David Leff

Cross-source identity

Sources that publish this NPI

National Provider Identifier 1619956505 appears in the source rows shown below. Sources that do not publish NPI use their own identifiers and are not treated as deterministic NPI matches. Chips show response-supplied dates when available; otherwise they are labeled date unavailable.

Industry payments

Open Payments received

Payments and transfers of value this clinician received from drug and device manufacturers, disclosed under the Physician Payments Sunshine Act. A payment is a disclosure, not a judgment.

Prescribing

Medicare Part D prescribing

Prescriptions written under Medicare Part D, aggregated by drug across the program. Totals reflect claims paid, not patients treated.

Beneficiary counts below 11 are suppressed by CMS — the total shown is a lower bound.

Enrollment & sanctions

Standing

Ownership & affiliations

Who owns, operates, or is affiliated with this provider

Chain membership, ownership, and operating relationships from federal records — each one backed by a government source row. Most individual clinicians have none; owners and organizations carry more.

Record history

Retained versions for this record

This view shows dated claim versions only when this NPI has a retained coordinate in the provenance store. Most facts have no superseded version, so an arbitrary past date may return no prior row. Source and recorded dates appear when present.

Related research & the graph

Context for this record

Studies that contextualize the federal data on this profile, and the canonical entity node behind NPI 1619956505 in the resolved graph.

• Open Payments / Sunshine Act →
  How industry payments concentrate across specialties and manufacturers.
• Medicare provider enrollment →
  Who is enrolled to bill Medicare, by provider type, across the national file.
• All Fonteum research →
  Studies built on the same federal records, each with its sources attached.