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Recently Updated NPI Information — some details in this NPI profile have been updated in the NPI registry within the last 30 days.

MARK J SARNAK M.D.
NPI 1982641502
Internal Medicine - Nephrology in Boston, MA

Active since June 01, 2006PECOS Enrolled
750 WASHINGTON ST, TUFTS- NEW ENGLAND MEDICAL CENTER, BOSTON, MA 02111(617) 636-5866 Get Directions Write a Review

NPPES record last updated: July 13, 2026. Verified against the NPPES registry weekly; last sync: July 26, 2026.

About Mark J Sarnak M.d. NPPES

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

MARK J SARNAK M.D. (NPI 1982641502) is an individual nephrology provider in Boston, Massachusetts, licensed in Massachusetts (82001) and active in the NPI registry since June 2006. He is enrolled in Medicare PECOS, is affiliated with Tufts Medical Center, and is a graduate of Columbia University College Of Physicians And Surgeons (1993).

NPPES Registry Identity

NPI1982641502
Entity TypeIndividualMale
Primary Taxonomy207RN0300X
Provider Legal NameMARK J SARNAKCredential: M.D.
Location Address750 WASHINGTON ST, TUFTS- NEW ENGLAND MEDICAL CENTERBoston, MA 02111-1526
Mailing Address750 Washington St, Tufts- New England Medical Center Box 391Boston, MA 02111-1526 · (617) 636-5866
Phone(617) 636-5866
Sole ProprietorNo
Medical School CMSColumbia University College Of Physicians And SurgeonsGraduated 1993
Enumeration DateJune 1, 2006
Last NPPES UpdateJuly 13, 2026
✔ NPI 1982641502 is a valid, active identifier and passes the ISO check-digit test.

Specialties & Licenses

★ Primary SpecialtyInternal Medicine · NephrologyAllopathic & Osteopathic Physicians
Taxonomy Code207RN0300X
License✔ Licensed in MA · 82001
Definition
An internist who treats disorders of the kidney, high blood pressure, fluid and mineral balance and dialysis of body wastes when the kidneys do not function. This specialist consults with surgeons about kidney transplantation.
750 WASHINGTON ST, Boston, MA 02111
Open in Google Maps ↗

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

Mark J Sarnak M.d. 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 ID7618169434
PECOS Enrollment IDI20101011001169
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 5

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.

Subsequent hospital care with moderate levelof medical decision making, if using time, at least 35 minutes 99232
Follow-up hospital inpatient care involves daily check-ups while you're admitted in the hospital. Typically, a healthcare provider spends about 25 minutes each day reviewing your condition, adjusting treatment if needed, and answering any questions you might have.
116 services54 patients
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.
112 services62 patients
Subsequent hospital care with moderate levelof medical decision making, if using time, at least 50 minutes 99233
Follow-up hospital inpatient care per day typically involves a 35-minute check-up by your healthcare provider. This service includes monitoring your health progress, adjusting your treatment plan if needed, and answering any questions you may have about your condition or care.
73 services42 patients
Initial hospital care with straightforward or low-level medical decision making, if using time, at least 55 minutes 99222
Initial hospital inpatient care is a service where a healthcare provider spends about 50 minutes per day overseeing your care while you're admitted in the hospital. This includes reviewing your health status, planning your treatment, and ensuring your safety and comfort.
19 services19 patients
Initial hospital care with moderate level of medical decision making, if using time, at least 75 minutes 99223
Initial hospital inpatient care per day, typically 70 minutes, refers to the daily medical service provided to patients admitted to the hospital. This includes a comprehensive evaluation, diagnosis, treatment plan, and monitoring of your health condition. It ensures your well-being during your hospital stay.
18 services18 patients

Hospital Affiliations CMS Care Compare

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

Tufts Medical Center

Acute Care Hospitals · Boston, MA
3/5 CMS rating
OwnershipVoluntary non-profit - Private
CMS Certification Number220116
Location800 Washington StreetBoston, MA 02111 · Suffolk County
Emergency services Birthing friendly

Physician Visit Costs CMS claims · ZIP area

Typical Medicare office-visit costs in the 02111 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.

Referred Medical Equipment & Supplies CMS DME claims 3

Durable medical equipment, devices and supplies this provider ordered from DME suppliers for patients, from Medicare fee-for-service claims.

Tacrolimus, immediate release, oral, 1 mg J7507
Treatment-Treatment - Miscellaneous · category RX029N
2 suppliers12 claims960 services$0.35 avg. paid by Medicare
Pharmacy supply fee for oral anti-cancer, oral anti-emetic or immunosuppressive drug(s); for the first prescription in a 30-day period Q0511
Treatment-Chemotherapy · category RH012N
3 suppliers20 claims20 services$18.11 avg. paid by Medicare
Pharmacy supply fee for oral anti-cancer, oral anti-emetic or immunosuppressive drug(s); for a subsequent prescription in a 30-day period Q0512
Treatment-Chemotherapy · category RH012N
3 suppliers15 claims16 services$11.87 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 20

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

KEIKO UEDA MPH, RD, LDN
Dietitian, Registered
750 WASHINGTON ST, TNEMC BOX#434
BOSTON, MA 02111
Suffolk County (617) 636-5458
COLLEEN MCARTOR CRNA
Nurse Anesthetist, Certified Registered
750 WASHINGTON ST, NEMC BOX #7105
BOSTON, MA 02111
Suffolk County (617) 636-5000
DR. KATHLEEN BUNGAY PHARMD, MS
Pharmacist (Psychiatric)
750 WASHINGTON ST, THE HEALTH INSTITUTE, BOX 345
BOSTON, MA 02111
Suffolk County (617) 636-3292
ALEXIS MADEJ M.S., R.D., L.D.N.
Dietitian, Registered
750 WASHINGTON ST, FRANCES STERN NUTRITION CENTER
BOSTON, MA 02111
Suffolk County (617) 636-5273
DR. NADINE YOUSSEF M.D.
Emergency Medicine
750 WASHINGTON ST, BOX 311 / DEPARTMENT OF EMERGENCY MEDICINE
BOSTON, MA 02111
Suffolk County (617) 636-4723
DR. GORDON M SAPERIA MD
Internal Medicine (Interventional Cardiology)
750 WASHINGTON ST
BOSTON, MA 02111
Suffolk County (617) 636-5000
ANBUKILI K. CHETTY M.D.
Pediatrics (Pediatric Pulmonology)
750 WASHINGTON ST, NEMC BOX #836
BOSTON, MA 02111
Suffolk County (617) 636-5000
KATIE WAKELEY M.D.
Obstetrics & Gynecology
750 WASHINGTON ST, NEMC BOX #836
BOSTON, MA 02111
Suffolk County (617) 636-5000

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 Mark Sarnak's NPI number?

The NPI number for Mark Sarnak is 1982641502. It was assigned to this individual provider in the NPPES registry on June 1, 2006.

Where is Mark Sarnak located?

Mark Sarnak practices at 750 Washington St Tufts- New England Medical Center, Boston, MA 02111. The listed phone number is (617) 636-5866.

What is Mark Sarnak's specialty?

The primary specialty registered for this NPI is Internal Medicine, specializing in Nephrology, with taxonomy code 207RN0300X.

Is Mark Sarnak enrolled in Medicare?

Yes. Mark Sarnak 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 Mark Sarnak accept?

Health plans from Anthem Blue Cross and Blue Shield list Mark Sarnak 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 Mark Sarnak affiliated with any hospitals?

According to CMS data, Mark Sarnak is affiliated with Tufts Medical Center.

When was this NPI record last updated?

The NPPES record for Mark Sarnak was last updated on July 13, 2026. NPI Profile syncs with the weekly NPPES data releases published by CMS.