Recently Updated NPI Information — some details in this NPI profile have been updated in the NPI registry within the last 60 days.

DR. GUNNLAUGUR PETUR NIELSEN MD
NPI 1174592653
Pathology - Anatomic Pathology in Boston, MA

Q: What is Gunnlaugur Nielsen's NPI number?

The NPI number for Gunnlaugur Nielsen is 1174592653. It was assigned to this individual provider in the NPPES registry on March 16, 2006.

Q: What is Gunnlaugur Nielsen's specialty?

The primary specialty registered for this NPI is Pathology, specializing in Anatomic Pathology, with taxonomy code 207ZP0101X.

Active since March 16, 2006PECOS Enrolled

55 FRUIT ST WRN 2, PATHOLOGY ASSOCIATES, BOSTON, MA 02114(617) 724-1469(617) 726-9312 Get Directions Write a Review

NPPES record last updated: July 13, 2026. Verified against the NPPES registry weekly; last sync: August 02, 2026.

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About Dr. Gunnlaugur Petur Nielsen Md NPPES

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

DR. GUNNLAUGUR PETUR NIELSEN MD (NPI 1174592653) is an individual anatomic pathology provider in Boston, Massachusetts, licensed in Massachusetts (78780) and active in the NPI registry since March 2006. He is enrolled in Medicare PECOS, is affiliated with Massachusetts General Hospital, and maintains a secondary practice location in Boston.

NPPES Registry Identity

NPI1174592653

Entity TypeIndividualMale

Primary Taxonomy207ZP0101X

Provider Legal NameDR. GUNNLAUGUR PETUR NIELSENCredential: MD

Location Address55 FRUIT ST WRN 2, PATHOLOGY ASSOCIATESBoston, MA 02114-2696

Mailing AddressPo Box 9142, Mass General Physician OrganizationCharlestown, MA 02129-9142 · (617) 724-0287 · Fax (617) 726-2894

Phone(617) 724-1469

Fax(617) 726-9312

Sole ProprietorNo

Medical School CMSOtherGraduated 1988

Enumeration DateMarch 16, 2006

Last NPPES UpdateJuly 13, 2026

NPPES CertifiedJune 12, 2026

✔ NPI 1174592653 is a valid, active identifier and passes the ISO check-digit test.

Specialties & Licenses

★ Primary SpecialtyPathology · Anatomic PathologyAllopathic & Osteopathic Physicians

Taxonomy Code207ZP0101X

License✔ Licensed in MA · 78780

Definition

A pathologist deals with the causes and nature of disease and contributes to diagnosis, prognosis and treatment through knowledge gained by the laboratory application of the biologic, chemical and physical sciences. A pathologist uses information gathered from the microscopic examination of tissue specimens, cells and body fluids, and from clinical laboratory tests on body fluids and secretions for the diagnosis, exclusion and monitoring of disease.

55 FRUIT ST WRN 2, Boston, MA 02114

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Secondary Practice Location 1

Location 175 Francis StBoston, MA 02115-6110 · Phone (617) 732-5500

Other Identifiers 3

Medicaid3124584MA

OtherJ30551MA · Bcbs Ma

Other078780MA · Tufts Health Plan

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. Gunnlaugur Petur Nielsen 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 ID1052342987

PECOS Enrollment IDI20050830000684

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.

Preparation of tissue for examination by removing any calcium present 88311

This procedure involves treating tissue samples to remove any calcium, which can interfere with the examination. The tissue is soaked in a special solution that safely dissolves the calcium, leaving the tissue intact for accurate analysis. This helps in making precise diagnoses.

512 services440 patients

Pathology examination of tissue using a microscope, intermediate complexity 88305

A pathology examination of tissue with intermediate complexity involves studying a small sample of your body tissue under a microscope. This helps in identifying any abnormal cells or signs of disease. It's a detailed process requiring expert analysis to ensure accurate results.

356 services314 patients

Special stained specimen slides to examine tissue, each additional procedure 88341

Special stained specimen slides are used to analyze tissue in detail. In this process, extra procedures may be needed for a more thorough examination. These involve applying special stains to the tissue on slides, enhancing specific elements for closer study.

318 services79 patients

Pathology examination of tissue using a microscope, moderately low complexity 88304

A pathology examination of tissue, moderately low complexity, involves studying a small sample of your body tissue under a microscope. It helps to identify any abnormal cells or diseases. It's a routine procedure, not complex, and provides crucial insights for your diagnosis.

288 services257 patients

Pathology examination of tissue using a microscope, moderately high complexity 88307

A pathology examination of tissue with moderate complexity involves a detailed study of a small tissue sample from your body. Using a microscope, experts analyze the tissue's structure and cells to identify any abnormalities. This helps in diagnosing various health conditions accurately.

262 services189 patients

Pathology examination of specimen during surgery, first tissue block 88331

A pathology examination during surgery involves the immediate analysis of a removed tissue sample. This helps the surgeon make decisions during your operation. The "first tissue block" refers to the initial sample examined. It's a vital step to ensure your health.

192 services119 patients

Special stained specimen slides to examine tissue, initial procedure 88342

This procedure involves the use of specially stained slides to examine tissue samples. The initial process involves obtaining a small tissue sample from your body. This sample is then placed on a slide and stained with special dyes to highlight different structures and elements. The stained slide is then examined under a microscope to help diagnose any potential health issues.

100 services94 patients

Surgical pathology consultation and report on referred slides prepared elsewhere 88321

A surgical pathology consultation involves reviewing slides prepared at a different lab to confirm or clarify a diagnosis. It's a second opinion to ensure accuracy. A report with findings and interpretations is then provided for your doctor's reference.

34 services34 patients

Pathology examination of specimen during surgery, each additional tissue block 88332

During surgery, a pathology examination may be done on additional tissue blocks. This involves taking small samples of tissue and examining them under a microscope. This helps identify any abnormal cells or diseases present, aiding in the precise diagnosis and treatment planning.

34 services16 patients

Pathology examination of tissue using a microscope, high complexity 88309

A high complexity pathology examination involves studying body tissue under a microscope to identify any abnormalities. This intricate process helps in diagnosing various conditions and deciding on the best treatment plan.

31 services30 patients

Microscopic genetic analysis of tumor, manual 88360

Microscopic genetic analysis of a tumor involves examining your tumor's genes under a microscope. This helps identify specific genetic changes in the tumor cells. This information can aid in diagnosing, predicting disease progression, and determining the most effective treatment options.

28 services15 patients

Pathology examination of tissue using a microscope 88302

A pathology examination of tissue involves studying a small sample of your body's cells under a microscope. This helps identify any abnormalities or diseases, such as cancer. The process is crucial for accurate diagnosis and treatment planning.

22 services22 patients

Special stained specimen slides to examine tissue including interpretation and report 88313

Special stained specimen slides are used to examine tissue samples. This involves applying special dyes to the tissue, which helps to highlight certain features under a microscope. The findings are then interpreted and a report is provided. This can aid in diagnosing various health conditions.

22 services17 patients

Hospital Affiliations CMS Care Compare 3

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

Massachusetts General Hospital

Acute Care Hospitals · Boston, MA

5/5 CMS rating

OwnershipVoluntary non-profit - Private

CMS Certification Number220071

Location55 Fruit StreetBoston, MA 02114 · Suffolk County

Emergency services Birthing friendly

Massachusetts Eye And Ear Infirmary -

Acute Care Hospitals · Boston, MA

OwnershipVoluntary non-profit - Private

CMS Certification Number220075

Location243 Charles StreetBoston, MA 02114 · Suffolk County

Emergency services

Martha's Vineyard Hospital Inc

Critical Access Hospitals · Oak Bluffs, MA

4/5 CMS rating

OwnershipVoluntary non-profit - Private

CMS Certification Number221300

LocationOne Hospital Road, First Fl, Wing 5, PO Box 1477Oak Bluffs, MA 02557 · Dukes County

Emergency services Birthing friendly

Physician Visit Costs CMS claims · ZIP area

Typical Medicare office-visit costs in the 02114 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

$144.11 typical visit price

range $63.72 – $189.86

Typical copayment $36.02 (range $15.93 – $47.46)

Most-billed visit code 99204

Established Patient

$111.18 typical visit price

range $21.07 – $155.29

Typical copayment $27.79 (range $5.26 – $38.82)

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.

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 Gunnlaugur Nielsen's NPI number?

The NPI number for Gunnlaugur Nielsen is 1174592653. It was assigned to this individual provider in the NPPES registry on March 16, 2006.

Where is Gunnlaugur Nielsen located?

Gunnlaugur Nielsen practices at 55 Fruit St Wrn 2 Pathology Associates, Boston, MA 02114. The listed phone number is (617) 724-1469.

What is Gunnlaugur Nielsen's specialty?

The primary specialty registered for this NPI is Pathology, specializing in Anatomic Pathology, with taxonomy code 207ZP0101X.

Is Gunnlaugur Nielsen enrolled in Medicare?

Yes. Gunnlaugur Nielsen 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.

Is Gunnlaugur Nielsen affiliated with any hospitals?

According to CMS data, Gunnlaugur Nielsen is affiliated with Massachusetts General Hospital, Massachusetts Eye And Ear Infirmary - and Martha's Vineyard Hospital Inc.

When was this NPI record last updated?

The NPPES record for Gunnlaugur Nielsen was last updated on July 13, 2026. NPI Profile syncs weekly with the NPPES registry data releases published by CMS. This NPI record was last updated 25 days 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.