMS); and Dmand AI Practice Data
Dr. Mary Ann H. Trephan is affiliated with 4 sites of care and 3 medical groups
Dr. Trephan's primary practice is Southern California Permanente Medical Group in Oxnard, California. The medical group on file is Southern California Permanente Medical Group. Dmand AI also links Dr. Trephan to 3 more group practices and clinics and 2 medical groups, each named with a free account.
Southern California Permanente Medical GroupPrimary
Sources: NPPES NPI Registry (CMS); Dmand AI Practice Data; and Dmand AI Affiliation Data
Dmand AI tracks the EHR system at Dr. Mary Ann H. Trephan's practice
Dmand AI tracks the electronic health record (EHR) system at each site where Dr. Trephan practices, 3 sites in all. Vendor and product names are available with a free account.
| Site | EHR vendor and product |
|---|---|
| Southern California Permanente Medical Group | Available with a free account |
| +3 more sites and 2 medical groups | Available with a free account |
Source: Dmand AI Technology Install Data
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Dr. Mary Ann H. Trephan is one of 7,423 emergency medicine physicians in California
Emergency medicine is Dr. Trephan's primary specialty in the NPI Registry, under taxonomy code 207P00000X. Dr. Trephan is board certified in emergency medicine by the American Board of Emergency Medicine. Dmand AI has Dr. Trephan's licenses on file in 2 states: California and Pennsylvania.
Specialties and state licenses
- Emergency medicine, CaliforniaPrimary
- Pennsylvania license
Emergency medicine physicians near Dr. Trephan
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. Mary Ann H. Trephan billed Medicare for 568 services in 2024
CMS data shows 568 Medicare services from Dr. Trephan across 11 procedure codes in 2024, for 355 Medicare patients. Medicare paid $35,938 for them. Every service was in an office.
Medicare services, 2024568
Medicare patients355
Paid by Medicare$35,938
Procedure codes11
Dr. Trephan's Medicare services by type, 2023 to 2024
- 2023
- 2024
- Office and hospital visits
- 2023: 4532024: 36719%
- Lab and pathology
- 2023: 2422024: 12648%
- Imaging
- 2023: 492024: 5410%
- Tests and treatments
- 2023: 202024: 215%
- Surgery
- 2023: 292024: 0100%
Dr. Trephan compared with the California median for emergency medicine physicians, 2024
- Dr. Trephan
- California median
- Medicare services
- 568vs 2652.1 times
- Medicare patients
- 355vs 24346% above
- Part D claims
- 236vs 623.8 times
Medians across 7,079 emergency medicine physicians in California with Dmand AI profiles that report each measure.
Dr. Trephan's most billed Medicare procedure codes, 2024
CMS publishes codes billed for 11 or more Medicare patients. Each label is the code family; CPT descriptions are licensed by the AMA.
Need commercial claims for Dr. Trephan?
Medicare shows one payer. Book a meeting to get commercial claims data for Dr. Trephan 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. Mary Ann H. Trephan treated 355 Medicare patients in 2024, average age 74
CMS counts 355 Medicare patients who saw Dr. Trephan in 2024. The largest group is 65 to 74, with 191 patients. 75% of them have high cholesterol, and 67% have high blood pressure. 5% are also on Medicaid. Their average risk score is 0.97, where 1.00 is the Medicare average.
Across all payers, Dmand AI patient panel data puts Dr. Trephan's median patient age at 41, with 62% women.
Medicare patients, 2024355
Average age74
Average risk score0.97
Also on Medicaid5%
Dr. Trephan's Medicare patients by age, 2024
CMS leaves out age groups with fewer than 11 patients.
Dr. Trephan's Medicare patients by sex, 2024
- Women21661%
- Men13939%
Chronic conditions among Dr. Trephan's Medicare patients, 2024
- High cholesterol75%
- High blood pressure67%
- Arthritis56%
- Ischemic heart disease28%
- Anxiety26%
- Diabetes23%
- Osteoporosis23%
- Mood disorders22%
Share of Medicare patients with each condition. A patient can have several.
Dr. Trephan's patients across all payers
Dmand AI patient panel data covers Medicare, Medicaid and commercial patients.
Patient panel by age, all payers
Median age 41
Patient panel by sex, all payers
- Women62%
- Men38%
Sources: Dmand AI Patient Panel Data; and Medicare Physician & Other Practitioners - by Provider (CMS), 2024 data
Dr. Mary Ann H. Trephan wrote 339 Medicare Part D claims in 2024
In 2024, Dr. Trephan wrote 339 Medicare Part D claims for 252 patients. 91% of them were for generic drugs. CMS names the drug for 236 of them, across 7 drugs with 11 or more claims each, at $1,946 in total drug cost. In 2023, CMS named 290 claims across 10 drugs.
Part D claims, 2024339
Drugs named by CMS7
Total drug cost$1,946
Part D patients252
Dr. Trephan's Part D claims by kind of drug, 2024
- Generic309 claims91%
- Brand-name and other30 claims9%
Dr. Trephan's most prescribed drugs by claims, 2024
CMS names a drug when it has 11 or more claims. Share is of the claims for drugs CMS names.
Drug classes CMS tracks in Dr. Trephan's Part D claims, 2024
- Antibiotics46%157 of 339 claims
Share of all Part D claims for each drug class CMS reports on. Classes with no claims are left out.
Part D claims for drugs CMS names, 2023 to 2024
- 2023
- 2024
- Claims for drugs CMS names
- 2023: 2902024: 23619%
Drugs named by CMS: 7 in 2024, 10 in 2023.
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. Mary Ann H. Trephan takes part in Medicare
Dr. Trephan 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. Mary Ann H. Trephan has 2 publications on record
Dmand AI links 2 papers to Dr. Trephan. Dr. Trephan's most frequent co-authors are Kirsten A. Bechtel, MD and Raquel L. Rissman, MD.
Papers2
Dr. Trephan's most frequent co-authors
Recent publications by Dr. Trephan
See who Dr. Trephan researches with
Physician Network Discovery turns co-authorship, shared hospitals and shared groups into a map of who Dr. Trephan works with, so you can find a warm path to the right emergency medicine physicians.
Sources: PubMed (National Library of Medicine); and Dmand AI Research Linkage
Dr. Mary Ann H. Trephan graduated from Sidney Kimmel Medical College
Dr. Trephan graduated from Sidney Kimmel Medical College in 1993.
- Medical school
- Board certified in emergency medicine
Source: Dmand AI Professional Profile Data
Dr. Mary Ann H. Trephan accepts plans from 8 insurance carriers
Dr. Trephan is in network with 8 carriers, including Kaiser Permanente, Blue Cross Blue Shield of Massachusetts and Blue Cross Blue Shield of Michigan. Medicare plans come from the most carriers, 6. Check the plan with the practice before a visit.
- Kaiser Permanente
- Blue Cross Blue Shield of Massachusetts
- Blue Cross Blue Shield of Michigan
- HCSC
- Regence Health Plans
- CMS Medicare
- GA State Medicaid
- Molina
Plan types Dr. Trephan accepts, by number of carriers
- Medicare6
- PPO4
- EPO1
- HMO1
- Medicaid1
- POS1
Source: Dmand AI Insurance Network Data
Sources for Dr. Mary Ann H. Trephan'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 Practice Data |
| Primary practice, affiliations and health system | NPPES NPI Registry (CMS) (opens in a new tab)Dmand AI Practice DataDmand AI Affiliation 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 DataMedicare Physician & Other Practitioners - by Provider (CMS) (opens in a new tab) |
| 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) |
| Publications, topics and co-authors | PubMed (National Library of Medicine) (opens in a new tab)Dmand AI Research Linkage |
| 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. Mary Ann H. Trephan
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. Mary Ann H. Trephan's NPI number?
Dr. Mary Ann H. Trephan's NPI number is 1891752614. It was assigned on April 26, 2006, and it is active in the NPI Registry.
What kind of doctor is Dr. Mary Ann H. Trephan?
Dr. Mary Ann H. Trephan is an emergency medicine physician in Oxnard, California. The primary specialty in the NPI Registry is Emergency Medicine Physician (taxonomy code 207P00000X).
Where does Dr. Mary Ann H. Trephan practice?
Dr. Trephan practices at 2103 E Gonzales Rd, Oxnard, CA 93036. Dr. Trephan's primary practice is Southern California Permanente Medical Group in Oxnard, California. Dmand AI also links Dr. Trephan to 3 group practices and clinics and 2 medical groups.
What is Dr. Mary Ann H. Trephan's office phone number?
The practice phone on file for Dr. Trephan is (805) 650-4700.
What is Dr. Mary Ann H. Trephan's medical license number?
Dr. Trephan holds California license G85040, one of the licenses on file in 2 states.
Which states has Dr. Mary Ann H. Trephan been licensed in?
Dmand AI has state licenses on file for Dr. Trephan in California (1999 to 2027) and Pennsylvania (1994 to 1998).
What medical group is Dr. Mary Ann H. Trephan part of?
Dr. Trephan is linked to Southern California Permanente Medical Group. Dmand AI links Dr. Trephan to 2 more medical groups.
Does Dr. Mary Ann H. Trephan accept Medicare?
Yes. CMS data shows Dr. Trephan billed Medicare for 568 services in 2024, and Dr. Trephan accepts Medicare assignment.
How many Medicare patients does Dr. Mary Ann H. Trephan see?
CMS counts 355 Medicare patients who saw Dr. Trephan in 2024, with an average age of 74.
Is Dr. Mary Ann H. Trephan board certified?
Yes. Dr. Trephan is board certified in emergency medicine by the American Board of Emergency Medicine.
Show 7 more questionsShow fewer questions
What services does Dr. Mary Ann H. Trephan bill to Medicare?
In 2024, Dr. Trephan's most billed Medicare services were office visit, established patient (99214), office visit, established patient (99213) and office visit, new patient (99203).
Where did Dr. Mary Ann H. Trephan go to medical school?
Dr. Trephan graduated from Sidney Kimmel Medical College in 1993.
What drugs does Dr. Mary Ann H. Trephan prescribe most?
In 2024 Medicare Part D data, Dr. Trephan's most prescribed drugs by claims were Cephalexin, Prednisone and Azithromycin.
How long has Dr. Mary Ann H. Trephan been practicing?
Dr. Trephan graduated from medical school in 1993, 33 years ago.
Does Dr. Mary Ann H. Trephan do research?
Dmand AI links 2 publications to Dr. Trephan.
Who does Dr. Mary Ann H. Trephan publish with?
Dr. Trephan's most frequent co-authors are Kirsten A. Bechtel, MD (1 shared paper) and Raquel L. Rissman, MD (1 shared paper).
What insurance does Dr. Mary Ann H. Trephan accept?
Dr. Trephan is in network with 8 carriers, including Kaiser Permanente, Blue Cross Blue Shield of Massachusetts and Blue Cross Blue Shield of Michigan. Medicare plans come from the most carriers, 6. Check the plan with the practice before a visit.
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