WILLIS JOHN RIEKER JR. M.D.
NPI 1689714834
Pathology - Cytopathology in Beloit, WI

Q: What is Willis Rieker's NPI number?

The NPI number for Willis Rieker is 1689714834. It was assigned to this individual provider in the NPPES registry on February 7, 2007.

Q: What is Willis Rieker's specialty?

The primary specialty registered for this NPI is Pathology, specializing in Cytopathology, with taxonomy code 207ZC0500X.

Q: When was this NPI record last updated?

The NPPES record for Willis Rieker was last updated on September 11, 2025. NPI Profile syncs weekly with the NPPES registry data releases published by CMS. This NPI record was last updated 10 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.

Active since February 07, 2007PECOS EnrolledAccepts Medicare Assignment

1969 W HART RD, BELOIT, WI 53511(608) 364-5131(608) 364-3185 Get Directions Write a Review

NPPES record last updated: September 11, 2025. Verified against the NPPES registry weekly; last sync: August 02, 2026.

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About Willis John Rieker Jr. M.d. NPPES

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

WILLIS JOHN RIEKER JR. M.D. (NPI 1689714834) is an individual cytopathology provider in Beloit, Wisconsin, licensed in Wisconsin (35629-020) and active in the NPI registry since February 2007. He is enrolled in Medicare PECOS, is affiliated with Beloit Health System, and is a graduate of Loyola University Of Chicago, Stritch School Of Medicine (1984).

NPPES Registry Identity

NPI1689714834

Entity TypeIndividualMale

Primary Taxonomy207ZC0500X

Provider Legal NameWILLIS JOHN RIEKER JR.Credential: M.D.

Location Address1969 W HART RDBeloit, WI 53511-2230

Mailing Address1969 W Hart RdBeloit, WI 53511-2230 · (608) 364-5131 · Fax (608) 364-3185

Phone(608) 364-5131

Fax(608) 364-3185

Sole ProprietorYes

Medical School CMSLoyola University Of Chicago, Stritch School Of MedicineGraduated 1984

Enumeration DateFebruary 7, 2007

Last NPPES UpdateSeptember 11, 2025

✔ NPI 1689714834 is a valid, active identifier and passes the ISO check-digit test.

Specialties & Licenses 2

★ Primary SpecialtyPathology · CytopathologyAllopathic & Osteopathic Physicians

Taxonomy Code207ZC0500X

License✔ Licensed in WI · 35629-020

Definition

A cytopathologist is an anatomic pathologist trained in the diagnosis of human disease by means of the study of cells obtained from body secretions and fluids, by scraping, washing, or sponging the surface of a lesion, or by the aspiration of a tumor mass or body organ with a fine needle. A major aspect of a cytopathologist's practice is the interpretation of Papanicolaou-stained smears of cells from the female reproductive systems, the Pap test. However, the cytopathologist's expertise is applied to the diagnosis of cells from all systems and areas of the body. He/she is a consultant to all medical specialists.

Also ListedPathology · Anatomic Pathology & Clinical PathologyTaxonomy 207ZP0102X · License 35629-020 (WI)

1969 W HART RD, Beloit, WI 53511

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Other Identifiers 1

Medicaid32846400WI

Medicare Participation & PECOS CMS

Medicare enrollment, assignment, and ordering and referring status from the CMS PECOS system.

Medicare Enrollment Status

✔

Enrolled in Medicare and accepts Medicare assignment

Willis John Rieker Jr. 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 ID7012976012

PECOS Enrollment IDI20111227000167

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.

Areas of Expertise CMS Part B claims 17

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.

Pathology examination of tissue using a microscope, intermediate complexity 88305

A pathology examination of tissue with intermediate complexity involves studying a small sample of your body tissue under a microscope. This helps in identifying any abnormal cells or signs of disease. It's a detailed process requiring expert analysis to ensure accurate results.

997 services269 patients

Special stained specimen slides to examine tissue including interpretation and report 88313

Special stained specimen slides are used to examine tissue samples. This involves applying special dyes to the tissue, which helps to highlight certain features under a microscope. The findings are then interpreted and a report is provided. This can aid in diagnosing various health conditions.

394 services118 patients

Pathology examination of tissue using a microscope, intermediate complexity 88305

232 services173 patients

Special stained specimen slides to identify organisms including interpretation and report 88312

This service involves coloring specimen slides in a special way to help identify organisms. The colors make different parts of the organism stand out. Afterward, a detailed interpretation and report on the findings are provided.

199 services115 patients

Special stained specimen slides to examine tissue, each additional procedure 88341

Special stained specimen slides are used to analyze tissue in detail. In this process, extra procedures may be needed for a more thorough examination. These involve applying special stains to the tissue on slides, enhancing specific elements for closer study.

81 services12 patients

Cell examination of specimen, concentration technique 88108

Cell examination of a specimen using a concentration technique is a lab process that enhances the detection of cells in a sample. This method helps to focus on key areas of the sample, making it easier to spot abnormalities or changes. It's a crucial part of diagnosing and monitoring certain health conditions.

80 services67 patients

Special stained specimen slides to examine tissue, each multiplex procedure 88344

Special stained specimen slides are used to study tissue in detail. This multiplex procedure involves applying different dyes to the tissue sample on a slide to highlight specific elements. These colors help identify any abnormalities in the tissue, aiding in accurate diagnosis and treatment planning.

80 services15 patients

Special stained specimen slides to examine tissue, initial procedure 88342

This procedure involves the use of specially stained slides to examine tissue samples. The initial process involves obtaining a small tissue sample from your body. This sample is then placed on a slide and stained with special dyes to highlight different structures and elements. The stained slide is then examined under a microscope to help diagnose any potential health issues.

72 services20 patients

Pathology examination of specimen during surgery, first tissue block 88331

A pathology examination during surgery involves the immediate analysis of a removed tissue sample. This helps the surgeon make decisions during your operation. The "first tissue block" refers to the initial sample examined. It's a vital step to ensure your health.

70 services51 patients

Pathology examination of tissue using a microscope, limited examination 88300

A pathology examination of tissue using a microscope is a procedure where a small sample of your tissue is observed under a microscope. This limited examination helps identify any abnormal cells or signs of disease, aiding in accurate diagnosis and treatment planning.

54 services25 patients

Cell examination of specimen, concentration technique 88108

39 services29 patients

Pathology examination of tissue using a microscope, moderately high complexity 88307

A pathology examination of tissue with moderate complexity involves a detailed study of a small tissue sample from your body. Using a microscope, experts analyze the tissue's structure and cells to identify any abnormalities. This helps in diagnosing various health conditions accurately.

29 services22 patients

Pathology examination of tissue using a microscope, moderately low complexity 88304

A pathology examination of tissue, moderately low complexity, involves studying a small sample of your body tissue under a microscope. It helps to identify any abnormal cells or diseases. It's a routine procedure, not complex, and provides crucial insights for your diagnosis.

28 services27 patients

Evaluation of fine needle aspirate with interpretation and report 88173

This procedure involves using a thin needle to collect a small sample from an abnormal area or lump. The sample is then examined under a microscope to identify any potential issues. A report of the findings is provided for further analysis.

26 services11 patients

Pathology examination of tissue using a microscope, limited examination 88300

16 services13 patients

Surgical pathology, gross and microscopic examinations, for prostate needle biopsy, any method G0416

This procedure involves taking a small tissue sample from your gland located beneath your bladder. The sample is then examined under a microscope by a pathologist to check for any abnormalities or diseases. This is a standard method to ensure your well-being.

16 services16 patients

Preparation of tissue for examination by removing any calcium present 88311

This procedure involves treating tissue samples to remove any calcium, which can interfere with the examination. The tissue is soaked in a special solution that safely dissolves the calcium, leaving the tissue intact for accurate analysis. This helps in making precise diagnoses.

13 services11 patients

Hospital Affiliations CMS Care Compare

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

Beloit Health System

Acute Care Hospitals · Beloit, WI

4/5 CMS rating

OwnershipVoluntary non-profit - Private

CMS Certification Number520100

Location1969 W Hart RdBeloit, WI 53511 · Rock County

Emergency services Birthing friendly

Physician Visit Costs CMS claims · ZIP area

Typical Medicare office-visit costs in the 53511 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

$123.69 typical visit price

range $53.90 – $163.24

Typical copayment $30.92 (range $13.47 – $40.81)

Most-billed visit code 99204

Established Patient

$95.41 typical visit price

range $17.40 – $133.76

Typical copayment $23.85 (range $4.35 – $33.44)

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.

Other Providers at the Same Location NPPES 20

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

DR. USMAN SARWAR M.D.

Internal Medicine (Cardiovascular Disease)

1969 W HART RD
BELOIT, WI 53511

Rock County (608) 364-5011

JESSICA M. FRANTZ CCC/SLP

Speech-Language Pathologist

1969 W HART RD, BELOIT HEALTH SYSTEM INC/ BELOIT MEMORIAL HOSPITAL
BELOIT, WI 53511

Rock County (608) 364-5695

MRS. CAROL J KATROSCIK MSW LCSW

Social Worker (Clinical)

1969 W HART RD
BELOIT, WI 53511

Rock County (608) 364-5686

MRS. SALLY J GREER MS LPC

Counselor (Professional)

1969 W HART RD
BELOIT, WI 53511

Rock County (608) 364-5686

YEHIA A. KHOGA MD

Psychiatry & Neurology (Child & Adolescent Psychiatry)

1969 W HART RD
BELOIT, WI 53511

Rock County (608) 364-5686

MIGUEL A JIMENEZ MD

Radiology (Diagnostic Radiology)

1969 W HART RD
BELOIT, WI 53511

Rock County (608) 364-5269

STACY HEITZ PA-C

Physician Assistant

1969 W HART RD
BELOIT, WI 53511

Rock County (608) 364-5011

STEVEN STEPHEN CHOUNG MD

Anesthesiology

1969 W HART RD, BELOIT MEMORIAL HOSPITAL
BELOIT, WI 53511

Rock County (608) 362-7444

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 Willis Rieker's NPI number?

The NPI number for Willis Rieker is 1689714834. It was assigned to this individual provider in the NPPES registry on February 7, 2007.

Where is Willis Rieker located?

Willis Rieker practices at 1969 W Hart Rd, Beloit, WI 53511. The listed phone number is (608) 364-5131.

What is Willis Rieker's specialty?

The primary specialty registered for this NPI is Pathology, specializing in Cytopathology, with taxonomy code 207ZC0500X.

Is Willis Rieker enrolled in Medicare?

Yes. Willis Rieker 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.

Is Willis Rieker affiliated with any hospitals?

According to CMS data, Willis Rieker is affiliated with Beloit Health System.

When was this NPI record last updated?

The NPPES record for Willis Rieker was last updated on September 11, 2025. NPI Profile syncs weekly with the NPPES registry data releases published by CMS. This NPI record was last updated 10 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.