Dr. Gunnlaugur Nielsen, MD
What this data tells you about Dr. Nielsen
Dr. Gunnlaugur Nielsen is an anatomic pathology physician in Boston, MA, with 20 years of NPI registration. Based on federal Medicare data, Dr. Nielsen performed 2,247 Medicare services in 2023. These records do not provide a deduplicated patient total.
The Data Coverage level for Dr. Nielsen is High — reflecting how much public federal data is available about this provider. Patients are encouraged to use this data as one of several factors when choosing a healthcare provider.
Medicare Practice Summary — 2023
Medicare Utilization ↗Top procedures by volume
Ranked by number of services performed for Medicare patients. Avg. submitted charge is what the provider billed; avg. Medicare payment is what CMS paid.
| Procedure | Volume | Avg. paid | Avg. submitted |
|---|---|---|---|
| Tissue preparation to remove calcium A laboratory procedure that removes calcium from a tissue sample to prepare it for microscopic examination. |
543 | $10 | $51 |
| Tissue pathology examination, moderate complexity A laboratory test where a pathologist examines tissue samples under a microscope to analyze cellular details. This intermediate complexity procedure involves specialized techniques to identify abnormalities in the tissue. |
411 | $31 | $153 |
| Tissue staining for diagnosis, additional An extra laboratory procedure to apply special stains to tissue slides for detailed examination. |
298 | $24 | $115 |
| Pathology tissue examination, moderate complexity A laboratory test where a pathologist examines tissue samples under a microscope to identify abnormalities. This specific level indicates a moderate degree of complexity in the analysis. |
267 | $9 | $61 |
| Moderately high complexity pathology tissue examination A laboratory test where a pathologist examines tissue samples under a microscope to analyze cellular details. This specific level of complexity involves a moderate to high degree of technical skill and interpretation. |
243 | $69 | $339 |
| Intraoperative pathology examination, first tissue block A pathologist examines a tissue sample removed during surgery to provide a preliminary diagnosis. This test is performed on the first tissue block obtained from the procedure. |
195 | $51 | $256 |
| Tissue staining for diagnosis, initial A laboratory test where special stains are applied to tissue slides to help examine the cells and identify specific characteristics. |
100 | $29 | $205 |
| Additional surgical pathology tissue block This code covers the pathology examination of each additional tissue block processed during surgery. It is billed for each extra specimen block analyzed beyond the initial one. |
54 | $26 | $125 |
| Manual microscopic genetic analysis of tumor A laboratory test that uses a microscope to manually examine tumor tissue for genetic changes. |
39 | $35 | $225 |
| Surgical pathology consultation on referred slides A pathologist reviews and reports on tissue slides that were prepared at another facility. This service provides a second opinion or expert analysis of the existing samples. |
35 | $70 | $344 |
| Special tissue stain and interpretation A laboratory test using special stains to examine tissue samples, including the pathologist's review and written report of the findings. |
22 | $10 | $49 |
| Microscopic tissue examination A pathologist examines a tissue sample under a microscope to identify abnormalities or disease. |
21 | $5 | $28 |
| High complexity pathology tissue examination A laboratory test where a pathologist examines tissue samples under a microscope using advanced techniques to analyze cellular details. |
19 | $122 | $597 |
Geographic Context
0.0 mi
Data Sources
| Provider Registry | ✓ NPPES | NPPES snapshot; verify current record |
| Medicare Enrollment | ✓ PECOS | PECOS snapshot |
| Practice Data | ✓ Medicare Util. | Annual (CY lag) |
| Industry Payments | — No payments | N/A |
| Disciplinary History | — Not included | N/A |
This provider has data in 3 of 4 available federal datasets, with a Data Coverage level of High. This reflects how much public data is available about a provider. How we calculate this →
Summary
Dr. Nielsen is a mixed practice specialist, with above-average Medicare volume (top 21% in MA), with 20 years of NPI registration.
This summary is auto-generated from federal data, describing data availability and patterns. Read our methodology →
Frequently Asked Questions
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This page combines public CMS records with calculated summaries and explanatory procedure labels. These transformations are not verbatim federal records. Sources: NPPES ↗, Medicare Provider Utilization ↗, and PECOS. Publication is mandated by the Physician Payments Sunshine Act (§6002 ACA, 42 U.S.C. §1320a-7h) and the Freedom of Information Act.
This page is not medical advice, an endorsement, a recommendation, or a quality rating. Data Coverage reflects data completeness — how much federal information exists for this provider — not clinical performance, patient outcomes, or quality of care. Always verify information directly with the provider and consult a licensed clinician before making medical decisions.
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