Provider records sourced from NPPES (CMS National Plan & Provider Enumeration System). Data current as of August 10, 2026.
NPIDirectory

Mark H Johnston, MD

Individual provider Gastroenterology Physician · NPI 1003898131

Mark H Johnston, MD is a Gastroenterology in Lancaster, Pennsylvania. Graduated from Hahnemann University College of Medicine in 1985, 41 years ago. Practices with Regional Gastroenterology Associates of Lancaster, Ltd, a 251-clinician group and accepts Medicare assignment. Licensed in Pennsylvania.

Years since qualifying
41
Trained at
Hahnemann University College of Medicine
Licensed in
PA
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

2112 Harrisburg Pike Ste 202
Lancaster, PA 17601-2644
Phone: (717) 544-3500
Fax: (717) 544-3501
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Pin is approximate — placed at the ZIP-code centre, not the exact door.

Specialties & licences

Gastroenterology Physician (primary) Taxonomy 207RG0100X · Licence MD425522 (PA)

Record details

NPI number1003898131
Entity typeIndividual (Type 1)
GenderMale
Credentials MD
Sole proprietorNo
NPI enumeratedNovember 15, 2005
Last updated in NPPESJune 13, 2019
Mailing address2112 Harrisburg Pike Ste 202, Lancaster, PA 17601-2644

Medicare enrollment

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

Medicare specialtyGASTROENTEROLOGY
Medical schoolHAHNEMANN UNIVERSITY COLLEGE OF MEDICINE
Graduated 1985 (41 years in practice)
Group practice Regional Gastroenterology Associates Of Lancaster, Ltd. — 251 clinicians
Accepts Medicare assignment Yes — accepts the Medicare-approved amount
Practice locations2 on file with Medicare

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