- Update your location to get information specific to your area.
  
  Enter a ZIP code or city and state
  
  near_me Use my current location

Site Logo

Health care

We provide affordable and personalized care

Find care
Find doctors, specialists, locations, urgent care and other services near you
Patient portal sign-in
Make appointments, get medical records, message your care team and more
Get the right kind of care
From primary to virtual to urgent care, learn where to go and when

Understanding coughs: Types, causes and treatments

More articles

Financial

Accounts to help you save and pay for health care expenses

Sign in to your account
Manage your HSA, check your balance, transfer a balance and more
Explore account types
Compare health benefit accounts and learn how each option can work for you
Pay a bill
The fast, easy way to pay your medical bills online

Open enrollment

Tax season resources

Get ready for HSA tax season

If you used an HSA this year, the HSA Tax Center offers general information about contributions, eligible expenses and commonly used tax forms — all in one place.

Visit the HSA Tax Center

Pharmacy

We make it easy to get medications you need, when and where you need them

Home Delivery Pharmacy
Register or sign in, fill your prescription and have it delivered right to your door
Specialty Pharmacy
Register or sign in and fill your specialty prescriptions for complex therapies
Infusion Pharmacy
Register or sign in and manage your infusion therapies
Frontier Therapies
Manage your medications for rare disease
divvyDOSE
Enroll to get medications pre-sorted by day and time and delivered to your home
Genoa Healthcare
Manage your medications for mental health and complex conditions

Optum Rx
For people with pharmacy insurance benefits through Optum Rx
Track orders
Track your home delivery and specialty order
Pharmacy support
Find contact information and answers to frequently asked questions

Mobile app

Optum Rx on the go

Request refills, track order status, manage billing information and much more.

Johannes Karl Martensson, MD

*Please contact clinic directly to confirm appointment availability.

*Please contact clinic directly to confirm appointment availability.

Specialty

Gastroenterology

Languages

Norwegian, Swedish, German,English

Schedule virtual care

Seeing patients at

Citrus Gastroenterology PA

1-352-344-8080

-- miles away

3653 E Forest Dr, Inverness, FL 34453

Please contact the clinic directly to schedule and confirm appointment availability.

Gender

Male

Board certifications

American Board of Internal Medicine

Licenses

FL, ME71187

Employed or contracted

Contracted

Network Name

Optum Florida

PCP ID

44201

NPI

1417954298

Hospital affiliations

Citrus Memorial Hospital
Medical School
- University of Linkoping College of Medicine
Residency
- Greenwich Hospital Association
  
  Internal Medicine
Fellowship
- Thomas Jefferson University Hospital
  
  Internal Medicine

back to top

We use cookies and similar tools to make your use of this website easy and to keep it working properly. We may share data about you and how you use the site with third parties, such as analytics and marketing partners. Learn more in our Privacy Policy and Terms of Use. By continuing to use the site, you agree to this.