WILLIAM D WALLACE DO
NPI 1104387398
Internal Medicine - Pulmonary Disease in Cleveland, OH

Q: What is the provider's specialty?

The provider's specialty is Internal Medicine with taxonomy code 207RP1001X and a focus in Pulmonary Disease.

NPI Status: Active since March 29, 2019

Contact Information

9500 EUCLID AVE # NA-23
CLEVELAND, OH
ZIP 44195
Phone: (216) 444-2200

Recently Updated NPI Information
Some details in this NPI profile have been updated in the NPI registry within the last 30 days.

NPPES record last updated: June 26, 2026. Verified against the NPPES registry weekly; last sync: July 12, 2026.

Table of Contents

NPI Profile Information
Primary Taxonomy
Secondary Taxonomies
NPI Validation
Other Providers Same Location
Frequently Asked Questions

Individual
Male
Internal Medicine
Pulmonary Disease

About WILLIAM WALLACE

This page provides the complete NPI Profile along with additional information for William Wallace, an internist established in Cleveland, Ohio with a medical specialization in Internal Medicine, focusing in pulmonary disease . The healthcare provider is registered in the NPI registry with number 1104387398 assigned on March 2019. The practitioner's primary taxonomy code is 207RP1001X with license number 34.015784 (OH). The provider is registered as an individual and his NPI record was last updated June 2026.

NPI: 1104387398
Provider Name: WILLIAM D WALLACE DO
Gender: Male
Entity Type: Individual
Location Address: 9500 EUCLID AVE # NA-23 CLEVELAND, OH 44195
Location Phone: (216) 444-2200
Mailing Address: 9500 EUCLID AVE # NA-23 CLEVELAND, OH 44195
Is Sole Proprietor?: Yes
Enumeration Date: 03-29-2019
Last Update Date: 06-26-2026
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An internist like William Wallace is a physician who has completed an internal medicine residency and is board-certified or board-eligible in an internist specialty. Internists are trained to care for adults of all ages for many different medical conditions. An internist typically monitors chronic physical conditions, identifies acute diseases, provides family planning, provides counseling about wellness and disease prevention, etc.

Location Map

Specialty - Primary Taxonomy

The NPI enumerator requires providers to submit at least one taxonomy code. A taxonomy code is a unique 10-character code that describes the healthcare provider type, classification, and the area of specialization. There could be only one primary taxonomy code per NPI record. For individual NPIs the license data is associated to the taxonomy code.

Classification: Internal Medicine Pulmonary Disease
Taxonomy Code: 207RP1001X
Type: Allopathic & Osteopathic Physicians
License No.: 34.015784
License State: OH
Taxonomy Description: An internist who treats diseases of the lungs and airways. The pulmonologist diagnoses and treats cancer, pneumonia, pleurisy, asthma, occupational and environmental diseases, bronchitis, sleep disorders, emphysema and other complex disorders of the lungs.

Secondary Taxonomies

The provider has reported to the NPI enumerator additional taxonomy codes. Multiple taxonomy codes may represent subspecialties or other areas of specialization the provider maybe licensed to practice.

No.	Taxonomy Code	Type	Classification / Specialization	License No. (State)
1	207RC0200X	Allopathic & Osteopathic Physicians	Internal Medicine Critical Care Medicine	34.015784 (OH)

NPI Number Validation

How NPI Validation Works

The NPI validation process uses the ISO-standard Luhn algorithm, a mathematical "handshake", to ensure that a provider's 10-digit ID is authentic and free of common typing errors.

To verify the NPI 1104387398, we treat the final digit (8) as the Check Digit—the target answer we need to reach. The process begins by taking the first nine digits and adding a constant value of 24, which accounts for the "80840" prefix required for all U.S. health identifiers. We then double every other digit starting from the right and sum the individual digits of those results together. For this specific NPI, that total comes to 62. The final step is to find the difference between that total and the next multiple of ten (70 - 62 = 8).

Digit-by-digit view

Use the first nine digits for the calculation. Starting from the right, double every other digit. The last digit is the check digit and is not part of the calculation.

Pos 1

Doubled → 2

Pos 2

Unchanged

Pos 3

Doubled → 0

Pos 4

Unchanged

Pos 5

Doubled → 6

Pos 6

Unchanged

Pos 7

Doubled → 14 → 1 + 4

Pos 8

Unchanged

Pos 9

Doubled → 18 → 1 + 8

Check

Target digit

Regular digit Doubled digit Check digit

Step 1: Double every other digit from the right

Starting with the rightmost digit of the first nine digits, double every other value. If doubling creates a two-digit number, add those digits together.

1 → 2 0 → 0 3 → 6 7 → 14 → 5 9 → 18 → 9

Step 2: Add all digits plus the NPI constant

Add the transformed values, the unchanged digits, and the constant 24.

2 + 1 + 0 + 4 + 6 + 8 + 1 + 4 + 3 + 1 + 8 + 24 = 62

Step 3: Find the amount needed to reach the next multiple of 10

The next multiple of ten after 62 is 70. The difference is the calculated check digit.

70 - 62 = 8

This NPI is valid

The calculated check digit is 8, which matches the last digit of 1104387398.