MALLORY SIN LDN, RD
NPI 1821426826
Dietitian, Registered in Boston, MA
About Mallory Sin Ldn, Rd NPPES
Official registry information on file with the National Plan and Provider Enumeration System.
MALLORY SIN LDN, RD (NPI 1821426826) is an individual dietitian, registered in Boston, Massachusetts, licensed in Massachusetts (1076733) and active in the NPI registry since October 2013. She is affiliated with Beth Israel Deaconess Medical Center, maintains a secondary practice location in Roxbury, and is a graduate of Other (2012).
NPPES Registry Identity
Specialties & Licenses
Secondary Practice Location 1
Medicare Participation & PECOS CMS
Medicare enrollment, assignment, billing reassignment, and ordering and referring status from CMS.
Medicare Enrollment Status
Enrolled in Medicare and accepts Medicare assignment
Mallory Sin Ldn, Rd 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.
Medicare Billing Reassignments
2Medicare enrollment records show Mallory Sin reassigns Medicare billing to 2 organizations. Each organization bills Medicare for the services this provider delivers there; the nearest is listed first.
Boston, MA 02215
- Reassigned Medicare billing, Massachusetts enrollment
- 125 clinicians in this Medicare group
Dedham, MA 02026
- Reassigned Medicare billing, Massachusetts enrollment
- 5 clinicians in this Medicare group
Source: CMS Revalidation Reassignment List, October 2026 release. Reassignment records can lag staffing changes; confirm a current affiliation with the organization.
Areas of Expertise CMS Part B claims
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.
Hospital Affiliations CMS Care Compare
Hospitals where this provider delivers care, identified from recent Medicare claims and place-of-service records.
Beth Israel Deaconess Medical Center
Acute Care Hospitals · Boston, MAPhysician Visit Costs CMS claims · ZIP area
Typical Medicare office-visit costs in the 02215 ZIP code area, from fee-for-service claims. These are area statistics, not this provider’s prices; actual charges vary by service and coverage.
Other Providers at the Same Location NPPES 6
Providers registered at the same practice address, or within the immediate area, according to the NPPES registry.
BOSTON, MA 02215
BOSTON, MA 02215
BOSTON, MA 02215
BOSTON, MA 02215
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 Mallory Sin's NPI number?
The NPI number for Mallory Sin is 1821426826. It was assigned to this individual provider in the NPPES registry on October 29, 2013.
Where is Mallory Sin located?
Mallory Sin practices at One Joslin Place, Boston, MA 02215. The listed phone number is (917) 825-0376.
What is Mallory Sin's specialty?
The primary specialty registered for this NPI is Dietitian, Registered with taxonomy code 133V00000X.
Is Mallory Sin enrolled in Medicare?
Yes. Mallory Sin 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.
Which organizations bill Medicare for Mallory Sin's services?
According to the CMS Revalidation Reassignment List (October 2026 release), Mallory Sin reassigns Medicare benefits to 2 organizations: Joslin Clinic Inc (Boston, MA) and Alisonrd LLC (Dedham, MA). Each reassignment is filed with Medicare on form CMS-855R, signed by both the clinician and the organization, and lets the organization bill Medicare and receive payment for Mallory Sin's services. Reassignment records can lag staffing changes; confirm current arrangements with the organization.
Is Mallory Sin affiliated with any hospitals?
According to CMS data, Mallory Sin is affiliated with Beth Israel Deaconess Medical Center.
When was this NPI record last updated?
The NPPES record for Mallory Sin was last updated on November 27, 2018. NPI Profile syncs weekly with the NPPES registry data releases published by CMS. This NPI record was last updated 7 years 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.
# Mallory Sin, LDN, RD · NPI 1821426826
Dietitian, Registered provider in Boston, Massachusetts. Individual provider, active in the CMS NPPES registry since October 29, 2013.
## Identity
- **NPI:** 1821426826 (Entity type: Individual)
- **Enumerated:** October 29, 2013
- **Primary specialty:** Dietitian, Registered · taxonomy 133V00000X
- **State license:** 1076733 (Massachusetts)
- **Sole proprietor:** No
## Practice location
- **Address:** ONE JOSLIN PLACE, Boston, MA 02215-3432
- **Phone:** (917) 825-0376
## Medicare
- **Medicare:** Enrolled (PECOS); accepts Medicare assignment
- **Bills Medicare through:** 2 organizations under Medicare reassignment (form CMS-855R): Joslin Clinic Inc (NPI 1528003621, Boston, MA); Alisonrd LLC (NPI 1891221834, Dedham, MA) · CMS Revalidation Reassignment List, October 2026 release
- **Medical school:** Other, class of 2012
## Record status
- **NPPES last updated:** November 27, 2018
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Source: [NPI Profile](https://npiprofile.com/npi/1821426826) · Data from the CMS NPPES public registry.