DR. GARY HAGAN O.D.
NPI 1124184502
Optometrist in San Leandro, CA

NPI Status: Active since December 29, 2006

Contact Information

1900 DAVIS ST
SAN LEANDRO, CA
ZIP 94577
Phone: (510) 632-5210

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

Individual
Male
Optometrist

About GARY HAGAN

This page provides the complete NPI Profile along with additional information for Gary Hagan, a provider established in San Leandro, California with a medical specialization in Optometrist. The healthcare provider is registered in the NPI registry with number 1124184502 assigned on December 2006. The practitioner's primary taxonomy code is 152W00000X with license number 7697T (CA). The provider is registered as an individual and his NPI record was last updated 14 years ago.

NPI: 1124184502
Provider Name: DR. GARY HAGAN O.D.
Gender: Male
Entity Type: Individual
Location Address: 1900 DAVIS ST SAN LEANDRO, CA 94577
Location Phone: (510) 632-5210
Mailing Address: 1900 DAVIS ST SAN LEANDRO, CA 94577
Mailing Phone: (510) 632-5210
Is Sole Proprietor?: Yes
Enumeration Date: 12-29-2006
Last Update Date: 08-02-2012
Code Navigator

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: Optometrist
Taxonomy Code: 152W00000X
Type: Eye and Vision Services Providers
License No.: 7697T
License State: CA
Taxonomy Description: Doctors of optometry (ODs) are the primary health care professionals for the eye. Optometrists examine, diagnose, treat, and manage diseases, injuries, and disorders of the visual system, the eye, and associated structures as well as identify related systemic conditions affecting the eye. An optometrist has completed pre-professional undergraduate education in a college or university and four years of professional education at a college of optometry, leading to the doctor of optometry (O.D.) degree. Some optometrists complete an optional residency in a specific area of practice. Optometrists are eye health care professionals state-licensed to diagnose and treat diseases and disorders of the eye and visual system.

NPI 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 1124184502, we treat the final digit (2) 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 58. The final step is to find the difference between that total and the next multiple of ten (60 - 58 = 2).

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 → 4

Pos 4

Unchanged

Pos 5

Doubled → 2

Pos 6

Unchanged

Pos 7

Doubled → 8

Pos 8

Unchanged

Pos 9

Doubled → 0

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 2 → 4 1 → 2 4 → 8 0 → 0

Step 2: Add all digits plus the NPI constant

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

2 + 1 + 4 + 4 + 2 + 8 + 8 + 5 + 0 + 24 = 58

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

The next multiple of ten after 58 is 60. The difference is the calculated check digit.

60 - 58 = 2

This NPI is valid

The calculated check digit is 2, which matches the last digit of 1124184502.