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Allergy/Immunology

Rajashri S. Iyengar, MD

Sees patients in San Mateo, CA · Burlingame, CA · San Carlos, CA … · California

Summary

Dr. Rajashri S. Iyengar, MD is an allergist and immunologist at 123 S San Mateo Dr, San Mateo, CA 94401. Phone: (650) 343-4200. Accepts Medicare assignment. In 2024, Rajashri S. Iyengar had 148 Original Medicare patients and 7,774 services. NPI 1811004476. Source: CMS National Downloadable File, updated October 2, 2026; CMS Medicare Physician & Other Practitioners, data year 2024.

  • Specialty: Allergist and immunologist (Medicare lists Allergy/Immunology)
  • Address: 123 S San Mateo Dr, San Mateo, CA 94401 · Directions (3 more locations)
  • Phone: (650) 343‑4200
  • Medicare: Accepts Medicare assignment
  • Group practice: Sutter Bay Medical Foundation
  • Medical school: Duke University School Of Medicine · graduated 2002 (24 years since medical school)
  • Gender (as listed): Female
  • Telehealth: offered

From official Medicare data

This page shows what Medicare's official clinician data says about Rajashri S. Iyengar, 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 Rajashri S. Iyengar accept Medicare assignment?
Yes. Medicare's clinician data says Rajashri S. Iyengar 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 Rajashri S. Iyengar see?
In 2024, CMS data shows 148 Original Medicare patients and 7,774 services for Rajashri S. Iyengar. This counts Original Medicare only and measures volume, not quality.
What is Rajashri S. Iyengar's NPI number?
1811004476. 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 Rajashri S. Iyengar, 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 patients148
Services billed to Medicare7,774
Different services or procedures15
Participating Medicare providerYes
Average age of these patients72

Most frequent services

  1. Test for allergy using allergenic extract (95004)1,219 services
  2. Professional service for preparation and provision of 1 or more antigens (95165)930 services
  3. Professional service for multiple injections of allergen (95117)753 services
  4. Established patient office or other outpatient visit with moderate level of decision making, if using time, 30 minutes or more (99214)153 services
  5. Established patient office or other outpatient visit with high level of medical decision making, if using time, 40 minutes or more (99215)46 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 cholesterol73%
  • High blood pressure56%
  • Asthma47%
  • Arthritis42%
  • Osteoporosis28%
  • Anxiety20%

Practice locations

Addresses where Rajashri S. Iyengar is enrolled with Medicare (CMS data updated October 2, 2026).

Group practices

Medicare enrollment lists Rajashri S. Iyengar as a member of this group (CMS data updated October 2, 2026).

  • Sutter Bay Medical Foundation3,829 clinicians in the group

Specialties

Find other Allergy/Immunology doctors in California →

Other allergist and immunologists in San Mateo

Clinicians with the same Medicare primary specialty in San Mateo, CA — not a recommendation.

All allergist and immunologists in San Mateo →

Other clinicians in Sutter Bay Medical Foundation

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

Clinician information

CredentialMD
Medical schoolDuke University School Of Medicine
Graduation year2002 (24 years since medical school)
Gender (as listed)Female
Medicare assignmentAccepts (Medicare-approved amount as full payment)
TelehealthOffers telehealth services
NPI (National Provider Identifier)1811004476
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