DR. LARRY JOHNSTON D.O.
NPI 1386036333
Internal Medicine - Gastroenterology in Ames, IA

Q: What is Larry Johnston's NPI number?

The NPI number for Larry Johnston is 1386036333. It was assigned to this individual provider in the NPPES registry on February 28, 2015.

Q: What is Larry Johnston's specialty?

The primary specialty registered for this NPI is Internal Medicine, specializing in Gastroenterology, with taxonomy code 207RG0100X.

Q: When was this NPI record last updated?

The NPPES record for Larry Johnston was last updated on August 2, 2022. NPI Profile syncs weekly with the NPPES registry data releases published by CMS. This NPI record was last updated 4 years ago. If this record has changed at CMS more recently, you can request an on-demand re-check against the live CMS registry, directly from this page.

Active since February 28, 2015PECOS EnrolledAccepts Medicare Assignment

1215 DUFF AVE, AMES, IA 50010(515) 239-4450 Get Directions Write a Review

NPPES record last updated: August 2, 2022. Verified against the NPPES registry weekly; last sync: October 25, 2026.

Record update history: Aug 2, 2022, Nov 24, 2018, May 23, 2018 (3 updates tracked since 2018).

On this page

About Dr. Larry Johnston D.o. NPPES

Official registry information on file with the National Plan and Provider Enumeration System.

DR. LARRY JOHNSTON D.O. (NPI 1386036333) is an individual gastroenterology provider in Ames, Iowa, licensed in Iowa (05983) and active in the NPI registry since February 2015. He is enrolled in Medicare PECOS, is affiliated with Mary Greeley Medical Center, and is a graduate of Oklahoma State University College Of Osteopathic Medicine (2015).

NPPES Registry Identity

NPI1386036333

Entity TypeIndividualMale

Primary Taxonomy207RG0100X

Provider Legal NameDR. LARRY JOHNSTONCredential: D.O.

Location Address1215 DUFF AVEAmes, IA 50010-5469

Mailing Address1215 Duff AveAmes, IA 50010-5469 · (515) 239-4400

Phone(515) 239-4450

Sole ProprietorYes

Medical School CMSOklahoma State University College Of Osteopathic MedicineGraduated 2015

Enumeration DateFebruary 28, 2015

Last NPPES UpdateAugust 2, 20223 updates tracked since enumeration

NPPES CertifiedAugust 2, 2022

✔ NPI 1386036333 is a valid, active identifier and passes the ISO check-digit test.

Specialties & Licenses 2

★ Primary SpecialtyInternal Medicine · GastroenterologyAllopathic & Osteopathic Physicians

Taxonomy Code207RG0100X

License✔ Licensed in IA · 05983

Definition

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.

Also ListedInternal MedicineTaxonomy 207R00000X · License 6004 (OK)

1215 DUFF AVE, Ames, IA 50010

Open in Google Maps ↗

Accepted Insurance

The full list of accepted plans is on the Insurance tab. Issuers include Wellmark Health Plan of Iowa, Inc..Insurance ›

Medicare Participation & PECOS CMS

Medicare enrollment, assignment, billing reassignment, and ordering and referring status from CMS.

Medicare Enrollment Status

✔

Enrolled in Medicare and accepts Medicare assignment

Dr. Larry Johnston D.o. is registered in PECOS and agrees to accept the Medicare-approved amount as full payment. Medicare patients are not billed beyond the standard deductible and coinsurance.

PECOS PAC ID1355729906

PECOS Enrollment IDI20220609002409

Eligible to Order & Refer✔ Part B Labs & Imaging✔ Durable Medical Equipment✔ Home Health Agency✔ Power Mobility DevicesPer the CMS Ordering and Referring file. Eligibility means Medicare pays claims that this provider orders or refers for these categories.

Medicare Billing Reassignment

Medicare enrollment records show Larry Johnston reassigns Medicare billing to 1 organization. The organization bills Medicare for the services this provider delivers there.

Mcfarland Clinic PC

Same address

Multi-Specialty

1215 DUFF AVENUE
Ames, IA 50010

Reassigned Medicare billing, Iowa enrollment
331 clinicians in this Medicare group

NPI 1639135643 (515) 239-4400

Source: CMS Revalidation Reassignment List, October 2026 release. Reassignment records can lag staffing changes; confirm a current affiliation with the organization.

Areas of Expertise CMS Part B claims 22

Services this provider delivered to Medicare fee-for-service patients, from the CMS Medicare utilization data. Higher counts generally reflect more experience with a service; care delivered outside Medicare is not included.

Moderate sedation services provided by the same physician or other qualified health care professional performing a gastrointestinal endoscopic service that sedation supports, requiring the presence of an independent trained observer to assist in the monito G0500

Moderate sedation is a method where a physician uses medication to help you relax during a gastrointestinal endoscopy. An independent trained observer will be present to monitor your vital signs and ensure your safety throughout the procedure. It's a common and safe practice.

340 services314 patients

Removal of polyps or growths of large bowel using an endoscope with mechanical snare 45385

This procedure involves using a thin, flexible tube called an endoscope to examine the large bowel. If any abnormal growths or polyps are found, a tool called a mechanical snare is used to remove them. This is a common method to prevent potential health issues.

125 services125 patients

Biopsy of esophagus, stomach, and/or upper small bowel using a flexible endoscope 43239

This procedure involves using a thin, flexible tube with a light and camera, known as an endoscope, to examine the esophagus, stomach, and upper part of the small intestine. Small tissue samples are taken for further examination to help diagnose various conditions.

57 services55 patients

Established patient office or other outpatient visit with moderate level of decision making, if using time, 30 minutes or more 99214

This is a routine check-up for patients who have previously visited our clinic. It involves a comprehensive review of your health and any ongoing treatments. The consultation lasts between 30-39 minutes, allowing enough time to discuss any concerns.

53 services38 patients

Initial hospital care with moderate level of medical decision making, if using time, at least 75 minutes 99223

Initial hospital inpatient care per day, typically 70 minutes, refers to the daily medical service provided to patients admitted to the hospital. This includes a comprehensive evaluation, diagnosis, treatment plan, and monitoring of your health condition. It ensures your well-being during your hospital stay.

46 services45 patients

Colorectal cancer screening; colonoscopy on individual not meeting criteria for high risk G0121

Colorectal cancer screening, such as a colonoscopy, is a preventive measure to detect early signs of cancer in the large intestine. For individuals not at high risk, it's typically recommended at age 50. A small, flexible tube with a camera is used to examine your colon. It's a safe, effective way to catch issues early.

40 services40 patients

Subsequent hospital care with moderate levelof medical decision making, if using time, at least 35 minutes 99232

Follow-up hospital inpatient care involves daily check-ups while you're admitted in the hospital. Typically, a healthcare provider spends about 25 minutes each day reviewing your condition, adjusting treatment if needed, and answering any questions you might have.

39 services30 patients

Diagnostic exam of esophagus, stomach, and/or upper small bowel using a flexible endoscope 43235

This procedure, known as an upper endoscopy, involves inserting a thin, flexible tube with a camera down the throat to examine the esophagus, stomach, and upper small bowel. It helps diagnose conditions like ulcers or inflammation.

38 services35 patients

Insertion of needle into vein for collection of blood sample 36415

This procedure involves inserting a small needle into a vein, typically in your arm, to collect a blood sample. It's a quick and simple process to help diagnose or monitor health conditions. You may feel a small prick, but discomfort is minimal.

34 services25 patients

Established patient office or other outpatient visit with low level od decision making, if using time, 20 minutes or more 99213

This is a routine visit for patients who have already been seen by the healthcare provider. During this approximately 20-29 minute appointment, your health status will be evaluated and any necessary treatments or tests will be discussed. It's a chance to address any health concerns you may have.

33 services25 patients

Subsequent hospital care with moderate levelof medical decision making, if using time, at least 50 minutes 99233

Follow-up hospital inpatient care per day typically involves a 35-minute check-up by your healthcare provider. This service includes monitoring your health progress, adjusting your treatment plan if needed, and answering any questions you may have about your condition or care.

29 services23 patients

Diagnostic exam of large bowel using a flexible endoscope 45378

This procedure, known as a colonoscopy, involves using a flexible tube with a light and camera to examine the large intestine. It helps detect any abnormalities such as polyps or inflammation. It's a standard procedure to ensure gut health.

26 services26 patients

Balloon dilation of esophagus, stomach, and/or upper small bowel using a flexible endoscope, less than 3.0 cm 43249

This procedure involves using a flexible tube with a camera, called an endoscope, to gently expand narrowed areas in your esophagus, stomach, or upper small bowel. A small balloon is inflated, making it easier for food and liquid to pass through. It's safe and effective.

22 services17 patients

Blood test, comprehensive group of blood chemicals 80053

A comprehensive group of blood chemicals test, also known as a comprehensive metabolic panel, is a blood test that measures your sugar level, electrolyte and fluid balance, kidney function, and liver function. This helps to check your body's overall health.

21 services15 patients

Colorectal cancer screening; colonoscopy on individual at high risk G0105

Colorectal cancer screening, specifically a colonoscopy, is a preventive measure for those at high risk. A thin, flexible tube with a camera inspects the colon to spot any abnormal growths. This test helps detect potential issues early, enhancing the effectiveness of treatment.

21 services21 patients

New patient office or other outpatient visit with moderate level of medical decision making, if using time, 45 minutes or more 99204

This is a first-time office or outpatient visit lasting between 45-59 minutes. The healthcare provider evaluates your health, discusses your medical history, and may suggest further tests or treatments. It's an opportunity to ask questions and understand your health better.

19 services19 patients

Complete blood cell count (red cells, white blood cell, platelets), automated test and automated differential white blood cell count 85025

A Complete Blood Cell Count is a common test that measures various components of the blood, including red cells (carry oxygen), white cells (fight infection), and platelets (help blood clot). An automated test ensures accuracy. The differential count provides detailed information about white cell types.

18 services16 patients

Biopsy of large bowel using a flexible endoscope 45380

A biopsy of the large bowel using a flexible endoscope is a procedure where a thin, flexible tube with a camera is inserted through the rectum to examine the bowel. If abnormal tissue is found, a small sample is taken for further examination. This helps in diagnosing conditions like inflammation, polyps, or cancer.

16 services16 patients

Blood test, clotting time 85610

A clotting time blood test helps determine how quickly your blood forms clots, a process crucial to stop bleeding. During the test, a small blood sample is taken from your arm. The sample is then analyzed in a lab to see how long it takes for a clot to form.

16 services14 patients

Review by radiologist of image from tube placement into bile duct using an endoscope 74328

This procedure involves a specialist, called a radiologist, examining an image taken during a tube placement into your bile duct. The tube is inserted with the help of a tool called an endoscope. This allows the doctor to check for any issues or abnormalities in your bile duct.

15 services14 patients

Control of bleeding of esophagus, stomach, and/or upper small bowel using a flexible endoscope 43255

This procedure involves using a flexible tube with a light, called an endoscope, to examine and treat bleeding in the esophagus, stomach, or upper small bowel. It's a safe, effective way to control bleeding and ensure your digestive health.

12 services12 patients

Incision of pancreatic outlet using a flexible endoscope 43262

This procedure involves a small cut in the outlet of the pancreas using a flexible tube with a camera, called an endoscope. It helps doctors diagnose and treat conditions affecting the pancreas, enhancing patient comfort and recovery.

11 services11 patients

Hospital Affiliations CMS Care Compare 2

Hospitals where this provider delivers care, identified from recent Medicare claims and place-of-service records.

Mary Greeley Medical Center

Acute Care Hospitals · Ames, IA

4/5 CMS rating

OwnershipGovernment - Local

CMS Certification Number160030

Location1111 Duff AvenueAmes, IA 50010 · Story County

Emergency services Birthing friendly

Van Diest Medical Center

Critical Access Hospitals · Webster City, IA

5/5 CMS rating

OwnershipVoluntary non-profit - Other

CMS Certification Number161361

Location2350 Hospital DriveWebster City, IA 50595 · Hamilton County

Emergency services

Physician Visit Costs CMS claims · ZIP area

Typical Medicare office-visit costs in the 50010 ZIP code area, from fee-for-service claims. These are area statistics, not this provider’s prices; actual charges vary by service and coverage.

New Patient

$122.23 typical visit price

range $52.96 – $161.40

Typical copayment $30.55 (range $13.24 – $40.35)

Most-billed visit code 99204

Established Patient

$94.05 typical visit price

range $16.91 – $131.98

Typical copayment $23.51 (range $4.22 – $32.99)

Most-billed visit code 99214

Amounts reflect what Medicare beneficiaries in this ZIP area are typically charged for office visits. Patients with other coverage should check their individual plans.

Other Providers at the Same Location NPPES 20

Providers registered at the same practice address, or within the immediate area, according to the NPPES registry.

KARL HAMOUCHE

Radiology (Diagnostic Radiology)

1215 DUFF AVE
AMES, IA 50010

Story County (515) 239-4456

MARK R. MORRIS PA-C

Physician Assistant (Medical)

1215 DUFF AVE, MCFARLAND CLINIC, PC
AMES, IA 50010

Story County (515) 239-4496

NICHOLAS LELAND SKIBBA PHARMD

Pharmacist (Ambulatory Care)

1215 DUFF AVE
AMES, IA 50010

Story County (515) 239-4400

TROY MICHAEL MCDONOUGH M.S.P.T.

Physical Therapist

1215 DUFF AVE
AMES, IA 50010

Story County (515) 956-4095

BRIAN O'TOOL

Physical Therapist

1215 DUFF AVE
AMES, IA 50010

Story County (515) 956-4095

MATIAS ALBERTO GERSTNER MD

Internal Medicine

1215 DUFF AVE
AMES, IA 50010

Story County (515) 239-4431

DR. JUSTIN WADE RASH PHARMD

Pharmacist

1215 DUFF AVE
AMES, IA 50010

Story County (515) 232-7315

NATALIE NELSON

Physician Assistant

1215 DUFF AVE
AMES, IA 50010

Story County (515) 239-4475

Frequently Asked Questions NPPES & CMS

Common questions about this NPI record, answered from the official NPPES registry and CMS datasets shown on this page.

What is Larry Johnston's NPI number?

The NPI number for Larry Johnston is 1386036333. It was assigned to this individual provider in the NPPES registry on February 28, 2015.

Where is Larry Johnston located?

Larry Johnston practices at 1215 Duff Ave, Ames, IA 50010. The listed phone number is (515) 239-4450.

What is Larry Johnston's specialty?

The primary specialty registered for this NPI is Internal Medicine, specializing in Gastroenterology, with taxonomy code 207RG0100X.

Is Larry Johnston enrolled in Medicare?

Yes. Larry Johnston is registered in the Medicare PECOS system and accepts Medicare assignment, which means accepting the Medicare-approved amount as payment in full for covered services.

Which organization bills Medicare for Larry Johnston's services?

According to the CMS Revalidation Reassignment List (October 2026 release), Larry Johnston reassigns Medicare benefits to Mcfarland Clinic PC (Ames, IA). The reassignment is filed with Medicare on form CMS-855R, signed by both the clinician and the organization, and lets the organization bill Medicare and receive payment for Larry Johnston's services. Reassignment records can lag staffing changes; confirm current arrangements with the organization.

What insurance does Larry Johnston accept?

Health plans from Wellmark Health Plan of Iowa, Inc. list Larry Johnston as in-network in at least one marketplace plan. Coverage varies by plan and year; verify with the insurer or the provider before a visit.

Is Larry Johnston affiliated with any hospitals?

According to CMS data, Larry Johnston is affiliated with Mary Greeley Medical Center and Van Diest Medical Center.

When was this NPI record last updated?

The NPPES record for Larry Johnston was last updated on August 2, 2022. NPI Profile syncs weekly with the NPPES registry data releases published by CMS. This NPI record was last updated 4 years ago. If this record has changed at CMS more recently, you can request an on-demand re-check against the live CMS registry, directly from this page.