MARK C. JOHNSON MD – NPI #1013923127
Internal Medicine

A physician who provides long-term, comprehensive care in the office and the hospital, managing both common and complex illness of adolescents, adults and the elderly. Internists are trained in the diagnosis and treatment of cancer, infections and diseases affecting the heart, blood, kidneys, joints and digestive, respiratory and vascular systems. They are also trained in the essentials of primary care internal medicine, which incorporates an understanding of disease prevention, wellness, substance abuse, mental health and effective treatment of common problems of the eyes, ears, skin, nervous system and reproductive organs.

Health Care Provider Taxonomy Code for Internal Medicine

MARK JOHNSON is a physician located in MASON CITY, IA. NPPES has assigned the NPI number 1013923127 to MARK JOHNSON on July 31, 2006. It is a Type-1 NPI, indicating this NPI number is associated with an individual. The primary taxonomy selected by this provider is 207R00000X from the Health Care Provider Taxonomy code set, which is classified as Internal Medicine.

The NPI profile was last updated on Jul 08, 2025. Use the NPI data found here to bill health insurance companies, identify providers enrolled in Medicare and Medicaid services or other HIPAA compliant transactions. See the complete NPI profile for MARK JOHNSON below.

NPI Profile for
MARK C. JOHNSON

NPI Number
1013923127
Enumeration Date

(about 20 years ago)
Entity Type
Type-1  Individual (Male)
Legal Name
MARK C. JOHNSON
Credentials
MD
Primary location
910 N EISENHOWER AVE
MASON CITY, IA 50401-2800
Phone: (641) 428-7799 Fax: (641) 428-5274
Mailing address
621 S ILLINOIS AVE
SUITE 103
MASON CITY, IA 50401-5489
Phone: (641) 428-3041 Fax: (641) 428-3059
Sole Proprietor
No
Updated
Certification Date
Jul 08, 2025

Note: NPPES allows providers to attest to the accuracy of their NPI data. When a provider request any change to the NPI record, they will be able to attest to their changed NPI data, resulting in an updated certification date.

Taxonomy Code(s)

A taxonomy code is a code that describes the health care service provider's type, classification, and the area of specialization. The primary specialty for this provider is indicated as (Primary) below.

Taxonomy Classification / Specialization State License
207R00000X
- Internal Medicine (Primary)		 IA 21527

The taxonomy codes are selected by the provider at the time of NPI registration. Selection of a taxonomy code does not replace any credentialing or validation process that the provider requesting the code should complete.

Endpoint

Health Information Exchange (HEI)

HEI is the mobilization of health care information electronically across organizations within a region, community or hospital system. Endpoints provide a simple and secure way for participants to send authenticated, encrypted health information directly to known, trusted recipients over the internet such as primary care physicians, specialists, hospitals, labs, etc.

Endpoint
[email protected]
Endpoint type
Direct Messaging Address
Endpoint Description
MERCYONE NORTH IOWA DIRECT EMAIL
Content Type
OTHER
Affiliation
N
Endpoint Location
910 N EISENHOWER AVE,
MASON CITY, IA 77025-1669

Additional Information

Education
UNIVERSITY OF IOWA, RJ & L CARVER COLLEGE OF MEDICINE - Graduated 1977
Accepts Medicare
This provider accepts Medicare-approved amount as payment in full. The Medicare-approved amount is the total the provider can be paid. When a provider accepts the Medicare-approved amount as payment, you won't be billed for more than the Medicare deductible & coinsureance.
Medicare Ordering & Referring
Provider can:
  • Refer to Part B
  • Order Durable Medical Equipment
  • Refer to Home Health Agency
  • Order Power Mobility Devices
Affiliations
MARK JOHNSON is affiliated with the following medical group(s):
  • HOSPITAL
    • FRANKLIN GENERAL HOSPITAL
      1720 CENTRAL AVENUE EAST
      HAMPTON, IA 50441
    • HANCOCK COUNTY HEALTH SYSTEM
      532 1ST ST NW
      BRITT, IA 50423
    • MERCYONE NORTH IOWA MEDICAL CENTER
      1000 FOURTH STREET SW
      MASON CITY, IA 50401

Why is my NPI data (personal information) being displayed publicly?
If you have an active NPI profile, your profile is required to be disclosed according to the FOIA and eFOIA. HIPAA also requires covered providers to share their NPI with other providers, health plans, clearinghouses and any entity that may need it for billing purposes.

How do I correct or change the NPI data displayed here?
At any time, providers can make changes to their NPI profile at NPPES. Login to NPPES to make changes online or call (800) 465-3203 for assistance. Changes made at NPPES will be reflected on this web site within a few days.

Can I hide my NPI profile from the public?
Unfortunately, No. The NPPES discloses health care provider data under the Freedom of Information Act to the public, which means anyone may request such information directly from the National Plan & Provider Enumeration System. See the complete CMS Data Dissemination Notice here.