What is Margarita Castro-Zarraga's specialty?

Margarita Castro-Zarraga (NPI 1578705679) is a Medicare-billing provider whose primary specialty is Family Practice in Lowell, MA.

Where does Margarita Castro-Zarraga practice?

Margarita Castro-Zarraga practices in Lowell, MA, based on the location reported in the CMS Medicare provider datasets for NPI 1578705679.

How much does Medicare pay Margarita Castro-Zarraga?

Margarita Castro-Zarraga (NPI 1578705679) received approximately $960 in total Medicare Part B payments, serving 31 beneficiaries, per the CMS Medicare Physician & Other Practitioners dataset.

PROVIDER PROFILE · NPI 1578705679

Margarita Castro-ZarragaM.D.

PRACTICED.A.W., L.L.C.See all providers at this practice →

Family PracticeLowell, MAI

MEDICARE UTILIZATION · PART B · 2024

Total beneficiaries

Unique beneficiaries

—

Total services

Distinct HCPCS

Medicare payment

$305

Peer benchmark

Total Medicare services vs. 1,348 Family Practice providers in MA — bottom quintile (cohort median 537).

PRESCRIBING · PART D · 2024

Total Rx claims

3,445

Beneficiaries

—

Total drug cost

$435K

Distinct drugs

Brand share

27.3%

Top prescribed drugs

Atorvastatin Calcium326 claims

Amlodipine Besylate203 claims

Albuterol Sulfate185 claims

Gabapentin179 claims

Lisinopril161 claims

QUALITY · MIPS · 2024

No data available for this provider in 2024.

INDUSTRY PAYMENTS · OPEN PAYMENTS · 2025

Total received

$63

Payment records

By payment type

Food and Beverage$63

Top paying entities

Food and Beverage$63

REFERRAL NETWORK

Where Margarita Castro-Zarraga's patients come from & go

Directional shared-patient flow from Medicare claims — who sends patients to this provider (inbound) and where this provider's patients go next (outbound). 48 inbound referrers · 0 outbound destinations.

Receives referrals from

Inbound — who sends patients here

Physician	Patients	Visits
BETH ISRAEL DEACONESS HOSPITAL-NEEDHAM, INC.	163	2,088
NEWBRIDGE ON THE CHARLES, INC.	142	667
BRIARWOOD OPERATOR, LLC	110	1,005
FALLON SERVICE, INC.	108	609
Perminder Dhillon Internal Medicine · Needham, MA	74	426
Alexis Kelleher Nurse Practitioner · Roslindale, MA	58	470
FALLON EMERGENCY MEDICAL SERVICES, INC.	49	238
SULLIVAN, MARYELLEN	43	357
Quest Diagnostics Massachusetts Llc Clinical Laboratory · Marlborough, MA	37	109
Bruce Kaster Geriatric Psychiatry · Needham, MA	31	121
NI MHUIRCHEARTAIGH, JENNIFER	29	130
VIJAYAKUMAR, RADHA	28	306

Refers patients to

Outbound — where patients go next

No outbound pairs above the suppression threshold.

Source: CMS Physician Shared Patient Patterns (30-day window, Medicare FFS). Direction = a beneficiary seen by the first provider, then the second, within 30 days; a proxy for referral, not a documented referral. Pairs with fewer than 11 shared beneficiaries are suppressed.

CROSS-REFERENCE

Related data on other Healthparse brands

ProviderScore

OIG/SAM exclusion screening, sanctions history

Healthparse Signals

Monitor this provider for changes — dated NPI change events