Doctor profile · Federal record

Dr. William Parker, MD

Emergency Medicine Physician (CMS: Emergency Medicine) · Mason City, IA

  • NPI 1356459903
  • Accepts Medicare
  • 35 yrs in practice
  • Male
  • Group practice
  • No sanctions

Practice & contact

NPPES Updated May 11, 2026
Primary practice
1000 4Th St Sw, Suite ER
Mason City, IA 504012800
(641) 422-7234
fax (641) 422-6373
Mailing address
621 S Illinois Ave, Suite 103
Mason City, IA 504015489

Credentials & registration

NPPES · NUCC
NPI registered
August 2006 — 20 yrs on file
Profile last updated
October 11, 2023
Year of graduation
1991 — 35 yrs since
Specialty taxonomy
207P00000X — NUCC code
State license (1)
Iowa #28723
Medicaid
IA #2073189

Federal sanctions & exclusions

OIG LEIE Updated May 11, 2026

No sanctions, exclusions or revocations on file

Checked against OIG LEIE on NPI 1356459903. Last verified May 11, 2026.

Medicare procedures · 2023

Top services delivered

CMS Provider Utilization
Total services
339
Distinct HCPCS
3
Medicare allowed
$45,037
HCPCS Description Services Patients Avg allowed
99285 Emergency department visit with high level of medical decision making 195 190 $164
99284 Emergency department visit with moderate level of medical decision making 77 75 $113
99283 Emergency department visit with low level of medical decision making 67 64 $67

In context: peer comparison

Among 4 peers in Mason City Emergency Medicine Physician, average services per provider: 95. This provider delivers 3.6× the peer median.

Open Payments

Industry payments received

CMS Open Payments
All-time total
$189
Transactions
2
Manufacturers
2
Payer (manufacturer) Industry Txns Amount
Boston Scientific Corporation 1 $155.07
Abbott Laboratories 1 $33.50

By nature of payment

Food and Beverage
$189

Medicare Part D · 2023

Top prescriptions

CMS Part D Prescriber
Total claims
135
Patients
132
Total drug cost
$1,140
Drug Type Claims Patients Total cost
Prednisone Generic 19 18 $58
Doxycycline Monohydrate Generic 18 17 $289
Azithromycin Generic 16 16 $102
Hydrocodone-Acetaminophen (Hydrocodone/Acetaminophen) Brand 16 16 $98
Cefdinir Generic 15 14 $271
Tramadol Hcl Generic 14 14 $32
Levofloxacin Generic 13 13 $83
Ciprofloxacin Hcl Generic 12 12 $77
Methylprednisolone Generic 12 12 $131

Hospital affiliations

CMS Hospital Compare

Frequently asked questions

Auto-generated from federal data
What is Dr. William Parker's medical specialty?
Dr. William Parker practices Emergency Medicine Physician in Mason City, IA.
Where does Dr. William Parker practice?
Dr. William Parker practices at 1000 4Th St Sw, Mason City, IA 504012800. Office phone: 6414227234.
What is Dr. William Parker's NPI?
Dr. William Parker's National Provider Identifier (NPI) is 1356459903, issued by NPPES.
Does Dr. William Parker accept Medicare assignment?
Yes. Dr. William Parker accepts Medicare assignment, meaning Medicare-allowed amounts are accepted as full payment for covered services.
What procedures does Dr. William Parker commonly perform?
Top Medicare-reported procedures in 2023: Emergency department visit with high level of medical decision making (HCPCS 99285); Emergency department visit with moderate level of medical decision making (HCPCS 99284); Emergency department visit with low level of medical decision making (HCPCS 99283). Source: CMS Medicare Physician & Other Practitioners file.