2026 NPPES data Emergency Medicine Physician NPI 1871673830 MD
Verify on CMS →

JOHN CHAFOS, MD

Emergency Medicine Physician in GREEN BROOK, New Jersey. 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
4K
Medicare Part D claims · 560 beneficiaries · Emergency Medicine Physician avg: 352
Generic prescribing
89%
generic claims · 11% brand-name · higher generic rates reduce patient out-of-pocket costs

What the federal data shows

JOHN CHAFOS, MD filed 4,313 Medicare Part D claims in 2023 as a Emergency Medicine Physician in GREEN BROOK, New Jersey, prescribing 89% generic.

4K
Part D claims, 2023
89%
generic prescribing
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.

JOHN CHAFOS, MD's Medicare Part D volume vs every U.S. prescriber

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

4,313 Top 8% higher than 92% 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%). Below this entry. 1,000–1,200: 31,827 prescribers (2%). Below this entry. 1,200–1,400: 26,224 prescribers (2%). Below this entry. 1,400–1,600: 21,710 prescribers (2%). Below this entry. 1,600–1,800: 19,072 prescribers (1%). Below this entry. 1,800–2,000: 16,451 prescribers (1%). Below this entry. 2,000–2,200: 213,991 prescribers (16%). This entry sits in this band. 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)

JOHN CHAFOS, MD 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 JOHN CHAFOS, MD?

Quality data not reported

NPI registry status

Active

Issued 10/16/2006

NPI 1871673830

Primary specialty

Emergency Medicine Physician

High-volume

64,398 US NPIs in this specialty

Medicare Part D claims

4,313 1125% vs specialty avg

2023 prescription claims

Specialty avg: 352

Specialty distribution in New Jersey

How Emergency Medicine Physician compares to other specialties among New Jersey providers

New Jersey providers

Emergency Medicine Physician share within New Jersey

1. Emergency Medicine Physician42%2. Internal medicine21%3. Family medicine17%4. Surgical12%5. Pediatric8%
Emergency Medicine Physician share within New Jersey

Specialty board-certification context

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

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

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

0%100%78%
Est. board-certified rate (Emergency Medicine 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).

JOHN CHAFOS, MD is a Emergency Medicine Physician provider practicing in GREEN BROOK, New Jersey, according to the CMS National Plan and Provider Enumeration System (NPPES). Credentials: MD. NPI: 1871673830. 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.

JOHN CHAFOS, MD appears in the CMS NPPES registry as a Emergency Medicine Physician provider holding MD credentials at 257 RT 22 EAST, GREEN BROOK, NJ, 08812, with a listed phone of (732) 968-8832. NPI 1871673830 was issued on 10/16/2006. Because NPPES data is self-reported by the provider and refreshed monthly, the address, phone, and specialty reflect what CHAFOS 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 4,313 prescription claims written by this provider, covering 560 Medicare beneficiaries and totaling roughly $457K in drug spend, split 11% brand-name and 89% generic by claim count, with an opioid prescribing rate of 1.0%. 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.

Emergency Medicine Physician is a high-volume specialty nationwide, with 64,398 enrolled providers across 56 states and an average of 352 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

257 RT 22 EAST
GREEN BROOK, NJ 08812

Provider Details

NPI 1871673830
Specialty Emergency Medicine Physician
Credentials MD
Gender Male
NPI Issued 10/16/2006

Hospital and facility affiliations

Facilities where JOHN CHAFOS, MD 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.

FAMILY CARE PA
HILLSBOROUGH, NJ

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

Brand vs generic prescribing mix · Typical

JOHN CHAFOS, MD — brand share 11.0%
Specialty average (est.)

11% brand-name claims vs 89% generic, on 4,313 2023 Medicare Part D claims.

The federal Medicare Part D Generic Dispensing Rate national benchmark sits near 90% generic / 10% brand for primary-care prescribers, per CMS Office of the Actuary 2024 estimates. Higher brand share is common in specialty prescribing where generic equivalents are not available.

Medicare Part D Prescribing Data

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

4,313
Total Claims
$457K
Total Drug Cost
560
Medicare Beneficiaries

Prescribing Breakdown

30-Day Fills
8,851
Total Day Supply
238,704
Brand vs Generic
11% brand / 89% generic
Brand Drug Cost
$368K
Generic Drug Cost
$87K
Opioid Claims
45 (1.0% rate)
Antibiotic Claims
567

Patient Demographics

Average Patient Age
74.2 years
Avg HCC Risk Score
1.11
Gender Split
58% female / 42% male
Age Distribution
<65: 28, 65-74: 275, 75-84: 195, 85+: 62

Top Prescribed Drugs (Medicare Part D)

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

Drug Claims
Dexamethasone
215
Prednisone
150
Atorvastatin Calcium
136
Rosuvastatin Calcium
125
Metformin Hcl
119
Metoprolol Succinate
119
Amlodipine Besylate
111
Cefdinir
108
Azithromycin
107
Amoxicillin-Clavulanate Potass
Amoxicillin/Potassium Clav
84

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

Emergency Medicine Physician Overview

How JOHN CHAFOS, MD fits within the Emergency Medicine Physician landscape nationally.

64,398
Emergency Medicine Physician Providers in US
56
States with Emergency Medicine Physician
352
Avg Claims per Provider

JOHN CHAFOS, MD's 4,313 claims are above the specialty average of 352.

Nearby Emergency Medicine Physician Providers in New Jersey

Other clinicians with the same primary specialty enrolled in New Jersey, drawn from the same CMS NPPES roster as CHAFOS.

Compare Emergency Medicine Physician nationally: see state-by-state distribution →

Frequently Asked Questions

What is JOHN CHAFOS, MD's specialty?
JOHN CHAFOS, MD specializes in Emergency Medicine Physician and practices in GREEN BROOK, New Jersey. Credentials: MD.
How much does JOHN CHAFOS, MD prescribe under Medicare Part D?
In 2023, JOHN CHAFOS, MD wrote 4,313 Medicare Part D claims totaling $457K in drug costs for 560 beneficiaries.
Where is JOHN CHAFOS, MD located?
JOHN CHAFOS, MD is located at 257 RT 22 EAST, GREEN BROOK, NJ, 08812. Phone: (732) 968-8832.
What is JOHN CHAFOS, MD's NPI number?
JOHN CHAFOS, MD's National Provider Identifier (NPI) is 1871673830, issued on 10/16/2006.
Does JOHN CHAFOS, MD prescribe more brand-name or generic drugs?
JOHN CHAFOS, MD's prescribing is 11% brand-name and 89% generic drugs by claim count, with $368K in brand drug costs.
Does JOHN CHAFOS, MD prescribe opioids?
Yes, JOHN CHAFOS, MD had 45 opioid claims in 2023 with an opioid prescribing rate of 1.0%.
How many Emergency Medicine Physician providers are there in the US?
There are 64,398 Emergency Medicine Physician providers across 56 states in the US. The average Emergency Medicine Physician provider writes 352 Medicare Part D claims per year.
What drugs does JOHN CHAFOS, MD prescribe most often?
Based on 2023 Medicare Part D data, JOHN CHAFOS, MD's most frequently prescribed drugs include Dexamethasone, Prednisone, Atorvastatin Calcium. This reflects Medicare Part D prescriptions only and does not include commercial insurance or other payer types.
Does JOHN CHAFOS, MD accept Medicare?
JOHN CHAFOS, MD appears in CMS Medicare data with 4,313 Part D claims and 560 Medicare beneficiaries in 2023. Contact the provider's office directly to confirm current Medicare enrollment and accepted plans.
How can I verify JOHN CHAFOS, MD's credentials?
JOHN CHAFOS, MD's NPI is 1871673830 with credentials MD. 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