DR. WILLIAM EDWARD RIETKERK MD MBA
NPI 1720311400
Dermatology in Thousand Oaks, CA

Q: What is William Rietkerk's NPI number?

The NPI number for William Rietkerk is 1720311400. It was assigned to this individual provider in the NPPES registry on September 11, 2009.

Q: What is William Rietkerk's specialty?

The primary specialty registered for this NPI is Dermatology with taxonomy code 207N00000X.

Q: When was this NPI record last updated?

The NPPES record for William Rietkerk was last updated on July 21, 2022. NPI Profile syncs weekly with the NPPES registry data releases published by CMS. This NPI record was last updated 4 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.

Active since September 11, 2009PECOS EnrolledAccepts Medicare Assignment

77.86/100

CMS Quality Rating

55 ROLLING OAKS DR STE 200, THOUSAND OAKS, CA 91361(212) 661-3376(212) 661-3366 Get Directions Write a Review

NPPES record last updated: July 21, 2022. Verified against the NPPES registry weekly; last sync: October 18, 2026.

Record update history: Jul 21, 2022, Jul 31, 2017 (2 updates tracked since 2017).

On this page

About Dr. William Edward Rietkerk Md Mba NPPES

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

DR. WILLIAM EDWARD RIETKERK MD MBA (NPI 1720311400) is an individual dermatology provider in Thousand Oaks, California, licensed in California (A141249) and active in the NPI registry since September 2009. He is enrolled in Medicare PECOS and is a graduate of University Of California, Irvine, California College Of Medicine (2008).

NPPES Registry Identity

NPI1720311400

Entity TypeIndividualMale

Primary Taxonomy207N00000X

Provider Legal NameDR. WILLIAM EDWARD RIETKERKCredential: MD MBA

Location Address55 ROLLING OAKS DR STE 200Thousand Oaks, CA 91361-1010

Mailing Address55 Rolling Oaks Drive, Suite 200Thousand Oaks, CA 91361 · (805) 497-7529 · Fax (805) 494-3486

Phone(212) 661-3376

Fax(212) 661-3366

Sole ProprietorNo

Medical School CMSUniversity Of California, Irvine, California College Of MedicineGraduated 2008

Enumeration DateSeptember 11, 2009

Last NPPES UpdateJuly 21, 20222 updates tracked since enumeration

✔ NPI 1720311400 is a valid, active identifier and passes the ISO check-digit test.

Specialties & Licenses

★ Primary SpecialtyDermatologyAllopathic & Osteopathic Physicians

Taxonomy Code207N00000X

License✔ Licensed in CA · A141249

Definition

A dermatologist is trained to diagnose and treat pediatric and adult patients with benign and malignant disorders of the skin, mouth, external genitalia, hair and nails, as well as a number of sexually transmitted diseases. The dermatologist has had additional training and experience in the diagnosis and treatment of skin cancers, melanomas, moles and other tumors of the skin, the management of contact dermatitis and other allergic and nonallergic skin disorders, and in the recognition of the skin manifestations of systemic (including internal malignancy) and infectious diseases. Dermatologists have special training in dermatopathology and in the surgical techniques used in dermatology. They also have expertise in the management of cosmetic disorders of the skin such as hair loss and scars and the skin changes associated with aging.

55 ROLLING OAKS DR STE 200, Thousand Oaks, CA 91361

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Accepted Insurance

The full list of accepted plans is on the Insurance tab. Issuers include UnitedHealthcare.Insurance ›

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 Edward Rietkerk Md Mba 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 ID5991968497

PECOS Enrollment IDI20160819001642

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 Reassignment

Medicare enrollment records show William Rietkerk reassigns Medicare billing to 1 organization. The organization bills Medicare for the services this provider delivers there.

J Robert West, M.D., Inc

69 mi

Dermatology

400 NEWPORT CENTER DR STE 702
Newport Beach, CA 92660

Reassigned Medicare billing, California enrollment
Medicare enrollment name: J Robert West MD Inc
121 clinicians in this Medicare group

NPI 1932154788 (949) 644-0101

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 31

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.

Destruction of precancer skin growth, 2-14 growths 17003

This procedure involves removing 2-14 precancerous skin growths. The growths are treated to prevent them from potentially developing into skin cancer. The process is safe, with minimal discomfort, and promotes healthier skin.

5,448 services687 patients

Established patient office or other outpatient visit with low level od decision making, if using time, 20 minutes or more 99213

This is a routine visit for patients who have already been seen by the healthcare provider. During this approximately 20-29 minute appointment, your health status will be evaluated and any necessary treatments or tests will be discussed. It's a chance to address any health concerns you may have.

2,775 services1,237 patients

Destruction of precancer skin growth, 1 growth 17000

"Destruction of precancer skin growth" is a procedure that eliminates a single precancerous skin growth. This is done to prevent it from developing into skin cancer. The growth may be removed using various methods such as cryotherapy (freezing), laser therapy, or topical medications.

1,482 services843 patients

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.

1,384 services741 patients

Destruction of skin growth, 1-14 growths 17110

"Destruction of skin growth" refers to a procedure where 1-14 abnormal skin growths are removed. This is done using methods such as freezing, burning, or laser therapy. It helps prevent the growth from causing discomfort or turning into a more serious condition.

1,131 services778 patients

Superficial and/or low voltage radiation treatment delivery 77401

Superficial and/or low voltage radiation treatment delivery is a non-invasive procedure used to treat certain diseases like skin cancer. It uses low energy radiation to target and destroy abnormal cells, aiding in halting disease progression.

718 services63 patients

Biopsy of related skin growth, first growth 11102

A biopsy of a skin growth involves taking a small sample of the growth to examine it under a microscope. This helps determine if the growth is harmful. The procedure is typically quick, with minimal discomfort. It's a crucial step in ensuring your skin's health.

620 services516 patients

Established patient office or other outpatient visit with straightforward medical decision making, if using time, 10 minutes or more 99212

This is a routine check-up for patients who have previously seen the doctor. During this 10-19 minute visit, the doctor will review your health status, discuss any concerns, and manage ongoing treatments or medications. It's a chance to ensure your health is on track.

271 services219 patients

Biopsy of related skin growth, each additional growth 11103

A biopsy of related skin growth is a procedure where a small piece of skin growth is removed for testing. If additional growths are identified, they may also be biopsied. This helps in diagnosing skin conditions and planning appropriate treatment.

248 services166 patients

New patient office or other outpatient visit with low level of medical decision making, if using time, 30 minutes or more 99203

This service involves an initial office or outpatient visit for a new patient. The healthcare professional will spend 30-44 minutes understanding your health history, current issues, and discussing possible treatment plans. It's a comprehensive evaluation to start your healthcare journey.

175 services175 patients

Destruction of precancer skin growth, 15 or more growths 17004

This procedure involves removing 15 or more precancerous skin growths to prevent them from developing into cancer. It's done using various methods like freezing, creams, or minor surgery. The goal is to protect your health by stopping cancer before it starts.

137 services98 patients

Obtaining data needed to develop the optimal radiation treatment, 1 treatment area 77280

This procedure involves gathering essential information to create the best radiation treatment plan for a specific area. It includes scanning the treatment area and using this data to calculate the precise dose of radiation needed to target the disease effectively, while sparing healthy tissue.

110 services42 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.

98 services79 patients

Obtaining data needed to develop the optimal radiation treatment, 3 or more treatment areas or any number of treatment areas where special treatment is involved 77290

This procedure involves collecting necessary data to plan the best radiation treatment. It may cover 3 or more areas or any area requiring special attention. Data collection includes imaging scans and tests to understand the disease's extent and to tailor a precise, effective treatment plan.

87 services56 patients

Intermediate repair of wound of scalp, underarms, trunk, arms, or legs, 2.6-7.5 cm 12032

This procedure involves the repair of a wound between 2.6-7.5 cm located on the scalp, underarms, trunk, arms, or legs. The process includes cleaning, debridement (removal of damaged tissue), and suturing (stitching) of the wound to promote healing.

81 services75 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.

78 services67 patients

Calculation of radiation therapy dose 77300

Radiation therapy dose calculation is a process to determine the exact amount of radiation needed to treat a specific area in the body. This calculation helps ensure the treatment is effective while minimizing harm to healthy tissues. It's a key part of planning your radiation therapy.

66 services44 patients

Injection, triamcinolone acetonide, not otherwise specified, 10 mg J3301

Triamcinolone acetonide is a medication used to reduce inflammation in the body. It's given as a 10 mg injection for conditions like allergies, arthritis, or skin problems. The injection helps to decrease swelling, redness, and itching.

65 services27 patients

Destruction of skin growth, 15 or more growths 17111

"Destruction of skin growth" refers to a procedure where unwanted skin growths, such as warts or moles, are removed. In this case, 15 or more growths are treated. Techniques may include freezing, burning, or laser therapy. It's a safe, quick process to improve skin health.

54 services43 patients

Aminolevulinic acid hcl for topical administration, 20%, single unit dosage form (354 mg) J7308

Aminolevulinic Acid HCL is a medication applied to the skin to treat certain types of skin conditions. It works by making the skin more sensitive to light, which helps to kill abnormal skin cells. The 20% solution is a single dose of 354 mg.

52 services39 patients

Removal of cancer skin growth of body, arms, or legs, 1.1-2.0 cm 11602

This procedure involves the surgical removal of a cancerous skin growth on the body, arms, or legs. The growth is between 1.1 and 2.0 cm in size. The goal is to eliminate cancer cells and prevent them from spreading to other parts of the body.

51 services46 patients

Application of light to destroy precancer skin growth 96567

This procedure involves the use of special light to eradicate precancerous skin growths. The light targets abnormal cells causing them to die off, while leaving healthy skin unharmed. It's a non-invasive method that helps prevent skin cancer.

44 services34 patients

Punch biopsy, first skin growth 11104

A punch biopsy is a procedure where a small, circular tool is used to remove a sample of skin tissue. This is usually done to test a skin growth for potential issues. You may feel a pinch, but discomfort is minimal. The area heals quickly.

43 services43 patients

Injection into skin growth, 1-7 growths 11900

This procedure involves injecting medication into 1-7 skin growths. The medication helps to reduce the size of the growths or completely eliminate them. It's a simple, quick, and usually painless process performed by a medical professional.

40 services24 patients

Biopsy of ear 69100

A biopsy of the ear is a medical procedure where a small sample of tissue is taken from your ear for examination. This helps doctors diagnose any abnormalities or diseases. It's a simple process, usually done under local anesthesia, and has minimal risks.

39 services33 patients

Destruction of cancer skin growth of trunk, arms, or legs, 1.1-2.0 cm 17262

This procedure involves removing a cancerous skin growth on the trunk, arms, or legs that is between 1.1 and 2.0 cm in size. The growth is destroyed using methods like surgery, laser, or freezing, aiming to eliminate cancer and prevent its spread.

26 services19 patients

Removal of cancer skin growth of body, arms, or legs, 2.1-3.0 cm 11603

This procedure involves the removal of a cancerous skin growth, between 2.1 and 3.0 cm, from the body, arms, or legs. The area is numbed, then the growth is carefully cut out. The goal is to eliminate all cancer cells while minimizing scarring.

20 services20 patients

Complex radiation therapy planning 77263

Complex radiation therapy planning is a process to determine the most effective way to deliver radiation to a specific area in your body. It involves detailed imaging to map your body's structure, allowing for precise targeting of cancer cells while sparing healthy tissue.

18 services17 patients

New patient office or other outpatient visit with straightforward medical decision making, if using time, 15 minutes or more 99202

This service involves an initial visit to the doctor's office or other outpatient setting. It typically lasts between 15-29 minutes. The doctor will review your medical history, conduct a physical examination, and discuss your health concerns. It's a chance to establish your health baseline and address any immediate medical issues.

17 services17 patients

New patient office or other outpatient visit with moderate level of medical decision making, if using time, 45 minutes or more 99204

This is a first-time office or outpatient visit lasting between 45-59 minutes. The healthcare provider evaluates your health, discusses your medical history, and may suggest further tests or treatments. It's an opportunity to ask questions and understand your health better.

17 services17 patients

Destruction of cancer skin growth of trunk, arms, or legs, 0.6-1.0 cm 17261

This procedure involves the removal of a cancerous skin growth on the trunk, arms, or legs that is between 0.6 and 1.0 cm in size. The goal is to eliminate the cancerous cells and prevent further spread. The method of destruction may vary, including methods such as surgery, laser, or cryotherapy.

16 services14 patients

Physician Visit Costs CMS claims · ZIP area

Typical Medicare office-visit costs in the 91361 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

$95.28 typical visit price

range $62.32 – $185.36

Typical copayment $23.82 (range $15.58 – $46.34)

Most-billed visit code 99203

Established Patient

$77.11 typical visit price

range $20.68 – $151.85

Typical copayment $19.27 (range $5.17 – $37.96)

Most-billed visit code 99213

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.

77.86/100

MIPS Final ScoreMerit-based Incentive Payment System · CMS Quality Payment Program

Scored as part of a group practice

Quality

58.05

Promoting Interoperability

Improvement Activities

Cost

73.99

Reported Quality Measures

Advance Care Plan

83%1,786 patients4/55-star benchmark: 100%

Melanoma: Continuity of Care - Recall System

100%206 patients

Preventive Care and Screening: Tobacco Use: Screening and Cessation Intervention

Patients combinedPopulations: 100% · 2,033 patients

Patients screened: 100% · 2,033 patients

98%46 patients4/55-star benchmark: 100%

Provide Patients Electronic Access to Their Health Information

96%2,089 patients4/55-star benchmark: 100%

Tobacco Use and Help with Quitting Among Adolescents

97%491 patients4/55-star benchmark: 100%

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.

Other Providers at the Same Location NPPES 3

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

DR. JEANETTE KAMELL MITCHELL MD

Dermatology

55 ROLLING OAKS DR STE 200
THOUSAND OAKS, CA 91361

Los Angeles County (805) 497-7529

MICHAEL G BODNAR MD

Dermatology

55 ROLLING OAKS DR STE 200
THOUSAND OAKS, CA 91361

Los Angeles County (805) 497-7529

RALPH M KAMELL MD

Dermatology

55 ROLLING OAKS DR STE 200
THOUSAND OAKS, CA 91361

Los Angeles County (805) 497-7529

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 Rietkerk's NPI number?

The NPI number for William Rietkerk is 1720311400. It was assigned to this individual provider in the NPPES registry on September 11, 2009.

Where is William Rietkerk located?

William Rietkerk practices at 55 Rolling Oaks Dr Ste 200, Thousand Oaks, CA 91361. The listed phone number is (212) 661-3376.

What is William Rietkerk's specialty?

The primary specialty registered for this NPI is Dermatology with taxonomy code 207N00000X.

Is William Rietkerk enrolled in Medicare?

Yes. William Rietkerk 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 organization bills Medicare for William Rietkerk's services?

According to the CMS Revalidation Reassignment List (October 2026 release), William Rietkerk reassigns Medicare benefits to J Robert West, M.D., Inc (Newport Beach, CA). The 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 Rietkerk's services. Reassignment records can lag staffing changes; confirm current arrangements with the organization.

What insurance does William Rietkerk accept?

Health plans from UnitedHealthcare list William Rietkerk as in-network in at least one marketplace plan. Coverage varies by plan and year; verify with the insurer or the provider before a visit.

When was this NPI record last updated?

The NPPES record for William Rietkerk was last updated on July 21, 2022. NPI Profile syncs weekly with the NPPES registry data releases published by CMS. This NPI record was last updated 4 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.