Medical emergency?Emergency? Call 911. Nearest emergency roomsNearest ERs

Internal Medicine

Zachary C. Liao, MD

Sees patients in Boston, MA · Massachusetts

Summary

Dr. Zachary C. Liao, MD is an internal medicine doctor at 133 Brookline Ave, Boston, MA 02215. Phone: (617) 421-1000. Accepts Medicare assignment. In 2024, Zachary C. Liao had 78 Original Medicare patients and 719 services. NPI 1538692207. Source: CMS National Downloadable File, updated October 2, 2026; CMS Medicare Physician & Other Practitioners, data year 2024.

  • Specialty: Internal medicine doctor (Medicare lists Internal Medicine)
  • Address: 133 Brookline Ave, Boston, MA 02215 · Directions
  • Phone: (617) 421‑1000
  • Medicare: Accepts Medicare assignment
  • Group practice: Atrius Health Inc
  • Medical school: University Of Washington School Of Medicine · graduated 2017 (9 years since medical school)
  • Gender (as listed): Male
  • Telehealth: offered

From official Medicare data

This page shows what Medicare's official clinician data says about Zachary C. Liao, joined by NPI number (data updated October 2, 2026). It is not a recommendation or a rating. Call the office or hospital to confirm before you go.

In a medical emergency, call 911.

Quick answers

Does Zachary C. Liao accept Medicare assignment?
Yes. Medicare's clinician data says Zachary C. Liao accepts Medicare assignment (the Medicare-approved amount as full payment for covered services), as of October 2, 2026. Ask the office to confirm before your visit.
How many Medicare patients does Zachary C. Liao see?
In 2024, CMS data shows 78 Original Medicare patients and 719 services for Zachary C. Liao. This counts Original Medicare only and measures volume, not quality.
What is Zachary C. Liao's NPI number?
1538692207. The NPI (National Provider Identifier) is the clinician's permanent federal ID; you can look it up in the official NPI Registry.

Medicare activity in 2024

Official CMS public-use data for Zachary C. Liao, data year 2024 (released May 21, 2026). It covers Original Medicare (fee-for-service) patients only, not Medicare Advantage or other insurance. It shows volume, not quality or outcomes. CMS hides any count of 10 or fewer patients.

Original Medicare patients78
Services billed to Medicare719
Different services or procedures84
Participating Medicare providerYes
Average age of these patients75

Most frequent services

  1. Insertion of needle into vein for collection of blood sample (36415)105 services
  2. Established patient office or other outpatient visit with low level od decision making, if using time, 20 minutes or more (99213)50 services
  3. Established patient office or other outpatient visit with moderate level of decision making, if using time, 30 minutes or more (99214)42 services
  4. Hemoglobin a1c level (83036)40 services
  5. Blood test, lipids (cholesterol and triglycerides) (80061)37 services

Chronic conditions among these patients

Share of this clinician’s Original Medicare patients with each condition, as published by CMS (it describes the patients, not the care given).

  • High blood pressure67%
  • High cholesterol55%
  • Diabetes28%
  • Chronic kidney disease27%
  • Arthritis24%
  • Ischemic heart disease24%

Practice locations

Addresses where Zachary C. Liao is enrolled with Medicare (CMS data updated October 2, 2026).

Group practices

Medicare enrollment lists Zachary C. Liao as a member of this group (CMS data updated October 2, 2026).

  • Atrius Health Inc1,222 clinicians in the group

Specialties

Find other Internal Medicine doctors in Massachusetts →

Other internal medicine doctors in Boston

Clinicians with the same Medicare primary specialty in Boston, MA — not a recommendation.

All internal medicine doctors in Boston →

Other clinicians in Atrius Health Inc

Medicare enrollment lists these clinicians in the same group practice — not a recommendation.

Clinician information

CredentialMD
Medical schoolUniversity Of Washington School Of Medicine
Graduation year2017 (9 years since medical school)
Gender (as listed)Male
Medicare assignmentAccepts (Medicare-approved amount as full payment)
TelehealthOffers telehealth services
NPI (National Provider Identifier)1538692207
CorrectionsReport an error or suggest an update →

Most corrections must be made at the source: clinicians update their NPI Registry record (NPPES) and their Medicare enrollment (PECOS); this page follows the next data release.

Sources

  1. National Downloadable File (Doctors and Clinicians) — CMS, data updated October 2, 2026, retrieved October 29, 2026
  2. Medicare Physician & Other Practitioners - by Provider — CMS, data year 2024, released May 21, 2026; Medicare Physician & Other Practitioners - by Provider and Service
  3. NPI Registry — U.S. Department of Health and Human Services (NPPES), the clinician’s official record
  4. Medicare Care Compare — official Medicare tool to look up clinicians