Type 1 · Individual ✓ Active NPI ✓ Valid NPI checksum

Dr. Christopher G Tretter, MD

Hematology & Oncology Physician in South Portland, ME · enumerated 2006.

Data current as of Jul 13, 2026 · sourced from CMS NPPES

National Provider Identifier

1083648133

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Registry record

Entity type Individual (Type 1)

Name Dr. Christopher G Tretter

Credential MD

Sex Male

Practice address Mainehealth Cancer Care, 265 Western Ave Suite 2, South Portland, ME, 04106

Phone (207) 661-0200

Enumeration date Jul 11, 2006

Last updated in NPPES Nov 15, 2023

Taxonomy & licenses

207RH0003X Hematology & Oncology Physician Allopathic & Osteopathic Physicians · License 234273 (MA) Secondary

207RH0003X Hematology & Oncology Physician Allopathic & Osteopathic Physicians · License 27471 (ME) Primary

MD · Doctor of Medicine: A physician who completed medical school (allopathic medicine), residency training, and state licensure. About the MD credential

Other identifiers

Identifier	Type	State	Issuer
30200880	Medicaid	NH	-
110077681A	Medicaid	MA	-

What is an NPI number?

A National Provider Identifier (NPI) is a unique 10-digit number that CMS assigns to every U.S. healthcare provider and organization under HIPAA. Type 1 NPIs identify individual providers; Type 2 NPIs identify organizations. The NPI appears on insurance claims, prescriptions, and credentialing paperwork, and never changes, even if the provider moves or changes specialty.

Read the full guide → Validate an NPI →

Frequently asked questions

Is NPI 1083648133 active?

Yes, as of the latest NPPES snapshot, NPI 1083648133 is active (record last updated 2023-11-15).

How do I verify Christopher Tretter's NPI record?

Cross-check NPI 1083648133 against the official CMS registry at npiregistry.cms.hhs.gov. This page mirrors the same public NPPES data with a monthly snapshot.

Source: CMS NPPES (public data). Snapshot 2026-07-13. Provider record last updated 2023-11-15.