ALEX DIAZ D.O.
NPI 1659759363
Internal Medicine - Pulmonary Disease in San Ramon, CA

Q: What is Alex Diaz's NPI number?

The NPI number for Alex Diaz is 1659759363. It was assigned to this individual provider in the NPPES registry on May 13, 2015.

Q: What is Alex Diaz's specialty?

The primary specialty registered for this NPI is Internal Medicine, specializing in Pulmonary Disease, with taxonomy code 207RP1001X.

Q: When was this NPI record last updated?

The NPPES record for Alex Diaz was last updated on September 8, 2021. NPI Profile syncs weekly with the NPPES registry data releases published by CMS. This NPI record was last updated 5 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.

Active since May 13, 2015PECOS EnrolledAccepts Medicare Assignment

5401 NORRIS CANYON RD STE 306, SAN RAMON, CA 94583(925) 866-8822 Get Directions Write a Review

NPPES record last updated: September 8, 2021. Verified against the NPPES registry weekly; last sync: November 01, 2026.

Record update history: Sep 8, 2021, Dec 6, 2018, Oct 12, 2016 (3 updates tracked since 2016).

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About Alex Diaz D.o. NPPES

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

ALEX DIAZ D.O. (NPI 1659759363) is an individual pulmonary disease provider in San Ramon, California, licensed in California (20A18649) and active in the NPI registry since May 2015. He is enrolled in Medicare PECOS and is a graduate of Other (2015).

NPPES Registry Identity

NPI1659759363

Entity TypeIndividualMale

Primary Taxonomy207RP1001X

Provider Legal NameALEX DIAZCredential: D.O.

Location Address5401 NORRIS CANYON RD STE 306San Ramon, CA 94583-5408

Mailing Address5401 Norris Canyon Rd Ste 308San Ramon, CA 94583-5408 · (925) 866-8822

Phone(925) 866-8822

Sole ProprietorYes

Medical School CMSOtherGraduated 2015

Enumeration DateMay 13, 2015

Last NPPES UpdateSeptember 8, 20213 updates tracked since enumeration

NPPES CertifiedSeptember 8, 2021

✔ NPI 1659759363 is a valid, active identifier and passes the ISO check-digit test.

Specialties & Licenses 2

★ Primary SpecialtyInternal Medicine · Pulmonary DiseaseAllopathic & Osteopathic Physicians

Taxonomy Code207RP1001X

License✔ Licensed in CA · 20A18649

Definition

An internist who treats diseases of the lungs and airways. The pulmonologist diagnoses and treats cancer, pneumonia, pleurisy, asthma, occupational and environmental diseases, bronchitis, sleep disorders, emphysema and other complex disorders of the lungs.

Also ListedStudent in an Organized Health Care Education/Training ProgramTaxonomy 390200000X

5401 NORRIS CANYON RD STE 306, San Ramon, CA 94583

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Other Identifiers 1

Medicaid1659759363CO

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

Alex Diaz D.o. 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 ID6608292313

PECOS Enrollment IDI20210921000801

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.

Medicare Billing Reassignments

Medicare enrollment records show Alex Diaz reassigns Medicare billing to 2 organizations. Each organization bills Medicare for the services this provider delivers there; the nearest is listed first.

Alex R Diaz Inc

Same address

Clinic/Center

5401 NORRIS CANYON RD STE 308
San Ramon, CA 94583

Reassigned Medicare billing, California enrollment

NPI 1760246284 (925) 866-8822

Elmont Community Health Center

2,563 mi

Clinic/Center

161 HEMPSTEAD TPKE
Elmont, NY 11003

Reassigned Medicare billing, New York enrollment
Medicare enrollment name: Nassau Health Care Corporation
553 clinicians in this Medicare group

NPI 1467478362 (516) 571-8200

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 12

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 nursing facility care with straightforward level of medical decision making, per day, if using time, 20 minutes or more 99308

A follow-up nursing facility visit per day is a daily check-up service provided by healthcare professionals. It lasts around 15 minutes and involves assessing your health status, monitoring your recovery progress, and addressing any concerns you may have about your health or treatment.

809 services70 patients

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.

219 services89 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.

208 services95 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.

148 services79 patients

Hospital discharge day management, more than 30 minutes 99239

Hospital discharge day management over 30 minutes involves a detailed process to ensure a smooth transition from hospital to home. It includes final examinations, discussion of your hospital stay, post-discharge instructions, and coordinating follow-up care.

130 services123 patients

Critical care, first 30-74 minutes 99291

Critical care involves immediate and constant attention by a team of specially-trained health professionals. It's for patients with life-threatening conditions, requiring first 30-74 minutes of intense monitoring and treatment.

127 services50 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.

112 services108 patients

New patient office or other outpatient visit with moderate level of medical decision making, if using time, 45 minutes or more 99204

This is a first-time office or outpatient visit lasting between 45-59 minutes. The healthcare provider evaluates your health, discusses your medical history, and may suggest further tests or treatments. It's an opportunity to ask questions and understand your health better.

56 services56 patients

Established patient office or other outpatient visit with low level od decision making, if using time, 20 minutes or more 99213

This is a routine visit for patients who have already been seen by the healthcare provider. During this approximately 20-29 minute appointment, your health status will be evaluated and any necessary treatments or tests will be discussed. It's a chance to address any health concerns you may have.

52 services41 patients

Test to measure expiratory airflow and volume changes before and after medication administration 94060

This procedure measures how air flows in and out of your lungs. It's done before and after medication to see if the treatment improves your breathing. It's a simple, non-invasive test that involves breathing into a device called a spirometer.

51 services49 patients

Test to determine lung volumes using sensors 94726

This test, called spirometry, measures lung capacity using sensors. You breathe into a mouthpiece attached to a device that records the amount and rate of air you inhale and exhale. It helps diagnose and monitor lung conditions.

51 services49 patients

Test to examine how well the lungs exchange gases 94729

This is a test called a pulmonary function test, which helps understand the efficiency of your lungs. It measures how much air your lungs can hold, how quickly you can move air in and out of your lungs, and how well your lungs put oxygen into and remove carbon dioxide from your blood.

51 services49 patients

Physician Visit Costs CMS claims · ZIP area

Typical Medicare office-visit costs in the 94583 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

$153.83 typical visit price

range $69.00 – $202.35

Typical copayment $38.45 (range $17.25 – $50.58)

Most-billed visit code 99204

Established Patient

$119.48 typical visit price

range $23.44 – $166.46

Typical copayment $29.87 (range $5.86 – $41.61)

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.

Walker, folding, wheeled, adjustable or fixed height E0143

DME-Other DME · category DE000N

2 suppliers13 claims13 services$42.76 avg. paid by Medicare

Portable gaseous oxygen system, rental; includes portable container, regulator, flowmeter, humidifier, cannula or mask, and tubing E0431

DME-Oxygen and Supplies · category DC000N

2 suppliers17 claims17 services$14.92 avg. paid by Medicare

Oxygen concentrator, single delivery port, capable of delivering 85 percent or greater oxygen concentration at the prescribed flow rate E1390

DME-Oxygen and Supplies · category DC002N

4 suppliers37 claims37 services$65.92 avg. paid by Medicare

Dollar amounts are the average Medicare paid the supplier per service. They are not the cost to the patient.

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 Alex Diaz's NPI number?

The NPI number for Alex Diaz is 1659759363. It was assigned to this individual provider in the NPPES registry on May 13, 2015.

Where is Alex Diaz located?

Alex Diaz practices at 5401 Norris Canyon Rd Ste 306, San Ramon, CA 94583. The listed phone number is (925) 866-8822.

What is Alex Diaz's specialty?

The primary specialty registered for this NPI is Internal Medicine, specializing in Pulmonary Disease, with taxonomy code 207RP1001X.

Is Alex Diaz enrolled in Medicare?

Yes. Alex Diaz 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 Alex Diaz's services?

According to the CMS Revalidation Reassignment List (October 2026 release), Alex Diaz reassigns Medicare benefits to 2 organizations: Alex R Diaz Inc (San Ramon, CA) and Elmont Community Health Center (Elmont, NY). 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 Alex Diaz's services. Reassignment records can lag staffing changes; confirm current arrangements with the organization.

When was this NPI record last updated?

The NPPES record for Alex Diaz was last updated on September 8, 2021. NPI Profile syncs weekly with the NPPES registry data releases published by CMS. This NPI record was last updated 5 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.