2026 NPPES data Hospitalist Physician NPI 1255951786 DO
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ANDREW DIAZ, DO

Hospitalist Physician in HUNTLEY, Illinois. CMS National Plan and Provider Enumeration System profile including specialty classification, practice address, and Medicare prescribing data when reported.

Federal data — no proprietary rating. PlainDoctor publishes the actual CMS NPPES and Medicare records — NPI registration, specialty, practice location, and prescribing data — without a composite score or editorial opinion on top. Every field traces to a federal source.
Prescribing volume
191
Medicare Part D claims · 64 beneficiaries · Hospitalist Physician avg: 888
MIPS score
94.1036/100
▲ 11 pts above national avg 83.1 · [object Object]
What the federal data reveals: ANDREW DIAZ, DO is a Hospitalist Physician ([object Object]) practicing in HUNTLEY, Illinois with a Medicare Part D prescribing footprint of 191 claims across 64 beneficiaries . Their CMS MIPS Final Score of 94.1036/100 (national average: 83.1) reflects performance across Quality, Cost, Interoperability, and Improvement Activities .

What stands out: ANDREW DIAZ, DO reported a CMS MIPS final score of 94.1036 out of 100, above the 83.1 national average, and filed 191 Medicare Part D claims in 2023. Every figure on this page comes straight from federal CMS records, with no proprietary rating applied.

Board certification likely (heuristic — not verified)

ANDREW DIAZ, DO practices in an ABMS-board-eligible specialty and shows active CMS Medicare participation + MIPS quality reporting + 1 hospital affiliation — signals consistent with board-certified status. For verified board certification, see CertificationMatters.org (the official ABMS public lookup).

ANDREW DIAZ, DO at a glance

High performer (top quartile)

NPI registry status

Active

Issued 04/24/2020

NPI 1255951786

Primary specialty

Hospitalist Physician

Mid-sized

16,825 US NPIs in this specialty

Medicare Part D claims

191 78% vs specialty avg

2023 prescription claims

Specialty avg: 888

MIPS final score

94.1036/100 11.003600000000006% pts

Exceptional band

vs 83.1 national avg

Specialty distribution in Illinois

How Hospitalist Physician compares to other specialties among Illinois providers

Illinois providers

Hospitalist Physician share within Illinois

1. Hospitalist Physician42%2. Internal medicine21%3. Family medicine17%4. Surgical12%5. Pediatric8%
Hospitalist Physician share within Illinois

Medicare quality performance — MIPS

ANDREW DIAZ, DO's 2023 MIPS final score plotted against the Hospitalist Physician national average

High performer (top quartile)
MIPS Final Score
94.1036/100
vs 83.1 national avg · 2023 performance year

MIPS final score (Hospitalist Physician) — 94.1036/100 vs national avg 83.1

0%100%National avg83%94.1%
MIPS final score (Hospitalist Physician) — 94.1036/100 vs national avg 83.1

The Merit-based Incentive Payment System (MIPS) scores providers 0–100 across four performance categories: Quality, Cost, Promoting Interoperability, and Improvement Activities, weighted under 42 CFR §414.1380. Reporting is voluntary for many small practices, so absence of a MIPS score is not a quality signal.

Board certification through an ABMS or AOA member board signals voluntary post-licensure examination plus continuous Maintenance of Certification cycles. Verify any individual provider's status through certificationmatters.org (ABMS) or osteopathic.org (AOA).

ANDREW DIAZ, DO is a Hospitalist Physician provider practicing in HUNTLEY, Illinois, according to the CMS National Plan and Provider Enumeration System (NPPES). Credentials: DO. NPI: 1255951786. This profile includes practice location, specialty classification, and organizational affiliations from the CMS provider registry. Provider information is self-reported to CMS and updated monthly.

ANDREW DIAZ, DO appears in the CMS NPPES registry as a Hospitalist Physician provider holding DO credentials at 10400 HALIGUS RD, HUNTLEY, IL, 60142, with a listed phone of (815) 759-4323. NPI 1255951786 was issued on 04/24/2020. Because NPPES data is self-reported by the provider and refreshed monthly, the address, phone, and specialty reflect what DIAZ most recently submitted to CMS rather than a vetted directory listing, which is why patients should always confirm the practice is still at this location before scheduling.

Medicare Part D records for calendar year 2023 show 191 prescription claims written by this provider, covering 64 Medicare beneficiaries and totaling roughly $16K in drug spend. These figures capture only Medicare Part D — commercial insurance, Medicaid, and cash-pay prescriptions are not included, and any drug-beneficiary cell under 11 is suppressed by CMS for patient privacy. On the CMS Merit-based Incentive Payment System, this provider earned a Final Score of 94.1036/100 for the 2023 performance year (Quality 82.5938), compared with the national average of 83.1.

Hospitalist Physician is a mid-sized specialty nationwide, with 16,825 enrolled providers across 54 states and an average of 888 Part D claims per prescriber, so the context for interpreting these metrics differs meaningfully from a primary-care baseline. Important: PlainDoctor is a directory of publicly available government data, not medical advice, a malpractice database, or a quality rating. Inclusion here does not imply a recommendation, and absence of complaints or sanctions on this page does not mean none exist — always verify credentials through the NPPES NPI Registry, your state medical board, and the ABMS or AOA before making healthcare decisions.

Practice Address

10400 HALIGUS RD
HUNTLEY, IL 60142

Provider Details

NPI 1255951786
Specialty Hospitalist Physician
Credentials DO
Gender Male
NPI Issued 04/24/2020

CMS Quality Score (MIPS)

Merit-based Incentive Payment System (MIPS) scores from CMS, 2023 performance year.

94.1036
Final Score
Avg: 83.1
82.5938
Quality
100
Promoting Interoperability

Reporting: Alternative Payment Model

Hospital and facility affiliations

Facilities where ANDREW DIAZ, DO bills Medicare from. Star ratings (1-5) are CMS Hospital Compare's "Hospital overall rating" — a composite of mortality, readmission, patient experience, safety, timely care, and efficient use of medical imaging measures. Source: CMS Care Compare.

NORTHWESTERN MEDICAL FACULTY FOUNDATION
HUNTLEY, IL

Affiliations sourced from CMS Doctors and Clinicians National Downloadable File; hospital ratings from CMS Hospital General Information dataset (cross-referenced by facility name + state).

License & disciplinary context — Illinois IDFPR 2023 annual report

Aggregate state board data only — NOT a determination of any individual provider's status. The figures below describe statewide disciplinary activity across all ~42K Illinois medical licensees in 2023 — they are NOT specific to ANDREW DIAZ, DO. To verify ANDREW DIAZ, DO's current license status, search the IDFPR public license lookup directly, or check the Federation of State Medical Boards (FSMB) verification service.

106
Total board actions, Illinois 2023
Across 103 cases
2.52
Actions per 1,000 licensees
Illinois statewide rate
probation
Most common action type
38 cases

IDFPR publishes annual disciplinary statistics as part of public-record reporting under each state's Administrative Procedure Act. See the full breakdown by action type and year on the Illinois disciplinary trends page. Cross-checked against FSMB U.S. Medical Regulatory Trends.

Medicare Part D Prescribing Data

CMS Medicare Part D prescriber-level data for calendar year 2023.

191
Total Claims
$16K
Total Drug Cost
64
Medicare Beneficiaries

Prescribing Breakdown

30-Day Fills
319
Total Day Supply
8,557
Generic Drug Cost
$2K
Antibiotic Claims
20

Patient Demographics

Average Patient Age
75.6 years
Avg HCC Risk Score
2.07
Gender Split
50% female / 50% male

Top Prescribed Drugs (Medicare Part D)

Top drugs by claim count for calendar year 2023. Based on Medicare Part D data only.

Drug Claims
Atorvastatin Calcium
13
Furosemide
12
Gabapentin
12

* Counts below 11 are suppressed by CMS for patient privacy. Generic names shown where available from CMS Part D data.

Hospitalist Physician Overview

How ANDREW DIAZ, DO fits within the Hospitalist Physician landscape nationally.

16,825
Hospitalist Physician Providers in US
54
States with Hospitalist Physician
888
Avg Claims per Provider

ANDREW DIAZ, DO's 191 claims are below the specialty average of 888.

Nearby Hospitalist Physician Providers in Illinois

Other clinicians with the same primary specialty enrolled in Illinois, drawn from the same CMS NPPES roster as DIAZ.

Compare Hospitalist Physician nationally: see state-by-state distribution →

Frequently Asked Questions

What is ANDREW DIAZ, DO's specialty?
ANDREW DIAZ, DO specializes in Hospitalist Physician and practices in HUNTLEY, Illinois. Credentials: DO.
How much does ANDREW DIAZ, DO prescribe under Medicare Part D?
In 2023, ANDREW DIAZ, DO wrote 191 Medicare Part D claims totaling $16K in drug costs for 64 beneficiaries.
What is ANDREW DIAZ, DO's Medicare quality score?
ANDREW DIAZ, DO has a CMS MIPS Final Score of 94.1036/100 (Quality: 82.5938). The national average MIPS Final Score is 83.1. Source: CMS Merit-based Incentive Payment System (MIPS) 2023.
Where is ANDREW DIAZ, DO located?
ANDREW DIAZ, DO is located at 10400 HALIGUS RD, HUNTLEY, IL, 60142. Phone: (815) 759-4323.
What is ANDREW DIAZ, DO's NPI number?
ANDREW DIAZ, DO's National Provider Identifier (NPI) is 1255951786, issued on 04/24/2020.
How many Hospitalist Physician providers are there in the US?
There are 16,825 Hospitalist Physician providers across 54 states in the US. The average Hospitalist Physician provider writes 888 Medicare Part D claims per year.
What drugs does ANDREW DIAZ, DO prescribe most often?
Based on 2023 Medicare Part D data, ANDREW DIAZ, DO's most frequently prescribed drugs include Atorvastatin Calcium, Furosemide, Gabapentin. This reflects Medicare Part D prescriptions only and does not include commercial insurance or other payer types.
Does ANDREW DIAZ, DO accept Medicare?
ANDREW DIAZ, DO appears in CMS Medicare data with 191 Part D claims and 64 Medicare beneficiaries in 2023. Contact the provider's office directly to confirm current Medicare enrollment and accepted plans.
How can I verify ANDREW DIAZ, DO's credentials?
ANDREW DIAZ, DO's NPI is 1255951786 with credentials DO. You can verify this through the NPPES NPI Registry, check state medical board records, and confirm board certification through the ABMS or AOA.

Data Sources

Provider Directory
CMS National Plan and Provider Enumeration System (NPPES), download.cms.gov/nppes, updated monthly. Contains NPI, specialty, credentials, and practice location.
Specialty Classification
NUCC Health Care Provider Taxonomy (nucc.org), the industry standard for classifying provider specialties in Medicare and Medicaid billing.
Prescribing Data
CMS Medicare Part D Prescriber Public Use File (2023). Includes claims, drug costs, beneficiaries, and opioid prescribing rates.
Quality Performance
CMS Merit-based Incentive Payment System (MIPS) — 2023 performance year.
Limitations
Provider data is self-reported to CMS. Prescribing data reflects Medicare Part D only and does not include commercial insurance, Medicaid, or cash prescriptions. Claims below 11 beneficiaries are suppressed by CMS for privacy.

See our complete data methodology for details on how we collect and process government data.

Data as of April 2026 (NPPES) / 2023 (Medicare Part D). Source: Centers for Medicare & Medicaid Services (CMS).

Disclaimer: Data from CMS NPPES and Medicare Part D. PlainDoctor does not rate or rank providers. Provider information is self-reported and may not be current. Always verify information directly with the provider. About · Methodology