DR. THOMAS G AHN MD
NPI 1669556866
Internal Medicine in Los Angeles, CA

Q: What is Thomas Ahn's NPI number?

The NPI number for Thomas Ahn is 1669556866. It was assigned to this individual provider in the NPPES registry on October 24, 2006.

Q: What is Thomas Ahn's specialty?

The primary specialty registered for this NPI is Internal Medicine with taxonomy code 207R00000X.

Q: When was this NPI record last updated?

The NPPES record for Thomas Ahn was last updated on December 14, 2025. NPI Profile syncs weekly with the NPPES registry data releases published by CMS. This NPI record was last updated 7 months 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 October 24, 2006PECOS EnrolledAccepts Medicare Assignment

31.47/100

CMS Quality Rating

2080 CENTURY PARK E STE 1410, LOS ANGELES, CA 90067(310) 277-7600(310) 221-8839 Get Directions Write a Review

NPPES record last updated: December 14, 2025. Verified against the NPPES registry weekly; last sync: August 02, 2026.

Record update history: Dec 14, 2025, Mar 17, 2025 (2 updates tracked since 2025).

On this page

About Dr. Thomas G Ahn Md NPPES

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

DR. THOMAS G AHN MD (NPI 1669556866) is an individual internal medicine provider in Los Angeles, California, licensed in California (G61939) and active in the NPI registry since October 2006. He is enrolled in Medicare PECOS and is a graduate of Virginia Commonwealth University, School Of Medicine (1979).

NPPES Registry Identity

NPI1669556866

Entity TypeIndividualMale

Primary Taxonomy207R00000X

Provider Legal NameDR. THOMAS G AHNCredential: MD

Location Address2080 CENTURY PARK E STE 1410Los Angeles, CA 90067-2017

Mailing Address2080 Century Park E Ste 1410Los Angeles, CA 90067-2017 · (310) 277-7600 · Fax (310) 553-9103

Phone(310) 277-7600

Fax(310) 221-8839

Sole ProprietorYes

Medical School CMSVirginia Commonwealth University, School Of MedicineGraduated 1979

Enumeration DateOctober 24, 2006

Last NPPES UpdateDecember 14, 20252 updates tracked since enumeration

NPPES CertifiedDecember 14, 2025

✔ NPI 1669556866 is a valid, active identifier and passes the ISO check-digit test.

Specialties & Licenses 2

★ Primary SpecialtyInternal MedicineAllopathic & Osteopathic Physicians

Taxonomy Code207R00000X

License✔ Licensed in CA · G61939

Definition

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.

Also ListedInternal Medicine · Endocrinology, Diabetes & MetabolismTaxonomy 207RE0101X · License G61939 (CA)

2080 CENTURY PARK E STE 1410, Los Angeles, CA 90067

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Medicare Participation & PECOS CMS

Medicare enrollment, assignment, and ordering and referring status from the CMS PECOS system.

Medicare Enrollment Status

✔

Enrolled in Medicare and accepts Medicare assignment

Dr. Thomas G Ahn Md 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 ID1759560766

PECOS Enrollment IDI20110124000421

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.

Areas of Expertise CMS Part B claims 30

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.

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.

673 services393 patients

Blood test, thyroid stimulating hormone (tsh) 84443

A TSH blood test measures the level of thyroid stimulating hormone in your body. This hormone is produced by the pituitary gland and regulates how your thyroid works. It's a simple procedure where a small amount of blood is drawn from your arm for analysis.

575 services372 patients

Blood test, lipids (cholesterol and triglycerides) 80061

A lipid panel is a blood test that measures fats and fatty substances, such as cholesterol and triglycerides. These substances are used by your body as a source of energy. High levels can lead to health issues, including heart disease.

556 services365 patients

Uric acid level, blood 84550

A blood uric acid level test measures the amount of uric acid in your blood. Uric acid is a waste product that your body produces when it breaks down purines, substances found in your body and in certain foods. High levels may lead to gout or kidney stones.

547 services349 patients

Thyroxine (thyroid chemical), free 84439

The Thyroxine (thyroid chemical), free test is a blood test that measures the level of free T4 in your body. T4 is a hormone produced by your thyroid gland and is essential for growth and metabolism. If your T4 levels are too high or too low, it could indicate a thyroid disorder.

546 services365 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.

544 services347 patients

Lactate dehydrogenase (enzyme) level 83615

A Lactate Dehydrogenase level test measures the amount of this enzyme in your body. It's often done when tissue damage is suspected, as high levels can indicate issues like heart disease, lung disease, liver disease, or blood disorders. This test helps in diagnosing and monitoring these conditions.

544 services348 patients

Glutamyltransferase (liver enzyme) level 82977

Glutamyltransferase (GGT) level is a blood test that helps check your liver's health. High GGT levels may indicate liver disease or damage. The test involves a simple blood draw and results help your doctor understand your liver's condition better.

532 services347 patients

Vitamin d-3 level 82306

A Vitamin D-3 level test measures the amount of Vitamin D-3, a crucial nutrient, in your body. This test helps identify if your levels are too low or too high. Low levels may lead to bone weakness, while high levels could harm your kidneys. It's a simple blood test.

525 services364 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.

510 services335 patients

Phosphate level 84100

A phosphate level test measures the amount of phosphate in your blood. Phosphate is a chemical that contains the mineral phosphorus, crucial for energy production, muscle and nerve function, and bone growth. Imbalances may indicate kidney disease or other health issues.

493 services332 patients

Red blood cell sedimentation rate, to detect inflammation, non-automated 85651

The Red Blood Cell Sedimentation Rate test measures how quickly red blood cells settle at the bottom of a test tube. If they settle faster than normal, it may indicate inflammation in the body. This test is non-automated, meaning it's manually performed by a lab technician.

474 services331 patients

Cyanocobalamin (vitamin b-12) level, unsaturated binding capacity 82608

This test measures the level of Vitamin B-12 and its binding capacity in your body. Vitamin B-12 is essential for nerve function and the creation of red blood cells. If levels are too low or high, it may indicate a health issue.

472 services342 patients

Hemoglobin a1c level 83036

Hemoglobin A1c (HbA1c) is a test that measures your average blood sugar level over the past 2-3 months. It's used to monitor how well diabetes is being controlled. High levels may indicate that your diabetes treatment plan needs adjustment.

417 services283 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.

351 services189 patients

Established patient office or other outpatient visit with high level of medical decision making, if using time, 40 minutes or more 99215

This service involves a follow-up appointment for existing patients, lasting between 40 to 54 minutes. During this time, your healthcare provider will assess your current health status, discuss any changes or concerns, review your treatment plan, and answer any questions you may have.

288 services255 patients

Psa (prostate specific antigen) measurement, total 84153

PSA measurement is a simple blood test that checks for a specific protein produced by your body. High levels could indicate a health issue that needs further investigation. It's often used to monitor general wellness and is part of routine health screening.

237 services156 patients

Routine electrocardiogram (ecg) using at least 12 leads with interpretation and report 93000

An electrocardiogram (ECG) is a non-invasive test that records your heart's electrical activity. Using 12 leads attached to your body, it captures data to help identify heart conditions. A doctor interprets the results and provides a report.

212 services185 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.

174 services132 patients

Stool analysis for blood to screen for colon tumors 82270

A stool analysis for blood is a non-invasive procedure used to check for the presence of hidden blood in your stool. This can be an early sign of colon tumors. The test involves collecting a small sample of stool at home and sending it to a lab for analysis.

165 services165 patients

Injection of drug or substance under skin or into muscle 96372

This procedure involves administering medication directly under the skin or into a muscle. A small needle is used to inject the drug, allowing it to be absorbed quickly into the bloodstream. It's a common method for delivering a variety of medications.

116 services17 patients

Established patient office or other outpatient visit with straightforward medical decision making, if using time, 10 minutes or more 99212

This is a routine check-up for patients who have previously seen the doctor. During this 10-19 minute visit, the doctor will review your health status, discuss any concerns, and manage ongoing treatments or medications. It's a chance to ensure your health is on track.

86 services43 patients

Injection, vitamin b-12 cyanocobalamin, up to 1000 mcg J3420

This is a procedure where a small dose of Vitamin B-12, also known as Cyanocobalamin, is injected into your body. This vitamin is essential for nerve function and the production of red blood cells. It's often used to treat vitamin B-12 deficiency.

64 services16 patients

Urinalysis using microscope 81015

Urinalysis with a microscope is a test that helps detect issues in your body. A small sample of your urine is examined under a microscope. This allows the detection of substances not visible to the naked eye, aiding in diagnosing various health conditions.

54 services54 patients

Continuous monitoring of blood sugar level in tissue fluid using sensor under skin with interpretation and report 95251

This procedure involves placing a small sensor under your skin to continuously monitor your blood sugar levels in tissue fluid. The data is interpreted and a report is generated to help manage your diabetes more effectively.

46 services26 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.

39 services39 patients

Testosterone (hormone) level, total 84403

A total testosterone level test measures the amount of a key hormone in your body. This hormone influences various body functions such as muscle mass, energy levels, and mood. The test involves a simple blood draw, and results help monitor health conditions.

27 services23 patients

Iron level 83540

An iron level test measures the amount of iron in your blood. Iron is crucial for producing hemoglobin, a protein in red blood cells that carries oxygen throughout your body. This test helps identify iron deficiencies or excesses, which can lead to conditions like anemia or hemochromatosis.

21 services20 patients

Iron binding capacity 83550

Iron binding capacity is a blood test that measures how well your body can bind and transport iron. This helps your healthcare provider assess if your body has too little or too much iron, which can indicate certain health conditions.

21 services20 patients

Thyroid hormone, t3 measurement, free 84481

The T3 measurement, free, is a blood test that checks the level of a hormone called triiodothyronine. This hormone is produced by your thyroid, a small gland in your neck. It plays a key role in regulating your body's metabolism and energy use.

19 services18 patients

Physician Visit Costs CMS claims · ZIP area

Typical Medicare office-visit costs in the 90067 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

$142.39 typical visit price

range $62.96 – $187.60

Typical copayment $35.59 (range $15.74 – $46.90)

Most-billed visit code 99204

Established Patient

$109.96 typical visit price

range $20.84 – $153.61

Typical copayment $27.49 (range $5.21 – $38.40)

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.

Medicare Quality Performance CMS QPP · MIPS

Performance in the CMS Quality Payment Program: the MIPS final score across four weighted categories, and the individual quality measures reported to Medicare.

31.47/100

MIPS Final ScoreMerit-based Incentive Payment System · CMS Quality Payment Program

Individually scored

Quality

60.34

Improvement Activities

Cost

24.46

Reported Quality Measures

Preventive Care and Screening: Body Mass Index (BMI) Screening and Follow-Up Plan

Percentage of patients aged 18 years and older with a BMI documented during the current encounter or during the previous twelve months AND with a BMI outside of normal parameters, a follow-up plan is documented during the encounter or during the previous…

100%304 patients5/55-star benchmark: 100%

Providers report different measures because they deliver different services; reporting more or less information is not a reflection of quality. Star ratings appear only where CMS assigned them.

Referred Medical Equipment & Supplies CMS DME claims 4

Durable medical equipment, devices and supplies this provider ordered from DME suppliers for patients, from Medicare fee-for-service claims.

Blood glucose test or reagent strips for home blood glucose monitor, per 50 strips A4253

DME-Other DME · category DE017N

19 suppliers57 claims173 services$6.49 avg. paid by Medicare

Lancets, per box of 100 A4259

DME-Medical/Surgical Supplies · category DA000N

6 suppliers12 claims15 services$1.17 avg. paid by Medicare

Nasal interface (mask or cannula type) used with positive airway pressure device, with or without head strap A7034

DME-Other DME · category DE001N

3 suppliers11 claims11 services$43.60 avg. paid by Medicare

Supply allowance for therapeutic continuous glucose monitor (cgm), includes all supplies and accessories, 1 month supply = 1 unit of service K0553

DME-Other DME · category DE017N

9 suppliers198 claims198 services$187.95 avg. paid by Medicare

Dollar amounts are the average Medicare paid the supplier per service. They are not the cost to the patient.

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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 Thomas Ahn's NPI number?

The NPI number for Thomas Ahn is 1669556866. It was assigned to this individual provider in the NPPES registry on October 24, 2006.

Where is Thomas Ahn located?

Thomas Ahn practices at 2080 Century Park E Ste 1410, Los Angeles, CA 90067. The listed phone number is (310) 277-7600.

What is Thomas Ahn's specialty?

The primary specialty registered for this NPI is Internal Medicine with taxonomy code 207R00000X.

Is Thomas Ahn enrolled in Medicare?

Yes. Thomas Ahn 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.

When was this NPI record last updated?

The NPPES record for Thomas Ahn was last updated on December 14, 2025. NPI Profile syncs weekly with the NPPES registry data releases published by CMS. This NPI record was last updated 7 months 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.