KATHERINE MADISON MACMILLAN M.D.
NPI 1780117416
Internal Medicine - Gastroenterology in Simpsonville, SC

NPI Status: Active since April 10, 2017

Contact Information

741 SE MAIN ST
SIMPSONVILLE, SC
ZIP 29681
Phone: (864) 522-8420
Fax: (864) 522-8425

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  • Individual
  • Female
  • Years of Experience 9
  • Internal Medicine
  • Gastroenterology
  • Accepts Medicare Approved Payment
  • PECOS Enrolled

About KATHERINE MACMILLAN

This page provides the complete NPI Profile along with additional information for Katherine Macmillan, an internist established in Simpsonville, South Carolina with a medical specialization in Internal Medicine, focusing in gastroenterology and more than 9 years of experience. The healthcare provider is registered in the NPI registry with number 1780117416 assigned on April 2017. The practitioner's primary taxonomy code is 207RG0100X with license number 85580 (SC). The provider is registered as an individual and her NPI record was last updated February 2026.

NPI
1780117416
Provider Name
KATHERINE MADISON MACMILLAN M.D.
Gender
Female
Entity Type
Individual
Location Address
741 SE MAIN ST SIMPSONVILLE, SC 29681
Location Phone
(864) 522-8420
Location Fax
(864) 522-8425
Mailing Address
300 E MCBEE AVE STE 300 GREENVILLE, SC 29601
Mailing Phone
(864) 522-8603
Medical School Name
OTHER
Graduation Year
2017
Is Sole Proprietor?
No
Enumeration Date
04-10-2017
Last Update Date
02-23-2026
Code Navigator

An internist like Katherine Macmillan 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

Secondary Locations

  • 13400 E Shea Blvd
    Scottsdale, AZ 85259
    (480) 301-8000
  • 727 SE Main St Ste 340
    Simpsonville, SC 29681
    (864) 455-2888

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 Gastroenterology

Taxonomy Code
207RG0100X
Type
Allopathic & Osteopathic Physicians
License No.
85580
License State
SC
Taxonomy Description
An internist who specializes in diagnosis and treatment of diseases of the digestive organs including the stomach, bowels, liver and gallbladder. This specialist treats conditions such as abdominal pain, ulcers, diarrhea, cancer and jaundice and performs complex diagnostic and therapeutic procedures using endoscopes to visualize internal organs.

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)
1207R00000XAllopathic & Osteopathic Physicians

Internal Medicine

85580 (SC)
2207R00000XAllopathic & Osteopathic Physicians

Internal Medicine

009641 (GA)
3207RG0100XAllopathic & Osteopathic Physicians

Internal Medicine
Gastroenterology

72379 (AZ)

Medicare Participation & PECOS Enrollment Status

Katherine Macmillan is registered with Medicare and accepts claims assignment, this means the provider accepts the approved amount for the cost of rendered services as full payment. Participating providers may not charge beneficiaries more than the approved amount for their services. Please keep in mind that beneficiaries still have to pay a coinsurance or copayment amount for a visit or service.

Katherine Macmillan is enrolled in PECOS and is eligible to order or refer health care services for Medicare patients. The provider is eligible to order or refer: Part B Clinical Laboratory and Imaging, Durable Medical Equipment (DME), a Home Health Agency (HHA) and Power Mobility Devices.

What is PECOS?
PECOS is the online Medicare enrollment management system or Provider, Enrollment, Chain and Ownership System. The PECOS system is a database of providers who have registered with CMS as providers or suppliers. PECOS is the primary source of information about verified Medicare professionals. Providers that want to participate in this program need to enroll in PECOS with their NPI number to avoid denied claims.

  • Is the provider registered in PECOS? Yes

  • PECOS PAC ID: 8426312141

    What is the PECOS Associate Control ID?
    A PAC ID is a unique 10-digit number assigned to an individual or organization healthcare provider in PECOS. The PAC ID is used to link together all the provider information, like tax identification numbers and organizational names. A PAC ID can be connected to multiple Enrollment IDs if an individual or organization has enrolled in PECOS more than once.

  • PECOS Enrollment ID: I20250616002806

    What is the Provider Enrollment ID?
    The Enrollment ID is a unique alphanumeric 15-digit code assigned to each new provider's PECOS enrollment application. The Enrollment ID is used to link together all the provider enrollment information like enrollment type, state, provider specialty, and reassignment of benefits.

  • Accepts Medicare Assignment? Yes

    What does it mean "accepts medicare assignment"?
    When a provider accepts Medicare assignment, the provider agrees to be paid directly by Medicare and to accept the payment amount approved by Medicare. Additionally, the provider agrees to not bill patients for more than the Medicare deductible and coinsurance amounts.
    A provider who doesn't accept assignment may charge you up to 15% over the Medicare-approved amount. This is known as the limiting charge. You may have to pay this amount, or it may be covered by another insurer.

  • Eligible to Order or Refer Part B Clinical Laboratory and Imaging: Yes

  • Eligible to Order or Refer Durable Medical Equipment (DMEPOS): Yes

  • Eligible to Order or Refer a Home Health Agency (HHA): Yes

  • Eligible to Order or Refer Power Mobility Devices: Yes

Physician Visit Costs



The typical physician office visit costs for Medicare beneficiaries in this area are: $31.01 for a new patient copayment and $23.78 for an established patient copayment.

The pricing information below displays the copayment minimum, maximum and average amount that patients under Medicare are charged when visiting this provider as a new or established patient. Please keep in mind that these prices are just for reference purposes, and the actual prices charged by the provider might be different.

For patients covered under private health plans the prices below are also useful as healthcare pricing for private insurance is usually established as a function of Medicare prices. Private insurance covered patients should check their individual plans to determine the exact pricing.

The prices below reflect the costs for new and established patients in the 29681 ZIP code area.

New Patients Visit Costs *

The most utilized procedure code for new patients office visits is 99204

  • Average New Patient Price $124.04
  • Minimum New Patient Price $53.57
  • Maximum New Patient Price $163.84
  • Average New Patient Copayment $31.01
  • Minimum New Patient Copayment $13.39
  • Maximum New Patient Copayment $40.96

Established Patients Visit Costs *

The most utilized procedure code for established patients office visits is 99214

  • Average Established Patient Price $95.12
  • Minimum Established Patient Price $16.96
  • Maximum Established Patient Price $133.52
  • Average Established Patient Copayment $23.78
  • Minimum Established Patient Copayment $4.24
  • Maximum Established Patient Copayment $33.38

* The physician office visit costs information is generated by statistical analysis of similar providers in the same geographical area. The pricing information above IS NOT the amount charged by this provider.

Find Provider Hospital Affiliations - Privileges

Doctors and physicians must apply for hospital privileges to treat patients at hospitals. Find out if your doctor has privileges to practice at your preferred hospital by using the hospital affiliation information below based on recent medical claims.

Hospital affiliation is identified through self-reporting data, inpatient, outpatient, physician and ancillary service claims linked by the medical claims NPI number and place of service code. Additionally, to further determine provider hospital affiliation the clinician must have provided services to at least three patients on three different dates in the last 12 months. Katherine Macmillan is affiliated with the following medical facilities:

Hospital Name Address Phone Hospital Type Overall Rating
PRISMA HEALTH BAPTIST EASLEY HOSPITAL200 FLEETWOOD DRIVE
EASLEY, SC 29640
(864) 442-7606Acute Care Hospitals
PRISMA HEALTH HILLCREST HOSPITAL741 SOUTH EAST MAIN STREET
SIMPSONVILLE, SC 29681
(864) 454-6100Acute Care Hospitals
PRISMA HEALTH GREENVILLE MEMORIAL HOSPITAL701 GROVE ROAD
GREENVILLE, SC 29605
(864) 455-7000Acute Care Hospitals
PRISMA HEALTH PATEWOOD HOSPITAL175 PATEWOOD DRIVE
GREENVILLE, SC 29615
(864) 797-1000Acute Care Hospitals

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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 1780117416, we treat the final digit (6) 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 54. The final step is to find the difference between that total and the next multiple of ten (60 - 54 = 6).

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
1
Doubled → 2
Pos 2
7
Unchanged
Pos 3
8
Doubled → 16 → 1 + 6
Pos 4
0
Unchanged
Pos 5
1
Doubled → 2
Pos 6
1
Unchanged
Pos 7
7
Doubled → 14 → 1 + 4
Pos 8
4
Unchanged
Pos 9
1
Doubled → 2
Check
6
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 8 → 16 → 7 1 → 2 7 → 14 → 5 1 → 2

Step 2: Add all digits plus the NPI constant

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

2 + 7 + 1 + 6 + 0 + 2 + 1 + 1 + 4 + 4 + 2 + 24 = 54

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

The next multiple of ten after 54 is 60. The difference is the calculated check digit.

60 - 54 = 6
This NPI is valid
The calculated check digit is 6, which matches the last digit of 1780117416.

Other Providers at the Same Location


The following 1 provider is registered at the same or a nearby location.

Clinic/Center (Sleep Disorder Diagnostic)
741 SE MAIN ST
SIMPSONVILLE, SC 29681

Frequently Asked Questions

The NPI number assigned to this healthcare provider is 1780117416, enumerated as an "individual" on April 10, 2017.

The provider is located at 741 SE MAIN ST SIMPSONVILLE, SC 29681 and the phone number is (864) 522-8420.

Internal Medicine with taxonomy code 207RG0100X and a focus in Gastroenterology.

Katherine Macmillan is affiliated with: PRISMA HEALTH BAPTIST EASLEY HOSPITAL, PRISMA HEALTH HILLCREST HOSPITAL, PRISMA HEALTH GREENVILLE MEMORIAL HOSPITAL and PRISMA HEALTH PATEWOOD HOSPITAL.