Dr. Nicholas Cho Ahn , MD
Internal Medicine โข Springfield, IL
751 N Rutledge St, Suite 1100
Springfield, IL 62702
This profile restates public CMS/NPPES data; T-MedInfo gives no medical advice — consult a licensed professional, and call 911 for emergencies.
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Dr. Nicholas Ahn is listed in NPPES under Internal Medicine.
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NPI assigned on July 5, 2013; this date does not establish years in practice.
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Published CMS data list 907 Original Medicare Part B services in 2024.
Source: CMS, Medicare Physician & Other Practitioners โ by Provider and Service, 2024. Published rows only; this is not a quality measure.
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Published Part B service records, 2024:
- 99214 โ Established patient outpatient office visit: 446 service units.
- 99454 โ Remote monitoring of physiologic parameters, initial supply of devices with daily recordings or programmed alerts transmission, each 30 days: 89 service units.
- G0439 โ Annual wellness visit, includes a personalized prevention plan of service (pps), subsequent visit: 85 service units.
Source: CMS, Medicare Physician & Other Practitioners โ by Provider and Service, 2024. Units differ by code; these are not visits or a measure of quality.
CPTยฎ only copyright 2023 American Medical Association. All rights reserved. Service names are shortened from CPT Consumer Friendly Descriptors (CMS data, 2024). CPT notice
See all 10 records in the table ยท Guide: How to read Medicare Part B data
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Published CMS data list 5,519 Medicare Part D prescriptions, including refills, in 2024.
Source: CMS, Medicare Part D Prescribers โ by Provider and Drug, 2024. Published rows only; this is not a quality measure.
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Published Part D records, 2024:
- Atorvastatin Calcium โ 275 prescription fills, including refills.
- Levothyroxine Sodium โ 213 prescription fills, including refills.
- Lisinopril โ 197 prescription fills, including refills.
Source: CMS, Medicare Part D Prescribers โ by Provider and Drug, 2024. Drug names come from pharmacy claims. Listing a drug here is not an endorsement or a recommendation.
See all 131 records in the table ยท Guide: How to read Medicare Part D prescriber data
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More Medicare Part B services than 70% of clinicians listed under Internal Medicine in Springfield, IL (2024, 61 clinicians with data). Median for this group: 537. Middle half: 238 to 934.
More Medicare Part B services than 60% of clinicians listed under Internal Medicine in Illinois (2024, 3,249 clinicians with data). Median for this group: 699. Middle half: 285 to 1,340.
Source: CMS, Medicare Physician & Other Practitioners โ by Provider and Service, 2024. Billing and prescribing volume is not a quality rating.
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Medicare Part B services went from 150 in 2017 to 907 in 2024.
Source: CMS, Medicare Physician & Other Practitioners โ by Provider and Service, 2017โ2024.
Practice Location & Contact Primary Location
751 N Rutledge St
Suite 1100
Springfield, IL 62702
Matched by practice address or phone in NPPES. A shared address or phone does not confirm that this clinician works there.
NPPES lists 1 additional practice-address record in Kalamazoo, MI. See the list
Source: CMS NPPES NPI Registry, practice location records; release date unavailable.
CMS Doctors and Clinicians lists 1 group name: Wayne Memorial Community Health Centers. See the list
Source: CMS Doctors and Clinicians National Downloadable File, release date unavailable.
Listings do not confirm current availability, employment or a shared ownership network.
Medicare Profile & Education
Source: CMS Doctors and Clinicians National Downloadable File
Michigan State University College Of Human Medicine
2013
What Public CMS Data Show
Internal Medicine: NPPES taxonomy is a reported classification, not proof of board certification.
Medicare patients
274 people with Original Medicare in 2024
It gives a sense of how many people with Medicare this clinician treated that year.
Source: CMS, Medicare Physician & Other Practitioners โ by Provider, 2024.
Medicare-allowed amount
About $88,669 in 2024
The total amount Medicare approved for these services in 2024. It includes what Medicare paid and what patients or their other insurance owed, such as the deductible and coinsurance.
It shows the total cost of this clinician's Original Medicare services under Medicare's fee rules.
What this does not show: Medicare-allowed amount
This is not the clinician's income. Part of it can go to a clinic or group practice, staff, equipment or drugs. It is not the price you will pay.
Source: CMS, Medicare Physician & Other Practitioners โ by Provider and Service, 2024.
Paid by Medicare
About $60,981 in 2024
The part of the Medicare-allowed amount that Medicare itself paid in 2024, after patients' deductibles and coinsurance.
The gap between the allowed amount and this number is roughly what patients and their other insurance paid.
What this does not show: Paid by Medicare
This is not the clinician's income and not a measure of quality.
Source: CMS, Medicare Physician & Other Practitioners โ by Provider and Service, 2024.
30-day fills
10,157 standardized 30-day fills in 2024
CMS converts prescriptions to 30-day supplies so they can be compared. A 90-day prescription counts as about three 30-day fills.
What this does not show: 30-day fills
It is not a count of patients and not a measure of quality.
Part D drug cost
$403,959 in 2024
The total cost of these prescriptions in 2024, paid by Medicare drug plans, patients and other payers together.
It shows the total spending on drugs this clinician prescribed, not what any one patient paid.
What this does not show: Part D drug cost
A higher cost often reflects the type of medicines a specialty uses. It is not your out-of-pocket cost and not a measure of quality.
Source: CMS, Medicare Part D Prescribers โ by Provider and Drug, 2024.
Open Payments general payments, program year 2025
All general payments: $215.16 across 10 records.
By nature of payment
- Food and Beverage: $215.16 across 10 records.
Reporting-company totals (3 largest of 8)
- Pfizer Inc.: $41.87 across 2 records.
- Eli Lilly and Company: $38.22 across 2 records.
- ABBVIE INC.: $33.57 across 1 record.
A reported payment does not necessarily mean the financial relationship is improper and is not a measure of care quality. Clinicians can review and dispute these records.
Source: Calculated by T-MedInfo from CMS Open Payments general-payment records for program year 2025 (published June 30, 2026).
Years since graduation
13 years (graduated 2013)
CMS Doctors and Clinicians data list 2013 as the year this clinician finished professional school.
It tells you roughly how long ago the clinician finished school.
What this does not show: Years since graduation
It is not the number of years in practice, and more years does not mean better care.
Source: CMS Doctors and Clinicians National Downloadable File.
NPI first issued
2013
The year this clinician's National Provider Identifier (NPI) was issued. An NPI is a unique 10-digit ID that US health care providers use for billing.
What this does not show: NPI first issued
NPIs have been issued only since 2005, so this year is not necessarily when the clinician started practicing.
Source: CMS NPPES NPI Registry.
Accepts Medicare assignment
CMS data list this clinician as accepting Medicare assignment. This means agreeing to take the Medicare-approved amount as full payment for covered services.
With Original Medicare, you usually pay only your deductible and coinsurance, and the office sends the claim to Medicare for you.
Medicare assignment applies to Original Medicare. It does not tell you whether the clinician is in a Medicare Advantage plan's network, accepts other insurance, or is taking new patients.
Source: CMS Doctors and Clinicians; Medicare.gov, โDoes your provider accept Medicare as full payment?โ
No telehealth indicator
CMS shows this indicator only when recent Medicare claims include telehealth services. The clinician may still offer telehealth; ask the office.
Source: CMS, Telehealth Indicator on Medicare Care Compare (fact sheet, January 2023); CMS Doctors and Clinicians.
Enrolled in Medicare (PECOS)
Dr. Ahn has a Medicare enrollment record in PECOS, the CMS system clinicians use to enroll so they can bill Medicare or order services for people with Medicare.
It does not show whether the clinician accepts assignment, is in your plan's network, or is taking new patients.
Source: CMS Medicare Fee-For-Service Public Provider Enrollment (PECOS); CMS Order and Referring file.
Can order Medicare-covered services
CMS lists Dr. Ahn as eligible to order or refer Medicare Part B clinical laboratory and imaging services, durable medical equipment (DME) and home health services for people with Medicare.
Medicare pays for these items and services only when they are ordered by an eligible clinician.
What this does not show: Can order Medicare-covered services
It does not mean the clinician offers these services directly.
Source: CMS Medicare Fee-For-Service Public Provider Enrollment (PECOS); CMS Order and Referring file.
Compared with the same specialty in Springfield and Illinois
Billing and prescribing volume is not a quality rating.
Medicare Part B services
More Medicare Part B services than 70% of clinicians listed under Internal Medicine in Springfield, IL (2024, 61 clinicians with data). Median for this group: 537. Middle half: 238 to 934.
More Medicare Part B services than 60% of clinicians listed under Internal Medicine in Illinois (2024, 3,249 clinicians with data). Median for this group: 699. Middle half: 285 to 1,340.
Medicare-allowed amount
A higher Medicare-allowed amount than 70% of clinicians listed under Internal Medicine in Springfield, IL (2024, 61 clinicians with data). Median for this group: $58,843. Middle half: $28,433 to $93,905.
A higher Medicare-allowed amount than 60% of clinicians listed under Internal Medicine in Illinois (2024, 3,249 clinicians with data). Median for this group: $67,802. Middle half: $27,619 to $124,679.
Paid by Medicare
A higher Medicare payment amount than 65% of clinicians listed under Internal Medicine in Springfield, IL (2024, 61 clinicians with data). Median for this group: $45,852. Middle half: $21,155 to $71,707.
Close to the middle for clinicians listed under Internal Medicine in Illinois (2024, 3,249 clinicians with data). Median for this group: $52,838. Middle half: $21,117 to $98,214.
Medicare Part D prescriptions
More Part D prescriptions than 80% of clinicians listed under Internal Medicine in Springfield, IL (2024, 85 clinicians with data). Median for this group: 342. Middle half: 80 to 2,561.
More Part D prescriptions than 75% of clinicians listed under Internal Medicine in Illinois (2024, 3,755 clinicians with data). Median for this group: 1,030. Middle half: 99 to 4,658.
Part D drug cost
A higher Part D drug cost than 80% of clinicians listed under Internal Medicine in Springfield, IL (2024, 85 clinicians with data). Median for this group: $10,337. Middle half: $678 to $312,248.
A higher Part D drug cost than 75% of clinicians listed under Internal Medicine in Illinois (2024, 3,755 clinicians with data). Median for this group: $78,716. Middle half: $2,604 to $371,507.
196 active clinicians are listed under Internal Medicine with a practice address in Springfield, IL (7,245 in Illinois).
Addresses are self-reported to NPPES and may be out of date.
Telehealth indicator in Springfield
5.1% of these 196 clinicians have the CMS telehealth indicator.
38.8% of these 196 clinicians are listed by CMS as accepting Medicare assignment.
CMS data by year
Changes may reflect reporting, coverage or privacy limits, not changes in care quality.
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Medicare Part B services
Medicare Part B services increased 505% from 150 in 2017 to 907 in 2024.
- 2017: 150
- 2018: 299
- 2019: 90
- 2023: 397
- 2024: 907
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Medicare-allowed amount
Medicare-allowed amount increased 431% from $16,703 in 2017 to $88,669 in 2024.
- 2017: $16,703
- 2018: $24,430
- 2019: $9,447
- 2023: $45,372
- 2024: $88,669
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Paid by Medicare
Paid by Medicare increased 358% from $13,308 in 2017 to $60,981 in 2024.
- 2017: $13,308
- 2018: $19,374
- 2019: $3,177
- 2023: $38,320
- 2024: $60,981
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Medicare Part D prescriptions
Medicare Part D prescriptions increased 708% from 683 in 2018 to 5,519 in 2024.
- 2018: 683
- 2019: 1,391
- 2020: 99
- 2023: 365
- 2024: 5,519
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30-day fills
30-day fills increased 713% from 1,249 in 2018 to 10,157 in 2024.
- 2018: 1,249
- 2019: 2,980
- 2020: 99
- 2023: 497
- 2024: 10,157
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Part D drug cost
Part D drug cost increased 3859% from $10,203 in 2018 to $403,959 in 2024.
- 2018: $10,203
- 2019: $57,742
- 2020: $2,111
- 2023: $4,356
- 2024: $403,959
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Industry payments (Open Payments)
Industry payments (Open Payments) went from $20.48 in 2019 to $215.16 in 2025.
- 2019: $20.48
- 2023: $1,368.18
- 2024: $2,227.61
- 2025: $215.16
Sources: CMS Medicare Physician & Other Practitioners (2024), CMS Medicare Part D Prescribers (2024), CMS Open Payments (2025), CMS Doctors and Clinicians, CMS NPPES NPI Registry. Specialty names follow the NUCC Health Care Provider Taxonomy.
Text: T-MedInfo ยท Report an error.
Pharma & Medical Device Financial Disclosures
Payments and other transfers of value that drug and medical device companies reported to CMS Open Payments
Program year 2025 (payments made January 1 โ December 31, 2025): fewer than 11 records totaling $215.16.
| Manufacturer | Payment Nature | Product | Type | Amount ($) |
|---|---|---|---|---|
| ABBVIE INC. |
Food and Beverage
In-kind items and services
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UBRELVY | General | $33.57 |
| Pfizer Inc. |
Food and Beverage
In-kind items and services
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NURTEC ODT | General | $26.62 |
| Verona Pharma, Inc. |
Food and Beverage
Cash or cash equivalent
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Ohtuvayre | General | $23.90 |
| Eli Lilly and Company |
Food and Beverage
In-kind items and services
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JARDIANCE | General | $23.23 |
| Dexcom, Inc. |
Food and Beverage
In-kind items and services
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Dexcom G6 Transmitter | General | $22.91 |
| GlaxoSmithKline, LLC. |
Food and Beverage
In-kind items and services
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TRELEGY ELLIPTA | General | $19.72 |
| Otsuka America Pharmaceutical, Inc. |
Food and Beverage
In-kind items and services
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REXULTI | General | $19.44 |
| Boehringer Ingelheim Pharmaceuticals, Inc. |
Food and Beverage
In-kind items and services
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JARDIANCE | General | $15.53 |
| Pfizer Inc. |
Food and Beverage
In-kind items and services
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NURTEC ODT | General | $15.25 |
| Eli Lilly and Company |
Food and Beverage
In-kind items and services
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JARDIANCE | General | $14.99 |
Source: CMS Open Payments, program year 2025, released June 30, 2026.
Performed Procedures & Service Volume
CPTยฎ is a registered trademark of the American Medical Association. CPT codes, descriptions and other data only are copyright 2016โ2023 American Medical Association. All rights reserved. Applicable FARS/HHSARS apply. Descriptions of CPT codes are the AMA's CPT Consumer Friendly Descriptors as published by CMS in the Medicare Physician & Other Practitioners โ by Provider and Service data, 2017โ2024; they are plain-language summaries, not for clinical coding or documentation. HCPCS Level II codes and descriptions are from CMS. Fee schedules, relative value units, conversion factors and/or related components are not assigned by the AMA, are not part of CPT, and the AMA is not recommending their use. The AMA does not directly or indirectly practice medicine or dispense medical services. The AMA assumes no liability for data contained or not contained herein.
| HCPCS Code | Services | Patients | Submitted Charge | Medicare Allowed |
|---|---|---|---|---|
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99214
Established patient office or other outpatient visit with moderate level of decision making, if using time, 30 minutes or more
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446 | 221 | $200.00 | $120.72 |
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99454
Remote monitoring of physiologic parameters, initial supply of devices with daily recordings or programmed alerts transmission, each 30 days
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89 | 24 | $129.00 | $43.07 |
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G0439
Annual wellness visit, includes a personalized prevention plan of service (pps), subsequent visit
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85 | 85 | $285.00 | $122.35 |
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99215
Established patient office or other outpatient visit with high level of medical decision making, if using time, 40 minutes or more
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68 | 61 | $250.00 | $170.84 |
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99457
Management using the results of remote vital sign monitoring per calendar month, first 20 minutes
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58 | 26 | $129.00 | $46.01 |
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96372
Injection of drug or substance under skin or into muscle
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41 | 16 | $40.00 | $13.43 |
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J3420
Injection, vitamin b-12 cyanocobalamin, up to 1000 mcg
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34 | 14 | $10.00 | $1.21 |
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99213
Established patient office or other outpatient visit with low level od decision making, if using time, 20 minutes or more
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31 | 29 | $125.00 | $86.02 |
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G0008
Administration of influenza virus vaccine
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28 | 28 | $40.00 | $30.77 |
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90662
Influenza vaccine split virus, preservative free
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27 | 27 | $140.00 | $81.09 |
Source: CMS Part B by Provider and Service, 2024; services under 11 beneficiaries omitted by CMS. Privacy limits
Submitted charges are billed amounts, not a price quote for your visit.
Medicare Part D Prescribing Profile & Medications
Medicare Part D prescriptions filled, including refills, in 2024.
| Brand Name | Generic Name | Prescriptions | Day Supply | Total Cost | Patients |
|---|---|---|---|---|---|
| Atorvastatin Calcium | Atorvastatin Calcium | 275 | 21,488 | $2,995.59 | 109 |
| Levothyroxine Sodium | Levothyroxine Sodium | 213 | 13,008 | $2,027.60 | 62 |
| Lisinopril | Lisinopril | 197 | 13,839 | $1,349.61 | 64 |
| Alprazolam | Alprazolam | 185 | 5,139 | $1,217.47 | 56 |
| Losartan Potassium | Losartan Potassium | 153 | 9,269 | $1,711.07 | 44 |
| Metoprolol Succinate | Metoprolol Succinate | 145 | 9,767 | $2,172.78 | 51 |
| Amlodipine Besylate | Amlodipine Besylate | 143 | 10,372 | $1,293.37 | 56 |
| Omeprazole | Omeprazole | 143 | 10,264 | $2,169.96 | 58 |
| Rosuvastatin Calcium | Rosuvastatin Calcium | 141 | 9,232 | $1,962.41 | 48 |
| Pantoprazole Sodium | Pantoprazole Sodium | 135 | 8,360 | $1,600.92 | 48 |
| Metformin Hcl | Metformin Hcl | 131 | 9,535 | $681.15 | 46 |
| Simvastatin | Simvastatin | 123 | 8,236 | $1,199.84 | 40 |
| Gabapentin | Gabapentin | 116 | 4,710 | $1,656.00 | 31 |
| Albuterol Sulfate Hfa | Albuterol Sulfate | 101 | 2,371 | $2,676.75 | 37 |
| Hydrocodone-Acetaminophen | Hydrocodone/Acetaminophen | 97 | 2,465 | $2,387.48 | 22 |
| Furosemide | Furosemide | 92 | 5,054 | $469.11 | 38 |
| Hydrochlorothiazide | Hydrochlorothiazide | 80 | 5,686 | $382.68 | 29 |
| Lorazepam | Lorazepam | 79 | 2,129 | $378.70 | 18 |
| Tamsulosin Hcl | Tamsulosin Hcl | 77 | 4,769 | $1,245.51 | 22 |
| Sertraline Hcl | Sertraline Hcl | 75 | 4,418 | $531.94 | 22 |
| Potassium Chloride | Potassium Chloride | 72 | 3,566 | $1,358.03 | 24 |
| Metoprolol Tartrate | Metoprolol Tartrate | 68 | 4,575 | $568.49 | 25 |
| Fluticasone Propionate | Fluticasone Propionate | 67 | 2,970 | $832.19 | 38 |
| Escitalopram Oxalate | Escitalopram Oxalate | 66 | 3,493 | $506.25 | 21 |
| Eliquis | Apixaban | 62 | 2,640 | $51,272.81 | 17 |
(top 25 shown)
Source: CMS Part D by Provider and Drug, 2024; rows below 11 claims omitted by CMS; volume isn’t quality. Privacy limits
Specialties & License Numbers Reported to NPPES
NUCC Taxonomy Code: 207R00000X
A physician who provides long-term, comprehensive care in the office and the hospital, managing both common and complex illness of adolescents, adults and the elderly. Internists are trained in the diagnosis and treatment of cancer, infections and diseases affecting the heart, blood, kidneys, joints and digestive, respiratory and vascular systems. They are also trained in the essentials of primary care internal medicine, which incorporates an understanding of disease prevention, wellness, substance abuse, mental health and effective treatment of common problems of the eyes, ears, skin, nervous system and reproductive organs.
NUCC Taxonomy Code: 207R00000X
A physician who provides long-term, comprehensive care in the office and the hospital, managing both common and complex illness of adolescents, adults and the elderly. Internists are trained in the diagnosis and treatment of cancer, infections and diseases affecting the heart, blood, kidneys, joints and digestive, respiratory and vascular systems. They are also trained in the essentials of primary care internal medicine, which incorporates an understanding of disease prevention, wellness, substance abuse, mental health and effective treatment of common problems of the eyes, ears, skin, nervous system and reproductive organs.
NUCC Taxonomy Code: 2084P0800X
A Psychiatrist specializes in the prevention, diagnosis, and treatment of mental disorders, emotional disorders, psychotic disorders, mood disorders, anxiety disorders, substance-related disorders, sexual and gender identity disorders and adjustment disorders. Biologic, psychological, and social components of illnesses are explored and understood in treatment of the whole person. Tools used may include diagnostic laboratory tests, prescribed medications, evaluation and treatment of psychological and interpersonal problems with individuals and families, and intervention for coping with stress, crises, and other problems.
Additional State Medicaid & Healthcare Payer Identifiers
Medicare (PECOS) Enrollment & Ordering Eligibility
Source: CMS PECOSPRACTITIONER - INTERNAL MEDICINE
I20230227003063
PA
7719272400
Sources: CMS Provider Enrollment and Order and Referring. Medicare enrollment is a billing status, not an accreditation or quality rating.
Medicare Group Practice Enrollments
Source: CMS Doctors and Clinicians National Downloadable File
Wayne Memorial Community Health Centers
358 Hamlin Hwy, Lake Ariel, PA 184369382
Phone: 5706892242
Wayne Memorial Community Health Centers
543 Easton Tpke, Lake Ariel, PA 184364718
Phone: 5706899965
Secondary Practice Locations
5629 Stadium Dr Ste B
Kalamazoo, MI 490091952
Phone: 2695443270
Clinicians Sharing This Practice Address or Phone
Clinicians sharing this NPPES address, phone or fax; a shared contact does not mean they work together.
Internal Medicine
Doctor of Medicine (M.D.)
Family Medicine
Doctor of Medicine (M.D.)
Nurse Practitioner - Family
Internal Medicine - Cardiovascular Disease
Doctor of Medicine (M.D.)
Internal Medicine - Cardiovascular Disease
Doctor of Medicine (M.D.), Master of Public Health
Internal Medicine
Doctor of Medicine (M.D.)
Career & Practice History Timeline
Changes recorded in monthly NPPES data files: addresses, names, credentials, specialties and NPI status
Registered at 751 N RUTLEDGE ST, SUITE 1100, SPRINGFIELD, IL 62702 (Tel: 2175458000)
Internal Medicine (license number reported to NPPES: MI 4301114315)
NPI status registered as active in NPPES database
Registered at 751 N RUTLEDGE ST, SUITE 1100, SPRINGFIELD, IL 627024968 (Tel: 2175458000)
Registered at PO BOX 19648, SPRINGFIELD, IL 627949648 (Tel: 2175458000)
Recorded as NICHOLAS AHN, M.D.
Internal Medicine (license number reported to NPPES: IL 036-141124)
First registered as active Individual Practitioner in NPPES Database.
NPI Administrative Meta
Other Internal Medicine Providers in Springfield
- Dr. Gary Rull, MD
- Dr. Bilal Chaudhry, MD
- Dr. James Lafata, MD
- Dr. Shashi Dhar Rajuri, MD
- Dr. Martha Hlafka, MD
- Dr. Mulham Alom, MD
Mailing Address
Po Box 19648
Springfield, IL 627949648
Phone: 2175458000