Physician Profile
Unclaimed ProfileAbout TIMMERMAN
Based in Los Angeles, CA, John Matthew Timmerman, MD is listed in the NPI registry under hematology/oncology. John graduated from Boston University School of Medicine in 1991. John is also listed as specializing in hematology & oncology and internal medicine. According to Medicare claims data, John cared for 269 Medicare patients across 624 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
- (310) 794-5511
- Email not available
Practice Locations
200 MEDICAL PLAZA #365,530,420,120
Los Angeles, CA 90095
Procedures Most Often Billed to Medicare
624 services · 269 patients · 9 distinct codes
| Procedure | Type | Code | Services |
|---|---|---|---|
| Subsequent hospital care with moderate levelof medical decision making, if using time, at least 50 minutes | Office visit | 99233 |
299 |
| Established patient office or other outpatient visit with moderate level of decision making, if using time, 30 minutes or more | Office visit | 99214 |
89 |
| Complete blood cell count (red cells, white blood cell, platelets), automated test and automated differential white blood cell count | Lab test | 85025 |
67 |
| Blood test, comprehensive group of blood chemicals | Lab test | 80053 |
56 |
| Established patient office or other outpatient visit with low level od decision making, if using time, 20 minutes or more | Office visit | 99213 |
34 |
| Hospital discharge day management, more than 30 minutes | Office visit | 99239 |
25 |
| Established patient office or other outpatient visit with high level of medical decision making, if using time, 40 minutes or more | Office visit | 99215 |
22 |
| Lactate dehydrogenase (enzyme) level | Lab test | 83615 |
19 |
| Initial hospital care with moderate level of medical decision making, if using time, at least 75 minutes | Office visit | 99223 |
13 |
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.
Related specialists at this location 3
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.
Other hematology/oncology specialists in Los Angeles 8
Same specialty, same city.
More connections — 16 related providers in 2 groups
Trained at Boston University School of Medicine 8
Other providers in the same specialty who trained at the same institution.
Class of 1991 at Boston University School of Medicine 8
Providers who graduated from the same medical school in the same year.
Common questions
What kind of doctor is Dr. Timmerman?
Dr. Timmerman is a hematology/oncology in Los Angeles, CA. This is the primary taxonomy recorded against the NPI in the federal registry, listed there as “HEMATOLOGY/ONCOLOGY”.
NPI registry
What is Dr. Timmerman's address?
Dr. Timmerman is listed at 200 MEDICAL PLAZA #365,530,420,120, Los Angeles, CA 90095. 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. Timmerman?
The number on file is (310) 794-5511. Guide.md cannot book appointments or pass on messages — please call the office directly.
NPI registry
What is Dr. Timmerman's NPI number?
Dr. Timmerman's National Provider Identifier is 1891715090. 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. Timmerman train?
Dr. Timmerman attended Boston University School of Medicine, graduating in 1991. This comes from the CMS National Downloadable File.
CMS public data
How long has Dr. Timmerman been practicing?
Dr. Timmerman has 35 years experience. Calculated from a graduation year of 1991, reported in the CMS National Downloadable File.
CMS public data
What procedures does Dr. Timmerman perform?
According to Medicare billing data, Dr. Timmerman the Medicare record under this individual NPI shows mainly office visits and diagnostic testing. Hospital-based physicians usually have their procedural work billed by the facility rather than under their own number, so this is a floor on their practice, not a description of it. This reflects Medicare patients only and is billing volume, not a measure of quality.
Medicare claims
Has Dr. Timmerman confirmed this information?
Not yet. This profile is built from public federal data and has not been confirmed by Dr. Timmerman. 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.