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DR. GERARD JOHN DIEFES M.D.
NPI 1417948951
Internal Medicine - Pulmonary Disease in Wynnewood, PA

Active since November 03, 2005PECOS EnrolledAccepts Medicare Assignment
100/100
CMS Quality Rating
1001 CITY LINE AVE, WB 113, WYNNEWOOD, PA 19096(610) 896-0280(610) 896-0286 Get Directions Write a Review

NPPES record last updated: May 20, 2025. Verified against the NPPES registry weekly; last sync: October 18, 2026.

About Dr. Gerard John Diefes M.d. NPPES

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

DR. GERARD JOHN DIEFES M.D. (NPI 1417948951) is an individual pulmonary disease provider in Wynnewood, Pennsylvania, licensed in Pennsylvania (MD056949L) and active in the NPI registry since November 2005. He is enrolled in Medicare PECOS, is affiliated with Hospital Of Univ Of Pennsylvania, and maintains a secondary practice location in Exton.

NPPES Registry Identity

NPI1417948951
Entity TypeIndividualMale
Primary Taxonomy207RP1001X
Provider Legal NameDR. GERARD JOHN DIEFESCredential: M.D.
Location Address1001 CITY LINE AVE, WB 113Wynnewood, PA 19096-3902
Mailing Address1001 City Line Ave, Wb 113Wynnewood, PA 19096-3902 · (610) 896-0280 · Fax (610) 896-0286
Phone(610) 896-0280
Fax(610) 896-0286
Sole ProprietorNo
Medical School CMSHahnemann University College Of MedicineGraduated 1992
Enumeration DateNovember 3, 2005
Last NPPES UpdateMay 20, 2025
NPPES CertifiedMay 20, 2025
✔ NPI 1417948951 is a valid, active identifier and passes the ISO check-digit test.

Specialties & Licenses 3

★ Primary SpecialtyInternal Medicine · Pulmonary DiseaseAllopathic & Osteopathic Physicians
Taxonomy Code207RP1001X
License✔ Licensed in PA · MD056949L
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 ListedInternal Medicine · Critical Care MedicineTaxonomy 207RC0200X · License MD056949L (PA)
Also ListedInternal Medicine · Sleep MedicineTaxonomy 207RS0012X · License MD056949L (PA)
1001 CITY LINE AVE, Wynnewood, PA 19096
Open in Google Maps ↗

Secondary Practice Location 1

Location 1736 W Lincoln HwyExton, PA 19341-2547 · Phone (610) 359-5858

Other Identifiers 1

Medicaid001781333PA

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

Dr. Gerard John Diefes M.d. 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 ID8729044094
PECOS Enrollment IDI20050613000167
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

2

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

Respiratory Associates, Ltd
1.3 mi
Specialist
1001 CITY AVE, WB 113
Wynnewood, PA 19096
  • Reassigned Medicare billing, Pennsylvania enrollment
  • 3 clinicians in this Medicare group
NPI 1073534939 (610) 896-0280
Advocare, LLC
20 mi
Pediatrics
401 ROUTE 73 N STE 320
Marlton, NJ 08053
  • Reassigned Medicare billing, Pennsylvania enrollment
  • 135 clinicians in this Medicare group
NPI 1770538696 (856) 872-7055

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 11

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 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.
822 services156 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.
212 services64 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.
175 services86 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.
142 services86 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.
68 services60 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.
63 services58 patients

Hospital Affiliations CMS Care Compare 5

Hospitals where this provider delivers care, identified from recent Medicare claims and place-of-service records.

Hospital Of Univ Of Pennsylvania

Acute Care Hospitals · Philadelphia, PA
5/5 CMS rating
OwnershipVoluntary non-profit - Private
CMS Certification Number390111
Location34th & Spruce StsPhiladelphia, PA 19104 · Philadelphia County
Emergency services Birthing friendly

Paoli Hospital

Acute Care Hospitals · Paoli, PA
5/5 CMS rating
OwnershipVoluntary non-profit - Private
CMS Certification Number390153
Location255 West Lancaster AvenuePaoli, PA 19301 · Chester County
Emergency services Birthing friendly

Chester County Hospital

Acute Care Hospitals · West Chester, PA
5/5 CMS rating
OwnershipVoluntary non-profit - Private
CMS Certification Number390179
Location701 East Marshall StreetWest Chester, PA 19380 · Chester County
Emergency services Birthing friendly

Main Line Hospital Lankenau

Acute Care Hospitals · Wynnewood, PA
4/5 CMS rating
OwnershipVoluntary non-profit - Private
CMS Certification Number390195
Location100 Lancaster AveWynnewood, PA 19096 · Montgomery County
Emergency services Birthing friendly

St Mary Medical Center

Acute Care Hospitals · Langhorne, PA
2/5 CMS rating
OwnershipVoluntary non-profit - Private
CMS Certification Number390258
LocationLanghorne-Newtown RdLanghorne, PA 19047 · Bucks County
Emergency services

Physician Visit Costs CMS claims · ZIP area

Typical Medicare office-visit costs in the 19096 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
$137.17 typical visit price
range $59.88 – $180.99
Typical copayment $34.29 (range $14.97 – $45.24)
Most-billed visit code 99204
Established Patient
$105.21 typical visit price
range $19.30 – $147.29
Typical copayment $26.30 (range $4.82 – $36.82)
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.

Medicare Quality Performance CMS QPP · MIPS

Performance in the CMS Quality Payment Program: the MIPS final score across four weighted categories, and the individual quality measures reported to Medicare.

100/100
MIPS Final ScoreMerit-based Incentive Payment System · CMS Quality Payment Program
Individually scored
Quality100
Improvement Activities40
Cost73.54

Reported Quality Measures

Advance Care Plan
100%217 patients5/55-star benchmark: 100%
Chronic Obstructive Pulmonary Disease (COPD): Long-Acting Inhaled Bronchodilator Therapy
100%23 patients
Controlling High Blood Pressure
92%26 patients5/55-star benchmark: 91%
Documentation of Current Medications in the Medical Record
100%690 patients5/55-star benchmark: 100%
Preventive Care and Screening: Body Mass Index (BMI) Screening and Follow-Up Plan
100%407 patients5/55-star benchmark: 100%
Preventive Care and Screening: Tobacco Use: Screening and Cessation Intervention
Patients combinedPopulations: 100% · 220 patients
Patients screened: 100% · 220 patients
100%29 patients5/55-star benchmark: 100%
Sleep Apnea: Assessment of Adherence to Positive Airway Pressure Therapy
100%80 patients
Providers report different measures because they deliver different services; reporting more or less information is not a reflection of quality. Star ratings appear only where CMS assigned them.

Referred Medical Equipment & Supplies CMS DME claims 19

Durable medical equipment, devices and supplies this provider ordered from DME suppliers for patients, from Medicare fee-for-service claims.

Tubing with integrated heating element for use with positive airway pressure device A4604
DME-Other DME · category DE001N
5 suppliers38 claims38 services$31.69 avg. paid by Medicare
Full face mask used with positive airway pressure device, each A7030
DME-Other DME · category DE001N
3 suppliers20 claims20 services$70.95 avg. paid by Medicare
Face mask interface, replacement for full face mask, each A7031
DME-Other DME · category DE001N
3 suppliers19 claims51 services$26.17 avg. paid by Medicare
Cushion for use on nasal mask interface, replacement only, each A7032
DME-Other DME · category DE001N
4 suppliers23 claims129 services$15.50 avg. paid by Medicare
Pillow for use on nasal cannula type interface, replacement only, pair A7033
DME-Other DME · category DE001N
2 suppliers13 claims78 services$13.14 avg. paid by Medicare
Nasal interface (mask or cannula type) used with positive airway pressure device, with or without head strap A7034
DME-Other DME · category DE001N
5 suppliers42 claims42 services$44.55 avg. paid by Medicare
Dollar amounts are the average Medicare paid the supplier per service. They are not the cost to the patient.

Other Providers at the Same Location NPPES 2

Providers registered at the same practice address, or within the immediate area, according to the NPPES registry.

DR. GREGORY STEVEN LENCHNER M.D.
Internal Medicine (Pulmonary Disease)
1001 CITY LINE AVE, WB113
WYNNEWOOD, PA 19096
Montgomery County (610) 896-0280
DR. ROBERT ALAN PROMISLOFF D.O.
Internal Medicine (Pulmonary Disease)
1001 CITY LINE AVE, WB 113
WYNNEWOOD, PA 19096
Montgomery County (610) 896-0280

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 Gerard Diefes's NPI number?

The NPI number for Gerard Diefes is 1417948951. It was assigned to this individual provider in the NPPES registry on November 3, 2005.

Where is Gerard Diefes located?

Gerard Diefes practices at 1001 City Line Ave Wb 113, Wynnewood, PA 19096. The listed phone number is (610) 896-0280.

What is Gerard Diefes's specialty?

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

Is Gerard Diefes enrolled in Medicare?

Yes. Gerard Diefes 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 Gerard Diefes's services?

According to the CMS Revalidation Reassignment List (October 2026 release), Gerard Diefes reassigns Medicare benefits to 2 organizations: Respiratory Associates, Ltd (Wynnewood, PA) and Advocare, LLC (Marlton, NJ). 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 Gerard Diefes's services. Reassignment records can lag staffing changes; confirm current arrangements with the organization.

Is Gerard Diefes affiliated with any hospitals?

According to CMS data, Gerard Diefes is affiliated with Hospital Of Univ Of Pennsylvania, Paoli Hospital, Chester County Hospital, Main Line Hospital Lankenau and St Mary Medical Center.

When was this NPI record last updated?

The NPPES record for Gerard Diefes was last updated on May 20, 2025. NPI Profile syncs weekly with the NPPES registry data releases published by CMS. This NPI record was last updated 17 months 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.