2026 NPPES data Urology Physician NPI 1821257924 M.D.
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WILLIAM KAO, M.D.

Urology Physician in LARGO, Maryland. 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
802
Medicare Part D claims · 305 beneficiaries · Urology Physician avg: 1K

What the federal data shows

WILLIAM KAO, M.D. filed 802 Medicare Part D claims in 2023 as a Urology Physician in LARGO, Maryland.

802
Part D claims, 2023
Likely
board-certified (heuristic)

Every figure on this page comes straight from federal CMS records (NPPES, Medicare Part D, MIPS, Open Payments) — no proprietary rating or editorial opinion is applied.

WILLIAM KAO, M.D.'s Medicare Part D volume vs every U.S. prescriber

Total Medicare Part D claims, 2023 — across all CMS prescribers nationally

802 Top 27% higher than 73% of 1,370,886 prescribers

0–200: 670,926 prescribers (49%). Below this entry. 200–400: 182,923 prescribers (13%). Below this entry. 400–600: 90,619 prescribers (7%). Below this entry. 600–800: 56,224 prescribers (4%). Below this entry. 800–1,000: 40,919 prescribers (3%). This entry sits in this band. 1,000–1,200: 31,827 prescribers (2%). Above this entry. 1,200–1,400: 26,224 prescribers (2%). Above this entry. 1,400–1,600: 21,710 prescribers (2%). Above this entry. 1,600–1,800: 19,072 prescribers (1%). Above this entry. 1,800–2,000: 16,451 prescribers (1%). Above this entry. 2,000–2,200: 213,991 prescribers (16%). Above this entry. This provider 0 2K+ every Part D prescriber (claims/yr), bucketed by value

Each bar is a band; taller bars hold more prescribers. The dashed line + filled bar mark this entry. Hover or tap any bar for its full count, share, and where it sits relative to this entry.

Source CMS Medicare Part D Prescriber Public Use File · 2023

Board certification likely (heuristic — not verified)

WILLIAM KAO, M.D. practices in an ABMS-board-eligible specialty and shows active CMS Medicare participation + 1 hospital affiliation — signals consistent with board-certified status. For verified board certification, see CertificationMatters.org (the official ABMS public lookup).

What does the federal data show about WILLIAM KAO, M.D.?

Quality data not reported

NPI registry status

Active

Issued 06/03/2008

NPI 1821257924

Primary specialty

Urology Physician

Mid-sized

13,350 US NPIs in this specialty

Medicare Part D claims

802 37% vs specialty avg

2023 prescription claims

Specialty avg: 1,280

Specialty distribution in Maryland

How Urology Physician compares to other specialties among Maryland providers

Maryland providers

Urology Physician share within Maryland

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

Specialty board-certification context

Estimated specialty board-certified rate — Urology Physician (ABMS / AOA reference)

Quality data not reported
Est. board-certified rate
78%
Urology Physician ABMS/AOA estimate

Est. board-certified rate (Urology Physician) — ABMS / AOA estimate

0%100%78%
Est. board-certified rate (Urology Physician) — ABMS / AOA estimate

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).

WILLIAM KAO, M.D. is a Urology Physician provider practicing in LARGO, Maryland, according to the CMS National Plan and Provider Enumeration System (NPPES). Credentials: M.D.. NPI: 1821257924. 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.

WILLIAM KAO, M.D. appears in the CMS NPPES registry as a Urology Physician provider holding M.D. credentials at 1221 MERCANTILE LN, LARGO, MD, 20774, with a listed phone of (301) 618-5633. NPI 1821257924 was issued on 06/03/2008. Because NPPES data is self-reported by the provider and refreshed monthly, the address, phone, and specialty reflect what KAO 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 802 prescription claims written by this provider, covering 305 Medicare beneficiaries and totaling roughly $23K in drug spend, with an opioid prescribing rate of 4.2%. 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.

Urology Physician is a mid-sized specialty nationwide, with 13,350 enrolled providers across 54 states and an average of 1,280 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

1221 MERCANTILE LN
LARGO, MD 20774

Provider Details

NPI 1821257924
Specialty Urology Physician
Credentials M.D.
Gender Male
NPI Issued 06/03/2008

Hospital and facility affiliations

Facilities where WILLIAM KAO, M.D. 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.

KAISER FOUNDATION HEALTH PLAN OF THE MID ATLANTIC STATES, INC
LARGO, MD

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

Medicare Part D Prescribing Data

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

802
Total Claims
$23K
Total Drug Cost
305
Medicare Beneficiaries

Prescribing Breakdown

30-Day Fills
1,939
Total Day Supply
54,522
Generic Drug Cost
$16K
Opioid Claims
34 (4.2% rate)
Antibiotic Claims
111

Patient Demographics

Average Patient Age
75.1 years
Avg HCC Risk Score
1.18
Gender Split
19% female / 81% male
Age Distribution
<65: 11, 65-74: 130, 75-84: 131, 85+: 33

Top Prescribed Drugs (Medicare Part D)

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

Drug Claims
Tamsulosin Hcl
260
Oxybutynin Chloride Er
Oxybutynin Chloride
113
Finasteride
97
Trospium Chloride
48
Sulfamethoxazole-Trimethoprim
Sulfamethoxazole/Trimethoprim
28
Levofloxacin
25
Tadalafil
20
Oxycodone Hcl
17
Tolterodine Tartrate Er
Tolterodine Tartrate
16
Nitrofurantoin Mono-Macro
Nitrofurantoin Monohyd/M-Cryst
15

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

Urology Physician Overview

How WILLIAM KAO, M.D. fits within the Urology Physician landscape nationally.

13,350
Urology Physician Providers in US
54
States with Urology Physician
1,280
Avg Claims per Provider

WILLIAM KAO, M.D.'s 802 claims are below the specialty average of 1,280.

Nearby Urology Physician Providers in Maryland

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

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

Frequently Asked Questions

What is WILLIAM KAO, M.D.'s specialty?
WILLIAM KAO, M.D. specializes in Urology Physician and practices in LARGO, Maryland. Credentials: M.D..
How much does WILLIAM KAO, M.D. prescribe under Medicare Part D?
In 2023, WILLIAM KAO, M.D. wrote 802 Medicare Part D claims totaling $23K in drug costs for 305 beneficiaries.
Where is WILLIAM KAO, M.D. located?
WILLIAM KAO, M.D. is located at 1221 MERCANTILE LN, LARGO, MD, 20774. Phone: (301) 618-5633.
What is WILLIAM KAO, M.D.'s NPI number?
WILLIAM KAO, M.D.'s National Provider Identifier (NPI) is 1821257924, issued on 06/03/2008.
Does WILLIAM KAO, M.D. prescribe opioids?
Yes, WILLIAM KAO, M.D. had 34 opioid claims in 2023 with an opioid prescribing rate of 4.2%.
How many Urology Physician providers are there in the US?
There are 13,350 Urology Physician providers across 54 states in the US. The average Urology Physician provider writes 1,280 Medicare Part D claims per year.
What drugs does WILLIAM KAO, M.D. prescribe most often?
Based on 2023 Medicare Part D data, WILLIAM KAO, M.D.'s most frequently prescribed drugs include Tamsulosin Hcl, Oxybutynin Chloride Er, Finasteride. This reflects Medicare Part D prescriptions only and does not include commercial insurance or other payer types.
Does WILLIAM KAO, M.D. accept Medicare?
WILLIAM KAO, M.D. appears in CMS Medicare data with 802 Part D claims and 305 Medicare beneficiaries in 2023. Contact the provider's office directly to confirm current Medicare enrollment and accepted plans.
How can I verify WILLIAM KAO, M.D.'s credentials?
WILLIAM KAO, M.D.'s NPI is 1821257924 with credentials M.D.. 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.
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