William P. Klein, MD

NPI 1205834819ActiveIndividual· Internal Medicine· Newport Beach, CA

Internal Medicine (MD) in Newport Beach, California, trained at State University of New York Downstate Medical Center (class of 1966). Their prescriptions cost Medicare Part D more than their services did: $827,697 for 5,915 claims, against $164,763 paid for services in 2024. Genzyme Corporation was the largest of 22 companies reporting payments in 2025, $1,896 in all, mostly food and beverage.

Overview

NPI	1205834819
Status	Active
Entity type	Individual
Credential	MD
Sole proprietor	No
NPI issued	Jul 8, 2005
Last updated in NPPES	Jan 17, 2008

Specialties and licenses

Taxonomy	Code	License	State
Internal Medicine Primary	207R00000X	G14712	CA

About license numbers in NPPES

Exclusion screening

List	Result	Details
HHS-OIG LEIE · Nov 10, 2026	No match	Checked by NPI and by name + state
North Carolina Medicaid · Nov 11, 2026	No match	—
New York OMIG · Nov 11, 2026	No match	—
Ohio Medicaid · Nov 11, 2026	No match	—
Pennsylvania Medicheck · Nov 11, 2026	No match	—
Washington HCA · Nov 11, 2026	No match	—

Official OIG search · How matching works ·Bulk check a roster

Medicare

Enrollment (PECOS)	Enrolled Practitioner - Internal Medicine (CA)
Accepts assignment	Yes (participating)

Medicare services in 2024

Medicare patients	350
Services billed	1,522 across 15 procedure codes
Paid by Medicare	$164,763

Part D prescriptions in 2024

Prescriptions (claims)	5,915 · 13,277 30-day fills
Patients	455
Total drug cost	$827,697
Generic share	85% of claims

Medicare sources and data years

Education and affiliations

Medical school	State University of New York Downstate Medical Center
Graduation year	1966
Medicare specialty	Internal Medicine
Secondary specialties	Pulmonary Disease