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- 18300 Roscoe Blvd, Northridge, CA 91328
About Dr. Trephan
Mary Ann H. Trephan, MD practices emergency medicine in Northridge, CA. Mary Ann is a 1993 graduate of Jefferson Medical College of Thomas Jefferson University. According to Medicare claims data, Mary Ann cared for 554 Medicare patients across 568 services. The services billed most often include established patient office or other outpatient visit with moderate level of decision making, if using time, 30 minutes or more, established patient office or other outpatient visit with low level od decision making, if using time, 20 minutes or more, and new patient office or other outpatient visit with low level of medical decision making, if using time, 30 minutes or more. The provider's National Provider Identifier (NPI) is 1891752614.
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
- (818) 885-8500
- Email not available
Is this your home address or personal number? Hide it
Practice Locations
18300 ROSCOE BLVD
Northridge, CA 91328
Conditions Commonly Evaluated or Treated
Within Emergency 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
Bites & Stings
Brain & Nerves
- Delirium
- Stroke
- Fainting and syncope
- Seizure in Child
- Severe headache or sudden migraine
- Status epilepticus
- Transient ischemic attack
Endocrine & Metabolic
Eye Care
Injuries & Trauma
- Animal or dog bite
- Bone fractures
- Deep cut or wound
- Dislocated joint
- Severe burn
- Sprains and muscle strains
- Traumatic brain injury
Rashes & allergy
Skin & Infections
Urinary & Bladder
Women's Health
Abdomen & Digestion
Allergy & Immune
Allergy & Immunology
Blood & Circulation
Breathing
Digestion & Stomach
Ear, Nose & Throat
Environmental
Eye Emergency
General Emergency
Heart & Chest
Heart & Circulation
Heart & Lungs
Infections & Illness
Lungs & Breathing
Men's Health
Poisoning & Environmental
Poisoning & Toxins
Spine & Back
Urinary & Kidney
Procedures & services
Abdominal Procedures
Breathing & Airway
Critical Care
- Central line placement
- Chest tube insertion
- CPR and defibrillation
- Blood transfusion
Diagnostic testing
Diagnostics
Ear, Nose & Throat
Eye & ENT
Heart & Diagnostics
Imaging & Diagnostics
Injections & Vaccines
Kidney Care
Lung & Respiratory
Medications
Mental Health
Minor Procedures
- Nasal cautery for nosebleeds
- Tick Removal
- Urinary catheter insertion
- Fishhook or embedded splinter removal
- Incision and drainage of an abscess
Minor Trauma
Orthopedics
Poisoning & Toxicology
Specialized Care
Stroke & Vascular
Toxicology
Women's Health
Wound Care
- Burn dressing and care
- Skin glue for cuts
- Stitches and Laceration Repair
- Wound cleaning and debridement
- Wound stapling
Airway & Breathing
Anesthesia & Sedation
Digestive Care
Eye Care
Heart Care
Orthopedic Procedures
Supportive Care
Procedures Most Often Billed to Medicare
568 services · 554 patients · 11 distinct codes
| Procedure | Type | Code | Services | Compared with peers |
|---|---|---|---|---|
| X-ray of chest, 2 views | Imaging | 71046 |
54 | More often than most peers in Emergency Medicine |
| Routine electrocardiogram (ecg) using at least 12 leads with interpretation and report | Treatment | 93000 |
21 | As often as other peers in Emergency Medicine |
| Established patient office or other outpatient visit with moderate level of decision making, if using time, 30 minutes or more | Office visit | 99214 |
127 | More often than most peers in Emergency Medicine |
| Established patient office or other outpatient visit with low level od decision making, if using time, 20 minutes or more | Office visit | 99213 |
102 | More often than most peers in Emergency Medicine |
| New patient office or other outpatient visit with low level of medical decision making, if using time, 30 minutes or more | Office visit | 99203 |
72 | More often than most peers in Emergency Medicine |
| New patient office or other outpatient visit with moderate level of medical decision making, if using time, 45 minutes or more | Office visit | 99204 |
66 | More often than most peers in Emergency Medicine |
| Manual urinalysis test with examination using microscope, automated | Lab test | 81001 |
36 | More often than most peers in Emergency Medicine |
| Blood test, comprehensive group of blood chemicals | Lab test | 80053 |
28 | As often as other peers in Emergency Medicine |
| Detection test by immunoassay technique for severe acute respiratory syndrome coronavirus | Lab test | 87426 |
27 | As often as other peers in Emergency Medicine |
| Complete blood cell count (red cells, white blood cell, platelets), automated test and automated differential white blood cell count | Lab test | 85025 |
20 | Less often than most peers in Emergency 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 emergency physicians at this location 2
Same specialty, same street address — most likely the same department or group.
Related specialists at this location 2
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 — 30 related providers in 4 groups
Other emergency physicians in Northridge 6
Same specialty, same city.
Trained at Jefferson Medical College of Thomas Jefferson University 8
Other providers in the same specialty who trained at the same institution.
Class of 1993 at Jefferson Medical College of Thomas Jefferson University 8
Providers who graduated from the same medical school in the same year.
Also performs X-ray of chest, 2 views 8
Providers in CA who bill this service to Medicare most often.
Common questions
What kind of doctor is Dr. Trephan?
Dr. Trephan is an emergency physician in Northridge, CA. That is the designation recorded for this NPI in the federal registry, where it is listed as “Emergency Medicine”.
NPI registry
What is Dr. Trephan's address?
Dr. Trephan is listed at 18300 Roscoe Blvd, Northridge, CA 91328. 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. Trephan?
The number on file is (818) 885-8500. Contact the office directly to confirm availability and scheduling.
NPI registry
What is Dr. Trephan's NPI number?
Dr. Trephan's National Provider Identifier is 1891752614. 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. Trephan train?
Dr. Trephan attended Jefferson Medical College of Thomas Jefferson University, graduating in 1993. This comes from the CMS National Downloadable File.
CMS public data
How long has Dr. Trephan been practicing?
Dr. Trephan has 33 years experience. Calculated from a graduation year of 1993, reported in the CMS National Downloadable File.
CMS public data
What procedures does Dr. Trephan perform?
According to Medicare billing data, Dr. Trephan performs imaging including x-ray of chest, 2 views; provides treatments such as routine electrocardiogram using at least 12 leads 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. Trephan confirmed this information?
Not yet. This profile is built from public federal data and has not been confirmed by Dr. Trephan. If this is you, claiming it is free.
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Guide.md listings do not constitute medical advice or an endorsement.