Provider records sourced from NPPES (CMS National Plan & Provider Enumeration System). Data current as of October 4, 2026.
NPIDirectory

Dr. Mark E Lassise, MD

Individual provider Psychiatry Physician · NPI 1023002508

Dr. Mark E Lassise, MD practises Psychiatry in Mason City, Iowa. Graduated from University of Colorado School of Medicine, Denver in 1980, 46 years ago. Practices with North Iowa Mercy Clinics, a 300-clinician group, accepts Medicare assignment and offers telehealth. Licensed in Iowa.

Years since qualifying
46
Trained at
University of Colorado School of Medicine, Denver
Licensed in
IA
In the registry since
2005
What do these letters mean?
MD — Doctor of Medicine
A physician who completed allopathic medical school.

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Practice location Address checks out

250 S Crescent Dr Ste 10
Mason City, IA 50401-2926
Phone: (641) 494-5170
Fax: (641) 494-5175
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Pin is approximate — placed at the ZIP-code centre, not the exact door.

Specialties & licences

Psychiatry Physician (primary) Taxonomy 2084P0800X · Licence 22919 (IA)

Record details

NPI number1023002508
Entity typeIndividual (Type 1)
GenderMale
Credentials MD
Sole proprietorNo
NPI enumeratedSeptember 9, 2005
Last updated in NPPESJuly 6, 2020
Certification dateJuly 6, 2020

Medicare enrollment

From the CMS Doctors & Clinicians file — this clinician is enrolled in Medicare.

Medicare specialtyPSYCHIATRY
Medical schoolUNIVERSITY OF COLORADO SCHOOL OF MEDICINE, DENVER
Graduated 1980 (46 years in practice)
Group practice North Iowa Mercy Clinics — 300 clinicians
Accepts Medicare assignment Yes — accepts the Medicare-approved amount
TelehealthOffers telehealth services
Practice locations4 on file with Medicare

Medicare patients and services, 2024

From the CMS Medicare Physician & Other Practitioners file for calendar year 2024. It counts Original Medicare patients only, so a practice that mostly sees Medicare Advantage or privately insured patients looks smaller here than it is.

Medicare patients120
Services billed 922 a service is one billed item, such as a visit, a test or a procedure
Average patient age76

Dollar amounts are not shown. What Medicare pays a practice is gross billings, before staff, premises and tax and including the cost of any drugs it administers, so it is not what a clinician earns.

Payments from drug and device companies, 2025

Drug and device makers are required by federal law (the Physician Payments Sunshine Act) to report what they pay or give to clinicians, and CMS publishes the reports as Open Payments. This is the 2025 program year. A report is a record of a payment, not an allegation of anything, and many are small items such as meals. Only general payments are listed here; research payments and ownership or investment interests are reported separately by CMS and are not shown.

Food and Beverage $998 50 payments · a meal or drink at a meeting or visit, not a fee

Each amount is the sum of what companies reported for that kind of payment in 2025, rounded to the dollar. Not all of it is income to the clinician: a meal is not a fee, a charitable contribution goes to a charity, and a royalty or an acquisition payment is not a salary.

Check a report, or dispute one, at the source in CMS’s own tool, Open Payments. Corrections go through CMS’s dispute process. This site removes a home address on request and asks for no proof, because that is privacy; it will not remove an accurate payment report on request, because that is a statutory public disclosure.

Practises at

Facilities the CMS Facility Affiliation file lists for this clinician. Those with a page here are linked.

Colleagues at North Iowa Mercy Clinics

Clinicians the CMS Doctors & Clinicians file lists under the same group practice. CMS counts 300 clinicians in the practice; 12 are shown here.

Other providers in Mason City