DR. KARTHIK GUNACHELVAN
NPI 1740604941
Internal Medicine in Darien, CT

Q: What is Karthik Gunachelvan's NPI number?

The NPI number for Karthik Gunachelvan is 1740604941. It was assigned to this individual provider in the NPPES registry on February 7, 2014.

Q: What is Karthik Gunachelvan's specialty?

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

Active since February 07, 2014PECOS EnrolledAccepts Medicare Assignment

1500 POST RD STE 100, DARIEN, CT 06820(203) 655-8749(203) 656-0701 Get Directions Write a Review

NPPES record last updated: October 21, 2025. Verified against the NPPES registry weekly; last sync: August 16, 2026.

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About Dr. Karthik Gunachelvan NPPES

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

DR. KARTHIK GUNACHELVAN (NPI 1740604941) is an individual internal medicine provider in Darien, Connecticut, licensed in Connecticut (82825) and active in the NPI registry since February 2014. He is enrolled in Medicare PECOS, is affiliated with Mercy Medical Ctr, and is a graduate of Other (2013).

NPPES Registry Identity

NPI1740604941

Entity TypeIndividualMale

Primary Taxonomy207R00000X

Provider Legal NameDR. KARTHIK GUNACHELVAN

Location Address1500 POST RD STE 100Darien, CT 06820-5936

Mailing Address1500 Post Rd Ste 100Darien, CT 06820-5936 · (203) 655-8749 · Fax (203) 656-0701

Phone(203) 655-8749

Fax(203) 656-0701

Sole ProprietorYes

Medical School CMSOtherGraduated 2013

Enumeration DateFebruary 7, 2014

Last NPPES UpdateOctober 21, 2025

NPPES CertifiedOctober 21, 2025

✔ NPI 1740604941 is a valid, active identifier and passes the ISO check-digit test.

Specialties & Licenses

★ Primary SpecialtyInternal MedicineAllopathic & Osteopathic Physicians

Taxonomy Code207R00000X

License✔ Licensed in CT · 82825

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.

1500 POST RD STE 100, Darien, CT 06820

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Accepted Insurance

The full list of accepted plans is on the Insurance tab. Issuers include Anthem Blue Cross and Blue Shield.Insurance ›

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. Karthik Gunachelvan 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 ID6103104211

PECOS Enrollment IDI20161025000455, I20251125002150

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 13

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.

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.

813 services377 patients

Office or other outpatient visit for the evaluation and management of established patient that may not require presence of healthcare professional 99211

This service involves an outpatient visit for established patients who may not need direct interaction with a healthcare professional. It could include reviewing test results, monitoring existing conditions, or adjusting treatment plans. It's typically done remotely, ensuring your comfort and convenience.

219 services35 patients

Annual wellness visit, includes a personalized prevention plan of service (pps), subsequent visit G0439

An annual wellness visit is a yearly appointment with your primary care provider to create or update a personalized prevention plan. This plan helps prevent illness based on your current health and risk factors. It's a subsequent visit, meaning it follows an initial assessment.

169 services169 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.

105 services86 patients

Administration of influenza virus vaccine G0008

The administration of the influenza virus vaccine, also known as the flu shot, is a simple procedure to protect against the flu. A healthcare provider injects a small dose of the vaccine into your arm. This stimulates your immune system to produce antibodies, which will help your body fight off the flu if exposed.

66 services65 patients

Influenza vaccine, inactivated 90653

The Influenza vaccine, inactivated, is a shot given to protect against the flu. It contains killed virus particles that help your body build immunity to the flu. It's recommended annually to keep your protection up-to-date. It's safe for ages 6 months and up.

57 services57 patients

Physician or allowed practitioner certification for medicare-covered home health services under a home health plan of care (patient not present), including contacts with home health agency and review of reports of patient status required by physicians and G0180

This is a service where a doctor or authorized practitioner certifies that you require Medicare-covered home health services. They will communicate with the home health agency and review reports on your health status to ensure you receive appropriate care. This does not involve an in-person visit.

48 services42 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.

38 services15 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.

37 services34 patients

Pneumococcal conjugate vaccine, 20 valent (pcv20), for intramuscular use 90677

The Pneumococcal Conjugate Vaccine (PCV20) is a shot given to protect against 20 types of bacteria that can cause serious infections like pneumonia and meningitis. It's administered through a muscle, usually in the arm. It's important for overall health.

23 services23 patients

Annual wellness visit; includes a personalized prevention plan of service (pps), initial visit G0438

An annual wellness visit is a yearly appointment with your doctor to create or update a personalized prevention plan. This plan helps prevent illness based on your current health and risk factors. It's an opportunity to discuss your health status and goals and get a plan tailored for you.

19 services19 patients

Physician or allowed practitioner re-certification for medicare-covered home health services under a home health plan of care (patient not present), including contacts with home health agency and review of reports of patient status required by physicians a G0179

This procedure involves a doctor or approved practitioner reviewing your health status and re-certifying your need for Medicare-covered home health services. It includes communication with the home health agency and assessment of your health reports, even when you're not physically present.

18 services14 patients

Administration of pneumococcal vaccine G0009

The pneumococcal vaccine helps protect against pneumococcal bacteria, which can cause severe infections like pneumonia and meningitis. The vaccine is given as an injection, typically in the arm. It's recommended for infants, older adults, and those with certain health conditions.

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.

Mercy Medical Ctr

Acute Care Hospitals · Springfield, MA

3/5 CMS rating

OwnershipVoluntary non-profit - Private

CMS Certification Number220066

Location271 Carew StreetSpringfield, MA 01104 · Hampden County

Emergency services Birthing friendly

Baystate Medical Center

Acute Care Hospitals · Springfield, MA

1/5 CMS rating

OwnershipVoluntary non-profit - Private

CMS Certification Number220077

Location759 Chestnut StreetSpringfield, MA 01199 · Hampden County

Emergency services Birthing friendly

Physician Visit Costs CMS claims · ZIP area

Typical Medicare office-visit costs in the 06820 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

$138.84 typical visit price

range $60.82 – $183.10

Typical copayment $34.71 (range $15.20 – $45.77)

Most-billed visit code 99204

Established Patient

$106.68 typical visit price

range $19.76 – $149.26

Typical copayment $26.67 (range $4.94 – $37.31)

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.

Referred Medical Equipment & Supplies CMS DME claims 5

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

17 suppliers50 claims148 services$6.11 avg. paid by Medicare

Lancets, per box of 100 A4259

DME-Medical/Surgical Supplies · category DA000N

13 suppliers23 claims42 services$1.03 avg. paid by Medicare

Hospital bed, semi-electric (head and foot adjustment), with any type side rails, without mattress E0261

DME-Hospital Beds · category DB000N

1 supplier11 claims11 services$33.58 avg. paid by Medicare

Transport chair, adult size, patient weight capacity up to and including 300 pounds E1038

DME-Other DME · category DE000N

1 supplier12 claims12 services$6.15 avg. paid by Medicare

Pharmacy dispensing fee for inhalation drug(s); per 30 days Q0513

DME-Other DME · category DE000N

5 suppliers13 claims13 services$20.13 avg. paid by Medicare

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

Other Providers at the Same Location NPPES

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

MARGARET BARAN

Internal Medicine

1500 POST RD STE 100
DARIEN, CT 06820

Western Connecticut Planning Region (203) 655-8749

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 Karthik Gunachelvan's NPI number?

The NPI number for Karthik Gunachelvan is 1740604941. It was assigned to this individual provider in the NPPES registry on February 7, 2014.

Where is Karthik Gunachelvan located?

Karthik Gunachelvan practices at 1500 Post Rd Ste 100, Darien, CT 06820. The listed phone number is (203) 655-8749.

What is Karthik Gunachelvan's specialty?

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

Is Karthik Gunachelvan enrolled in Medicare?

Yes. Karthik Gunachelvan 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.

What insurance does Karthik Gunachelvan accept?

Health plans from Anthem Blue Cross and Blue Shield list Karthik Gunachelvan 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 Karthik Gunachelvan affiliated with any hospitals?

According to CMS data, Karthik Gunachelvan is affiliated with Mercy Medical Ctr and Baystate Medical Center.

When was this NPI record last updated?

The NPPES record for Karthik Gunachelvan was last updated on October 21, 2025. NPI Profile syncs weekly with the NPPES registry data releases published by CMS. This NPI record was last updated 10 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.