ZACHARY THOMAS FELLOWS M.D.
NPI 1154733152
Internal Medicine - Rheumatology in Carlsbad, CA


Quality Rating: 80.73 out of 100 score

NPI Status: Active since May 24, 2014

Contact Information

6120 PASEO DEL NORTE STE L2
CARLSBAD, CA
ZIP 92011
Phone: (760) 891-4687
Fax: (760) 684-8715

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  • Individual
  • Male
  • Years of Experience 12
  • Internal Medicine
  • Rheumatology
  • Accepts Medicare Approved Payment
  • PECOS Enrolled
  • Medicare Quality Reporting

About ZACHARY FELLOWS

This page provides the complete NPI Profile along with additional information for Zachary Fellows, an internist established in Carlsbad, California with a medical specialization in Internal Medicine, focusing in rheumatology and more than 12 years of experience. The healthcare provider is registered in the NPI registry with number 1154733152 assigned on May 2014. The practitioner's primary taxonomy code is 207RR0500X with license number A144510 (CA). The provider is registered as an individual and his NPI record was last updated January 2026.

NPI
1154733152
Provider Name
ZACHARY THOMAS FELLOWS M.D.
Gender
Male
Entity Type
Individual
Location Address
6120 PASEO DEL NORTE STE L2 CARLSBAD, CA 92011
Location Phone
(760) 891-4687
Location Fax
(760) 684-8715
Mailing Address
6120 PASEO DEL NORTE STE L2 CARLSBAD, CA 92011
Mailing Phone
(760) 891-4687
Mailing Fax
(760) 684-8715
Medical School Name
OTHER
Graduation Year
2014
Is Sole Proprietor?
No
Enumeration Date
05-24-2014
Last Update Date
01-18-2026
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An internist like Zachary Fellows 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

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 Rheumatology

Taxonomy Code
207RR0500X
Type
Allopathic & Osteopathic Physicians
License No.
A144510
License State
CA
Taxonomy Description
An internist who treats diseases of joints, muscle, bones and tendons. This specialist diagnoses and treats arthritis, back pain, muscle strains, common athletic injuries and collagen diseases.

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

A144510 (CA)
2207RB0002XAllopathic & Osteopathic Physicians

Internal Medicine
Obesity Medicine

A144510 (CA)

Medicare Participation & PECOS Enrollment Status

Zachary Fellows 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.

Zachary Fellows 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: 941580708

    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: I20200619001047

    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

Areas of Expertise

The following services and procedures, recently provided to Medicare patients, illustrate the range of care this provider offers. This list reflects the variety of services available to all patients visiting the practice and is based on 2022 Medicare dataset. In general, the more frequently a provider treats specific conditions or performs particular procedures, the more experienced they become in addressing similar patient needs. The provider has delivered many of the services listed below to Medicare patients. Please note that this list does not include services provided to patients who are not covered by Medicare.

Aspiration and/or injection of fluid from large joint

This procedure involves using a needle to remove (aspiration) or introduce (injection) fluid into a large joint like the knee or hip. It can help diagnose conditions, relieve discomfort, or deliver medication directly to the joint.

This service was performed 40 times for 29 patients

Aspiration and/or injection of fluid from medium joint

This procedure involves a needle being inserted into a medium-sized joint, such as a knee or shoulder, to remove (aspirate) excess fluid. Sometimes, medication may also be injected into the joint to reduce inflammation and pain.

This service was performed 15 times for 14 patients

Aspiration and/or injection of fluid from medium joint using ultrasound guidance

This is a procedure where a needle is guided by ultrasound into a medium-sized joint, like a knee or shoulder. The needle can be used to remove fluid, which can relieve pressure and pain, or to inject medication to help with inflammation and discomfort.

This service was performed 18 times for 14 patients

Aspiration and/or injection of fluid from small joint

This procedure involves inserting a thin needle into a small joint to remove (aspirate) or inject fluid. It can help diagnose conditions, relieve discomfort, or administer medication directly into the joint. It's generally safe with minimal discomfort.

This service was performed 45 times for 24 patients

Aspiration and/or injection of fluid from small joint using ultrasound guidance

This procedure involves using ultrasound to accurately locate a small joint. A needle is then carefully inserted to remove fluid (aspiration) or inject medication. This can help diagnose or treat joint issues. It's generally safe and minimally invasive.

This service was performed 29 times for 21 patients

Aspiration and/or injection of fluid large joint using ultrasound guidance

This procedure involves using ultrasound technology to accurately locate a large joint, usually the knee or shoulder. A needle is then inserted to either extract fluid (aspiration) or inject medication. The ultrasound helps ensure precision and safety.

This service was performed 21 times for 17 patients

Dxa bone density measurement of hip, pelvis, spine

A DXA bone density measurement is a simple, quick, and non-invasive procedure that assesses the strength of your bones. This test uses X-rays to measure the amount of minerals, mainly calcium, in the hip, pelvis, and spine. It helps in early detection of osteoporosis or other bone diseases.

This service was performed 12 times for 12 patients

Established patient office or other outpatient visit, 30-39 minutes

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.

This service was performed 770 times for 301 patients

Established patient office or other outpatient visit, 40-54 minutes

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.

This service was performed 44 times for 33 patients

Infusion into a vein for therapy, prevention, or diagnosis, 1 hour or less

This is a procedure where a medical professional inserts a small tube into your vein to deliver medication, nutrients, or fluids directly into your bloodstream. This can be for treatment, prevention, or diagnosis. The process typically takes less than an hour.

This service was performed 114 times for 26 patients

Injection, golimumab, 1 mg, for intravenous use

Golimumab is a medication given through an IV (a small tube in your vein). It helps to reduce inflammation and pain by blocking a protein in your body that causes inflammation. It's often used to treat conditions like rheumatoid arthritis, psoriatic arthritis, and ankylosing spondylitis.

This service was performed 10,950 times for 16 patients

Injection, triamcinolone acetonide, not otherwise specified, 10 mg

Triamcinolone acetonide is a medication used to reduce inflammation in the body. It's given as a 10 mg injection for conditions like allergies, arthritis, or skin problems. The injection helps to decrease swelling, redness, and itching.

This service was performed 466 times for 98 patients

Limited ultrasound scan of joint or other extremity structure lacking blood vessels

A limited ultrasound scan of a joint or other extremity structure lacking blood vessels is a non-invasive procedure that uses sound waves to create images of the inside of your body. This helps in diagnosing and monitoring conditions related to your joints or other similar structures.

This service was performed 86 times for 69 patients

New patient office or other outpatient visit, 60-74 minutes

This is a first-time patient visit where a healthcare professional spends 60-74 minutes with you. It involves a comprehensive evaluation, including your medical history and current health condition. They'll also advise on preventive health measures and formulate a treatment plan if needed.

This service was performed 95 times for 95 patients

Telephone medical discussion with physician, 11-20 minutes

This is a service where you have a phone conversation with your doctor for 11-20 minutes. It's used for discussing health concerns, reviewing test results, or managing ongoing conditions. It's a convenient way to receive medical advice without an in-person visit.

This service was performed 72 times for 55 patients

Telephone medical discussion with physician, 21-30 minutes

This service involves a 21-30 minute phone conversation with a physician. It's a chance for you to discuss your health concerns, symptoms or treatment plans. It's similar to an in-person consultation, but conducted over the phone for your convenience and safety.

This service was performed 23 times for 15 patients

Physician Visit Costs



The typical physician office visit costs for Medicare beneficiaries in this area are: $35.05 for a new patient copayment and $27.1 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 92011 ZIP code area.

New Patients Visit Costs *

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

  • Average New Patient Price $140.22
  • Minimum New Patient Price $62.1
  • Maximum New Patient Price $184.71
  • Average New Patient Copayment $35.05
  • Minimum New Patient Copayment $15.52
  • Maximum New Patient Copayment $46.17

Established Patients Visit Costs *

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

  • Average Established Patient Price $108.42
  • Minimum Established Patient Price $20.62
  • Maximum Established Patient Price $151.42
  • Average Established Patient Copayment $27.1
  • Minimum Established Patient Copayment $5.15
  • Maximum Established Patient Copayment $37.85

* 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.

Overall MIPS Quality Performance

The provider participated in CMS Quality Payment Program under the Merit-based Incentive Payment System (MIPS) and has an overall final score of 80.73, based on four performance areas: quality, improvement activities, promoting interoperability, and cost. The purpose of this information is to help people with Medicare make informed decisions and incentivize doctors and clinicians to maximize performance. The provider also has detailed performance information the following quality measures: .

The Merit-based Incentive Payment System (MIPS) is a way providers could use to participate in CMS Quality Payment Program (QPP). The MIPS program affects clinician reimbursement for Part B covered professional services and also rewards them for improving the quality of patient care and outcomes.

  • Final Score: 80.73 out of 100

    The MIPS program evaluates providers across multiple categories with a specific weight for each category resulting a in a MIPS final score that ranges from 0 to 100 points. The MIPS Final Score determines whether providers receive a negative, neutral or positive MIPS payment adjustment.

  • Quality Score: 80.22

    The Quality category assesses providers performance on clinical practices and patient outcomes under the traditional MIPS program. The quality measures help identify the quality of healthcare processes, outcomes, and patient experiences. The Quality measure category compromises 40% providers final MPIS scores.

    There are six collection types for MIPS quality measures: Electronic Clinical Quality Measures (eCQMs), MIPS Clinical Quality Measures (CQMs), Qualified Clinical Data Registry (QCDR) Measures, Medicare Part B claims measures, CMS Web Interface measures and The Consumer Assessment of Healthcare Providers and Systems (CAHPS) for MIPS Survey.

  • Promoting Interoperability Score: 100

    The Interoperability category measures the providers ability to use technology to exchange and make use of healthcare information in a way that is less burdensome and improves outcomes. The Interoperability measure category compromises 25% providers final MPIS scores.

    The MIPS Interoperability measure focuses on the use of certified electronic health record technology (CEHRT) to improve patient access health information, the exchange of information between clinicians and pharmacies and the systematic collection, analysis, and interpretation of healthcare data.

  • Improvement Activities Score: 40

    The Improvement Activities performance category evaluates the providers participation in clinical activities that support the improvement of clinical practice, care delivery, and outcomes. Providers have the option to choose 2 to 4 activities from an inventory of over 100 improvement activities. Providers typically choose the activities that best fit their needs. The improvement activities measure category compromises 15% providers final MPIS scores.

    The Improvement measures aim to better patient engagement, patient safety and other areas of patient care. The Improvement Activities category compromises 15% of providers final MPIS scores.

  • Cost Score: 55.54

    The Cost performance category asses the amount and types of services provided and how clinicians coordinate care and seek improvement of health outcomes by ensuring patients receive the appropriate services.

    Although providers don't determine the price of healthcare services they are important in delivering high-quality care at a reasonable cost. The Cost measures category compromises 20% of providers final MPIS scores.

  • Cost Score: 55.54

    The Cost performance category asses the amount and types of services provided and how clinicians coordinate care and seek improvement of health outcomes by ensuring patients receive the appropriate services.

    Although providers don't determine the price of healthcare services they are important in delivering high-quality care at a reasonable cost. The Cost measures category compromises 20% of providers final MPIS scores.

MIPS Quality Measures

The following performance measures were reported under the Merit-Based Incentive Payment System (MIPS) and Qualified Clinical Data Registry (QCDR) quality measures program.

Quality Measure Performance Number of Patients
Documentation of Current Medications in the Medical Record 100% 3097
Gout: Serum Urate Target 54% 35
Hepatitis B Safety Screening 68% 76
Provide Patients Electronic Access to Their Health Information 92% 604
Safe Hydroxychloroquine Dosing 76% 159
Screening for Osteoporosis for Women Aged 65-85 Years of Age 51% 228
Tuberculosis Screening Prior to First Course of Biologic and/or Immune Response Modifier Therapy 93% 55

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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 1154733152, we treat the final digit (2) 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 48. The final step is to find the difference between that total and the next multiple of ten (50 - 48 = 2).

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
1
Unchanged
Pos 3
5
Doubled → 10 → 1 + 0
Pos 4
4
Unchanged
Pos 5
7
Doubled → 14 → 1 + 4
Pos 6
3
Unchanged
Pos 7
3
Doubled → 6
Pos 8
1
Unchanged
Pos 9
5
Doubled → 10 → 1 + 0
Check
2
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 5 → 10 → 1 7 → 14 → 5 3 → 6 5 → 10 → 1

Step 2: Add all digits plus the NPI constant

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

2 + 1 + 1 + 0 + 4 + 1 + 4 + 3 + 6 + 1 + 1 + 0 + 24 = 48

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

The next multiple of ten after 48 is 50. The difference is the calculated check digit.

50 - 48 = 2
This NPI is valid
The calculated check digit is 2, which matches the last digit of 1154733152.

Other Providers at the Same Location


The following 2 providers are registered at the same or a nearby location.

Registered Nurse
6120 PASEO DEL NORTE STE L2
CARLSBAD, CA 92011
Internal Medicine (Rheumatology)
6120 PASEO DEL NORTE STE L2
CARLSBAD, CA 92011

Frequently Asked Questions

The NPI number assigned to this healthcare provider is 1154733152, enumerated as an "individual" on May 24, 2014.

The provider is located at 6120 PASEO DEL NORTE STE L2 CARLSBAD, CA 92011 and the phone number is (760) 891-4687.

Internal Medicine with taxonomy code 207RR0500X and a focus in Rheumatology.