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DR. WILLIAM STUART ASCH M.D., PH.D.
NPI 1003933326
Internal Medicine - Nephrology in New Haven, CT

Active since March 23, 2007PECOS EnrolledAccepts Medicare Assignment
73.56/100
CMS Quality Rating
20 YORK STREET CB 2041, HOSPITALIST SERVICE, NEW HAVEN, CT 06510(203) 688-4748(203) 688-4740 Get Directions Write a Review

NPPES record last updated: October 27, 2007. Verified against the NPPES registry weekly; last sync: October 18, 2026.

About Dr. William Stuart Asch M.d., Ph.d. NPPES

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

DR. WILLIAM STUART ASCH M.D., PH.D. (NPI 1003933326) is an individual nephrology provider in New Haven, Connecticut, licensed in Connecticut (044496) and active in the NPI registry since March 2007. He is enrolled in Medicare PECOS and is a graduate of State University Of New York At Stony Brook, School Of Medicine (2001).

NPPES Registry Identity

NPI1003933326
Entity TypeIndividualMale
Primary Taxonomy207RN0300X
Provider Legal NameDR. WILLIAM STUART ASCHCredential: M.D., PH.D.
Location Address20 YORK STREET CB 2041, HOSPITALIST SERVICENew Haven, CT 06510
Mailing Address216 Bishop Street, Apartment 314New Haven, CT 06511-3794 · (203) 785-4184 · Fax (203) 785-7068
Phone(203) 688-4748
Fax(203) 688-4740
Sole ProprietorNo
Medical School CMSState University Of New York At Stony Brook, School Of MedicineGraduated 2001
Enumeration DateMarch 23, 2007
Last NPPES UpdateOctober 27, 2007
✔ NPI 1003933326 is a valid, active identifier and passes the ISO check-digit test.

Specialties & Licenses 3

★ Primary SpecialtyInternal Medicine · NephrologyAllopathic & Osteopathic Physicians
Taxonomy Code207RN0300X
License✔ Licensed in CT · 044496
Definition
An internist who treats disorders of the kidney, high blood pressure, fluid and mineral balance and dialysis of body wastes when the kidneys do not function. This specialist consults with surgeons about kidney transplantation.
Also ListedInternal MedicineTaxonomy 207R00000X · License 044496 (CT)
Also ListedHospitalistTaxonomy 208M00000X · License 044496 (CT)
20 YORK STREET CB 2041, New Haven, CT 06510
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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. William Stuart Asch M.d., Ph.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 ID4082772140
PECOS Enrollment IDI20081020000215
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 William Asch reassigns Medicare billing to 2 organizations. Each organization bills Medicare for the services this provider delivers there; the nearest is listed first.

Yale University
0.4 mi
Advanced Practice Midwife
100 CHURCH ST S STE 200, YALE SCHOOL OF NURSING
New Haven, CT 06519
  • Reassigned Medicare billing, Connecticut enrollment
  • 3,728 clinicians in this Medicare group
NPI 1124148887 (203) 737-5432
Greenwich Hospital
41 mi
General Acute Care Hospital
5 PERRYRIDGE RD
Greenwich, CT 06830
  • Reassigned Medicare billing, Connecticut enrollment
  • 268 clinicians in this Medicare group
NPI 1609846088 (203) 863-3000

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 7

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.
257 services79 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.
119 services89 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.
70 services52 patients
Initial hospital care with straightforward or low-level medical decision making, if using time, at least 55 minutes 99222
Initial hospital inpatient care is a service where a healthcare provider spends about 50 minutes per day overseeing your care while you're admitted in the hospital. This includes reviewing your health status, planning your treatment, and ensuring your safety and comfort.
47 services46 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.
25 services14 patients
Needle biopsy of kidney 50200
A needle biopsy of the kidney is a medical procedure where a small sample of kidney tissue is removed using a special needle. This is done to examine the tissue under a microscope for any abnormalities. It helps in diagnosing potential kidney conditions.
21 services18 patients

Physician Visit Costs CMS claims · ZIP area

Typical Medicare office-visit costs in the 06510 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
$138.84 typical visit price
range $60.82 – $183.10
Typical copayment $34.71 (range $15.20 – $45.77)
Most-billed visit code 99204
Established Patient
$106.68 typical visit price
range $19.76 – $149.26
Typical copayment $26.67 (range $4.94 – $37.31)
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.

73.56/100
MIPS Final ScoreMerit-based Incentive Payment System · CMS Quality Payment Program
Scored as part of a group practice
Quality75.84
Promoting Interoperability74
Improvement Activities40
Cost51.43

Referred Medical Equipment & Supplies CMS DME claims 12

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

Azathioprine, oral, 50 mg J7500
Treatment-Treatment - Miscellaneous · category RX029N
4 suppliers62 claims2,793 services$4.34 avg. paid by Medicare
Cyclosporine, oral, 100 mg J7502
Treatment-Treatment - Miscellaneous · category RX029N
2 suppliers27 claims1,560 services$1.55 avg. paid by Medicare
Tacrolimus, extended release, (envarsus xr), oral, 0.25 mg J7503
Treatment-Chemotherapy · category RH002N
8 suppliers310 claims103,693 services$1.21 avg. paid by Medicare
Tacrolimus, immediate release, oral, 1 mg J7507
Treatment-Treatment - Miscellaneous · category RX029N
21 suppliers287 claims39,586 services$0.31 avg. paid by Medicare
Prednisone, immediate release or delayed release, oral, 1 mg J7512
Treatment-Treatment - Miscellaneous · category RX029N
16 suppliers282 claims46,250 services$0.01 avg. paid by Medicare
Cyclosporine, oral, 25 mg J7515
Treatment-Treatment - Miscellaneous · category RX029N
3 suppliers30 claims4,530 services$0.54 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

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

CINDY IRENE BOUTILIER APRN
Nurse Practitioner
20 YORK STREET CB 2041, NORTHEAST MEDICAL GROUP
NEW HAVEN, CT 06510
South Central Connecticut Planning Region (203) 688-4748

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 William Asch's NPI number?

The NPI number for William Asch is 1003933326. It was assigned to this individual provider in the NPPES registry on March 23, 2007.

Where is William Asch located?

William Asch practices at 20 York Street Cb 2041 Hospitalist Service, New Haven, CT 06510. The listed phone number is (203) 688-4748.

What is William Asch's specialty?

The primary specialty registered for this NPI is Internal Medicine, specializing in Nephrology, with taxonomy code 207RN0300X.

Is William Asch enrolled in Medicare?

Yes. William Asch 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 William Asch's services?

According to the CMS Revalidation Reassignment List (October 2026 release), William Asch reassigns Medicare benefits to 2 organizations: Yale University (New Haven, CT) and Greenwich Hospital (Greenwich, CT). 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 William Asch'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 William Asch was last updated on October 27, 2007. NPI Profile syncs weekly with the NPPES registry data releases published by CMS. This NPI record was last updated 18 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.