Doctor profile · Federal record
Dr. Mark O'Brien, D.O.
Internal Medicine Physician (CMS: Internal Medicine) · Vista, CA
- NPI 1497744247
- Accepts Medicare
- 39 yrs in practice
- Male
- Group practice
- No sanctions
Practice & contact
- Primary practice
-
161 Thunder Dr Ste 210
Vista, CA 920836052
(760) 216-6500
fax (760) 295-4753
Credentials & registration
- NPI registered
- October 2005 — 21 yrs on file
- Profile last updated
- April 1, 2025
- Year of graduation
- 1987 — 39 yrs since
- Specialty taxonomy
- 207R00000X — NUCC code
- State license (1)
- California #20A6017
Federal sanctions & exclusions
No sanctions, exclusions or revocations on file
Checked against OIG LEIE on NPI 1497744247. Last verified May 11, 2026.Medicare procedures · 2023
Top services delivered
Total services
637
Distinct HCPCS
4
Medicare allowed
$77,505
| HCPCS | Description | Services | Patients | Avg allowed | |
|---|---|---|---|---|---|
99233 |
Subsequent hospital care with moderate levelof medical decision making, if using time, at least 50 minutes | 323 | 118 | $123 | |
99239 |
Hospital discharge day management, more than 30 minutes | 121 | 117 | $119 | |
99232 |
Subsequent hospital care with moderate levelof medical decision making, if using time, at least 35 minutes | 116 | 60 | $82 | |
99223 |
Initial hospital care with moderate level of medical decision making, if using time, at least 75 minutes | 77 | 76 | $180 |
In context: peer comparison
Among 14 peers in this city , average services per provider: 127. This provider delivers 5.0× the peer median.Medicare Part D · 2023
Top prescriptions
Total claims
54
Patients
39
Total drug cost
$8,963
| Drug | Type | Claims | Patients | Total cost |
|---|---|---|---|---|
| Levofloxacin | Generic | 18 | 17 | $92 |
| Eliquis (Apixaban) | Brand | 14 | 11 | $8,617 |
| Amiodarone Hcl | Generic | 11 | 0 | $127 |
| Amoxicillin-Clavulanate Potass (Amoxicillin/Potassium Clav) | Brand | 11 | 11 | $126 |
Frequently asked questions
What is Dr. Mark O'Brien's medical specialty?
Dr. Mark O'Brien practices Internal Medicine Physician in Vista, CA.
Where does Dr. Mark O'Brien practice?
Dr. Mark O'Brien practices at 161 Thunder Dr Ste 210, Vista, CA 920836052. Office phone: 7602166500.
What is Dr. Mark O'Brien's NPI?
Dr. Mark O'Brien's National Provider Identifier (NPI) is 1497744247, issued by NPPES.
Does Dr. Mark O'Brien accept Medicare assignment?
Yes. Dr. Mark O'Brien accepts Medicare assignment, meaning Medicare-allowed amounts are accepted as full payment for covered services.
What procedures does Dr. Mark O'Brien commonly perform?
Top Medicare-reported procedures in 2023: Subsequent hospital care with moderate levelof medical decision making (HCPCS 99233); Hospital discharge day management (HCPCS 99239); Subsequent hospital care with moderate levelof medical decision making (HCPCS 99232). Source: CMS Medicare Physician & Other Practitioners file.