Doctor profile · Federal record
Dr. William Riesen, MD
Internal Medicine Physician (CMS: Internal Medicine) · Mason City, IA
- NPI 1548377997
- Accepts Medicare
- 33 yrs in practice
- Male
- Group practice
- No sanctions
Practice & contact
- Primary practice
-
1010 4Th St Sw Ste 305
Mason City, IA 504012801
(641) 428-5700
fax (641) 428-2515 - Mailing address
-
621 S Illinois Ave, Suite 103
Mason City, IA 504015489
Credentials & registration
- NPI registered
- August 2006 — 20 yrs on file
- Profile last updated
- July 14, 2025
- Year of graduation
- 1993 — 33 yrs since
- Specialty taxonomy
- 207R00000X — NUCC code
- State license (1)
- Iowa #31260
- Medicaid
- IA #4137984
Federal sanctions & exclusions
No sanctions, exclusions or revocations on file
Checked against OIG LEIE on NPI 1548377997. Last verified May 11, 2026.Medicare procedures · 2023
Top services delivered
Total services
3,246
Distinct HCPCS
9
Medicare allowed
$154,019
| HCPCS | Description | Services | Patients | Avg allowed | |
|---|---|---|---|---|---|
93010 |
Routine electrocardiogram (ecg) using at least 12 leads with interpretation and report only | 1,406 | 1,092 | $8 | |
99213 |
Established patient office or other outpatient visit, 20-29 minutes | 875 | 412 | $62 | |
99214 |
Established patient office or other outpatient visit, 30-39 minutes | 468 | 304 | $91 | |
99232 |
Subsequent hospital care with moderate levelof medical decision making, if using time, at least 35 minutes | 216 | 64 | $73 | |
G0439 |
Annual wellness visit, includes a personalized prevention plan of service (pps), subsequent visit | 186 | 186 | $120 | |
99238 |
Hospital discharge day management, 30 minutes or less | 56 | 50 | $75 | |
99223 |
Initial hospital care with moderate level of medical decision making, if using time, at least 75 minutes | 15 | 15 | $162 | |
99204 |
New patient office or other outpatient visit, 45-59 minutes | 13 | 13 | $124 | |
99212 |
Established patient office or other outpatient visit, 10-19 minutes | 11 | 11 | $33 |
In context: peer comparison
Among 7 peers in Mason City Internal Medicine Physician, average services per provider: 221. This provider delivers 15× the peer median.Medicare Part D · 2023
Top prescriptions
Total claims
3,142
Patients
805
Total drug cost
$158,873
| Drug | Type | Claims | Patients | Total cost |
|---|---|---|---|---|
| Atorvastatin Calcium | Generic | 428 | 127 | $6,158 |
| Omeprazole | Generic | 298 | 72 | $3,981 |
| Levothyroxine Sodium | Generic | 279 | 76 | $3,683 |
| Lisinopril | Generic | 254 | 67 | $2,157 |
| Losartan Potassium | Generic | 234 | 67 | $3,022 |
| Metoprolol Succinate | Generic | 217 | 60 | $3,989 |
| Eliquis (Apixaban) | Brand | 203 | 27 | $122,997 |
| Gabapentin | Generic | 200 | 48 | $3,434 |
| Amlodipine Besylate | Generic | 198 | 43 | $1,287 |
| Hydrochlorothiazide | Generic | 160 | 47 | $1,242 |
Frequently asked questions
What is Dr. William Riesen's medical specialty?
Dr. William Riesen practices Internal Medicine Physician in Mason City, IA.
Where does Dr. William Riesen practice?
Dr. William Riesen practices at 1010 4Th St Sw Ste 305, Mason City, IA 504012801. Office phone: 6414285700.
What is Dr. William Riesen's NPI?
Dr. William Riesen's National Provider Identifier (NPI) is 1548377997, issued by NPPES.
Does Dr. William Riesen accept Medicare assignment?
Yes. Dr. William Riesen accepts Medicare assignment, meaning Medicare-allowed amounts are accepted as full payment for covered services.
What procedures does Dr. William Riesen commonly perform?
Top Medicare-reported procedures in 2023: Routine electrocardiogram (ecg) using at least 12 leads with interpretation and report only (HCPCS 93010); Established patient office or other outpatient visit (HCPCS 99213); Established patient office or other outpatient visit (HCPCS 99214). Source: CMS Medicare Physician & Other Practitioners file.