CLAY HUGHES NAPPER M.D.
NPI 1053352815
Radiology - Diagnostic Radiology in San Mateo, CA

Q: What is Clay Napper's NPI number?

The NPI number for Clay Napper is 1053352815. It was assigned to this individual provider in the NPPES registry on June 10, 2006.

Q: Where is Clay Napper located?

Clay Napper practices at 100 S San Mateo Dr, San Mateo, CA 94401. The listed phone number is (650) 696-4515.

Q: What is Clay Napper's specialty?

The primary specialty registered for this NPI is Radiology, specializing in Diagnostic Radiology, with taxonomy code 2085R0202X.

Q: Is Clay Napper enrolled in Medicare?

Yes. Clay Napper 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.

Q: Which organizations bill Medicare for Clay Napper's services?

According to the CMS Revalidation Reassignment List (October 2026 release), Clay Napper reassigns Medicare benefits to 2 organizations: San Mateo County (San Mateo, CA) and California Advanced Imaging Medical Associates Inc (San Francisco, CA). 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 Clay Napper's services. Reassignment records can lag staffing changes; confirm current arrangements with the organization.

Q: When was this NPI record last updated?

The NPPES record for Clay Napper was last updated on March 19, 2021. NPI Profile syncs weekly with the NPPES registry data releases published by CMS. This NPI record was last updated 5 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 June 10, 2006PECOS EnrolledAccepts Medicare Assignment

100 S SAN MATEO DR, SAN MATEO, CA 94401(650) 696-4515(650) 696-4626 Get Directions Write a Review

NPPES record last updated: March 19, 2021. Verified against the NPPES registry weekly; last sync: October 18, 2026.

On this page

About Clay Hughes Napper M.d. NPPES

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

CLAY HUGHES NAPPER M.D. (NPI 1053352815) is an individual diagnostic radiology provider in San Mateo, California, licensed in California (G78045) and active in the NPI registry since June 2006. He is enrolled in Medicare PECOS, maintains 4 additional practice locations, and is a graduate of Wake Forest University School Of Medicine (1992).

NPPES Registry Identity

NPI1053352815

Entity TypeIndividualMale

Primary Taxonomy2085R0202X

Provider Legal NameCLAY HUGHES NAPPERCredential: M.D.

Location Address100 S SAN MATEO DRSan Mateo, CA 94401-3805

Mailing AddressP.o. Box 6102Novato, CA 94948-6102 · (415) 884-3418 · Fax (415) 883-8082

Phone(650) 696-4515

Fax(650) 696-4626

Sole ProprietorNo

Medical School CMSWake Forest University School Of MedicineGraduated 1992

Enumeration DateJune 10, 2006

Last NPPES UpdateMarch 19, 2021

NPPES CertifiedMarch 18, 2021

✔ NPI 1053352815 is a valid, active identifier and passes the ISO check-digit test.

Specialties & Licenses

★ Primary SpecialtyRadiology · Diagnostic RadiologyAllopathic & Osteopathic Physicians

Taxonomy Code2085R0202X

License✔ Licensed in CA · G78045

Definition

A radiologist who utilizes x-ray, radionuclides, ultrasound and electromagnetic radiation to diagnose and treat disease.

100 S SAN MATEO DR, San Mateo, CA 94401

Open in Google Maps ↗

Secondary Practice Locations 4

Location 1935 El Camino RealSouth San Francisco, CA 94080-3203 · Phone (650) 873-1050 · Fax (650) 873-2174

Location 2222 W 39th AveSan Mateo, CA 94403-4364 · Phone (650) 573-2222 · Fax (650) 573-2122

Location 31720 El Camino Real Ste 118Burlingame, CA 94010-3225 · Phone (650) 696-7850 · Fax (650) 696-3677

Location 41501 Trousdale DrBurlingame, CA 94010-4506 · Phone (650) 696-5515 · Fax (650) 696-5280

Other Identifiers 2

Medicaid00G780450CA

Other300121751CA · Railroad Medicare

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

Clay Hughes Napper 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 ID941372429

PECOS Enrollment IDI20080627000143

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

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

San Mateo County

1.4 mi

Community/Behavioral Health

1950 ALAMEDA DE LAS PULGAS
San Mateo, CA 94403

Reassigned Medicare billing, California enrollment
Medicare enrollment name: County Of San Mateo
597 clinicians in this Medicare group

NPI 1710908272 (650) 573-3571

California Advanced Imaging Medical Associates Inc

16 mi

Diagnostic Radiology

1101 VAN NESS AVE
San Francisco, CA 94109

Reassigned Medicare billing, California enrollment
96 clinicians in this Medicare group

NPI 1881646909 (415) 600-6000

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 47

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.

X-ray of chest, 1 view 71045

A chest X-ray, 1 view, is a quick, painless test that produces images of the structures within your chest, such as your heart, lungs, and blood vessels. It helps in diagnosing conditions like pneumonia, heart problems, or lung cancer. You'll stand in front of a machine that emits X-rays, which pass through your body to create the image.

473 services422 patients

Ct scan head or brain without contrast 70450

A CT scan of the head or brain without contrast is a non-invasive imaging procedure. It uses X-rays to create detailed pictures of your brain, skull, and other structures inside your head. It helps to detect conditions like strokes, tumors, or injuries. No dye (contrast) is used in this test.

202 services196 patients

X-ray of chest, 2 views 71046

A chest X-ray, 2 views, is a quick, painless test that creates pictures of the structures inside your chest, such as your heart, lungs, and blood vessels. Two different angles are used to get a comprehensive view. This helps in diagnosing conditions like pneumonia, heart problems, or lung cancer.

191 services186 patients

Dxa bone density measurement of hip, pelvis, spine 77080

A DXA bone density measurement is a simple, quick, and non-invasive procedure that assesses the strength of your bones. This test uses X-rays to measure the amount of minerals, mainly calcium, in the hip, pelvis, and spine. It helps in early detection of osteoporosis or other bone diseases.

179 services179 patients

Ct scan of abdomen and pelvis with contrast 74177

A CT scan of the abdomen and pelvis with contrast is an imaging procedure. A special dye, called contrast, is used to make certain areas more visible. This can help identify issues such as infections, tumors, or other abnormalities. The procedure is painless and usually takes about 30 minutes.

110 services105 patients

Nuclear medicine study from skull base to mid-thigh with ct scan 78815

A nuclear medicine study from skull base to mid-thigh with a CT scan involves using a small amount of radioactive material and CT imaging to examine body tissues and organs. This helps detect any abnormalities by providing detailed images of the body's internal structure.

96 services94 patients

Limited ultrasound scan of abdomen 76705

A limited ultrasound scan of the abdomen is a non-invasive imaging test. It uses sound waves to produce images of the abdominal organs such as the liver, gallbladder, spleen, pancreas, and kidneys. This helps to identify any abnormalities or issues.

88 services88 patients

Complete ultrasound scan behind abdominal cavity 76770

A complete ultrasound scan behind the abdominal cavity is a non-invasive imaging procedure. It uses sound waves to create pictures of the structures and organs located at the back of your abdomen. It helps in diagnosing health conditions and monitoring ongoing treatments.

73 services73 patients

Screening 3d breast mammography 77063

Screening 3D breast mammography is a procedure that uses low-dose X-rays to create detailed images of the breast. This allows for early detection of any unusual changes or growths. It's a non-invasive, outpatient procedure that typically takes about 30 minutes.

62 services62 patients

Screening mammography 77067

Screening mammography is a preventative measure that uses low-dose X-rays to take images of the chest area. It's a key tool in early detection of abnormalities, helping to identify issues before they become symptomatic. It is recommended annually for certain age groups.

62 services62 patients

X-ray of chest, 2 views 71046

59 services58 patients

Ultrasound scan of head and neck soft tissue 76536

An ultrasound scan of the head and neck soft tissue is a non-invasive procedure that uses sound waves to create images of the soft tissues in these areas. It helps identify any abnormalities or issues, such as tumors, cysts, or infections. It's painless and doesn't involve radiation.

51 services51 patients

Dxa bone density measurement of forearm, finger, hand, or foot 77081

A DXA bone density measurement of the forearm, finger, hand, or foot is a non-invasive procedure that uses X-rays to measure the amount of calcium and other minerals in your bones. This test helps to assess the strength of your bones and your risk of fractures.

51 services51 patients

X-ray of shoulder, minimum of 2 views 73030

An X-ray of the shoulder, with a minimum of 2 views, is a non-invasive imaging test. It uses a small amount of radiation to produce images of your shoulder bones. This helps in diagnosing conditions like fractures, arthritis, or other abnormalities. The procedure is quick and painless.

47 services45 patients

Ct scan of chest with contrast 71260

A CT scan of the chest with contrast is an imaging procedure. A special dye (contrast) is used to highlight specific areas in your body, providing clearer pictures of your chest. This helps in diagnosing conditions related to your lungs, heart, and other chest structures.

44 services42 patients

Ct scan of blood vessels of chest with contrast 71275

A CT scan of the chest with contrast is a non-invasive imaging test. It uses X-rays and a special dye to get detailed images of your blood vessels in the chest. This helps in diagnosing conditions related to heart and lungs.

42 services42 patients

Ct scan of chest without contrast 71250

A CT scan of the chest without contrast is a non-invasive imaging procedure. It uses special X-ray equipment to produce detailed images of your chest area, including your lungs and heart. It can help diagnose conditions such as lung diseases or heart disorders. It doesn't involve any dyes or contrast agents.

41 services41 patients

Ct scan of abdomen and pelvis without contrast 74176

A CT scan of the abdomen and pelvis is a non-invasive medical test. It uses special X-ray equipment to create detailed images of your abdominal and pelvic areas. This helps doctors examine organs, tissues, and vessels. No contrast dye is used in this procedure.

40 services40 patients

X-ray of shoulder, minimum of 2 views 73030

39 services35 patients

X-ray of hip, 2-3 views 73502

An X-ray of the hip with 2-3 views is a non-invasive imaging test. It uses a small amount of radiation to produce pictures of the hip joint. These images help in diagnosing conditions like fractures, arthritis, or other abnormalities. The process is quick and painless.

39 services39 patients

X-ray of knee, 3 views 73562

An X-ray of the knee, 3 views, is a non-invasive imaging test. It uses a small amount of radiation to produce images of the knee from three different angles. This helps medical professionals to diagnose and monitor conditions like arthritis, fractures, or infections. The process is quick and painless.

39 services31 patients

Complete ultrasound scan of pelvis 76856

A complete ultrasound scan of the pelvis is a safe, non-invasive imaging procedure. It uses sound waves to create pictures of your lower abdomen area, helping doctors to evaluate and diagnose any potential issues. It's painless and usually takes about 30 minutes.

38 services38 patients

Ultrasound scan of uterus, ovaries, tubes, cervix and pelvic area through vagina 76830

An ultrasound scan of the lower abdominal region is a safe, non-invasive procedure that uses sound waves to create images of internal structures. This helps in checking the health of reproductive organs and detecting any abnormalities. The scan is done via a small probe inserted into the body.

37 services37 patients

X-ray of hip, 2-3 views 73502

36 services36 patients

Ct scan of upper spine without contrast 72125

A CT scan of the upper spine without contrast is a non-invasive imaging test that uses X-rays to capture detailed images of your neck and upper back. It helps in identifying issues like fractures, tumors, or infections. No dye (contrast) is used in this scan.

35 services35 patients

X-ray of knee, 3 views 73562

35 services35 patients

X-ray of lower and sacral spine, 2-3 views 72100

An X-ray of the lower and sacral spine involves capturing images of your lower back area, including the tailbone. This procedure helps in identifying problems like fractures, infections, or deformities. 2-3 different angle views provide a comprehensive picture.

32 services32 patients

X-ray of abdomen, 1 view 74018

An X-ray of the abdomen, 1 view, is a quick and painless imaging test. It uses a small amount of radiation to produce images of the structures in your abdomen, such as the stomach, liver, and intestines. This can help identify issues like blockages, infections, or injuries.

31 services28 patients

X-ray of knee, 1-2 views 73560

An X-ray of the knee with 1-2 views is a quick, painless test that produces images of the knee bones. It helps identify fractures, infections, or changes in the knee joint. During the procedure, you'll be asked to stay still while the X-ray machine captures the images.

28 services28 patients

Complete ultrasound scan of abdomen 76700

A complete ultrasound scan of the abdomen is a non-invasive imaging procedure. It uses sound waves to produce images of the organs in your abdomen, such as the liver, gallbladder, spleen, pancreas, and kidneys. It helps in diagnosing, monitoring, and planning treatments.

27 services27 patients

Ct scan of blood vessels of head with contrast 70496

A CT scan of the head's blood vessels with contrast is a diagnostic procedure. A special dye (contrast) is injected into your body to make the blood vessels visible on the scan. This helps identify issues like blockages or abnormalities in your head's blood vessels.

23 services23 patients

Ct scan of blood vessels of neck with contrast 70498

A CT scan of the neck's blood vessels with contrast is a diagnostic procedure. It uses X-rays and a special dye to create detailed images of your neck's blood vessels. This helps doctors detect issues such as blockages or abnormalities.

23 services23 patients

X-ray of hand, minimum of 3 views 73130

An X-ray of the hand, minimum of 3 views, is a non-invasive imaging test. It uses a small amount of radiation to produce images of the bones in your hand from different angles. This helps in diagnosing fractures, infections, arthritis, or other abnormalities. It's quick and painless.

23 services19 patients

Ct scan of abdomen and pelvis before and after contrast 74178

A CT scan of your abdomen and pelvis with and without contrast helps visualize your internal organs better. Contrast is a special dye that improves the clarity of the images. It's taken orally or injected into your veins before the scan. The process is painless and quick.

21 services20 patients

Low dose ct scan of chest for lung cancer screening 71271

A low-dose CT scan of the chest is a quick, painless procedure that uses a small amount of radiation to create detailed images of your lungs. It's a key tool for early detection of lung cancer, especially for those at high risk.

18 services18 patients

X-ray of knee, 4 or more views 73564

An X-ray of the knee, 4 or more views, is a non-invasive imaging test. It involves capturing multiple images of your knee from different angles. This helps in diagnosing conditions such as fractures, arthritis, or infections. The procedure is quick and painless.

18 services15 patients

X-ray of ankle, minimum of 3 views 73610

An ankle X-ray is a quick, painless imaging test. It involves capturing at least three different images or 'views' of your ankle using small amounts of radiation. These images help identify any abnormalities or injuries, such as fractures or arthritis.

17 services15 patients

X-ray of hip, 1 view 73501

An X-ray of the hip, 1 view, is a quick, painless test where a small amount of radiation is used to produce images of the hip joint. This helps in diagnosing conditions like arthritis or fractures. You'll be positioned so that the X-ray machine can capture the best image of your hip.

15 services14 patients

X-ray of foot, minimum of 3 views 73630

An X-ray of the foot, minimum of 3 views, is a non-invasive imaging test. It uses a small amount of radiation to produce images of the bones and tissues in your foot. This helps to identify fractures, infections, or other abnormalities. Multiple views ensure a comprehensive examination.

15 services13 patients

Nuclear medicine study whole body with ct scan 78816

A Nuclear Medicine Study with a CT Scan is a diagnostic procedure. It uses a small amount of radioactive substance and a CT scan to create detailed images of your body. These images help doctors diagnose, monitor, and treat various conditions.

15 services13 patients

X-ray of pelvis, 1-2 views 72170

An X-ray of the pelvis, 1-2 views, is a quick and painless imaging test. It uses a small amount of radiation to produce images of the lower part of your torso. These images help to detect any abnormalities or injuries in your hip bones and surrounding structures.

14 services14 patients

X-ray of wrist, minimum of 3 views 73110

An X-ray of the wrist, minimum of 3 views, is a diagnostic procedure that uses radiation to create images of your wrist from different angles. This helps detect fractures, infections, or other abnormalities for accurate diagnosis and treatment planning.

14 services12 patients

X-ray of ankle, minimum of 3 views 73610

14 services14 patients

X-ray of foot, minimum of 3 views 73630

14 services11 patients

X-ray of lower and sacral spine, 2-3 views 72100

13 services13 patients

Ct scan of blood vessels of abdomen and pelvis with contrast 74174

A CT scan of the abdomen and pelvis with contrast is a medical imaging procedure. A special dye, called contrast, is used to make blood vessels more visible. The scan produces detailed images of your abdomen and pelvis, helping doctors to diagnose conditions or plan treatments.

13 services13 patients

X-ray of wrist, minimum of 3 views 73110

11 services11 patients

Physician Visit Costs CMS claims · ZIP area

Typical Medicare office-visit costs in the 94401 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

$104.51 typical visit price

range $69.00 – $202.35

Typical copayment $26.12 (range $17.25 – $50.58)

Most-billed visit code 99203

Established Patient

$84.91 typical visit price

range $23.44 – $166.46

Typical copayment $21.22 (range $5.86 – $41.61)

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.

Reported Quality Measures

Appropriate Follow-up Imaging for Incidental Abdominal Lesions

Percentage of final reports for abdominal imaging studies for asymptomatic patients aged 18 years and older with one or more of the following noted incidentally with follow_up imaging recommended: - Liver lesion =< 0.5 cm - Cystic kidney lesion < 1.0 cm -…

Lower rates are better for this measure.

74%46 patients

Radiation Consideration for Adult CT: Utilization of Dose Lowering Techniques

Percentage of final reports for patients aged 18 years and older undergoing CT with documentation that one or more of the following dose reduction techniques were used: - Automated exposure control - Adjustment of the mA and/or kV according to patient size -…

99%592 patients

Radiology: Stenosis Measurement in Carotid Imaging Reports

Percentage of final reports for carotid imaging studies (neck magnetic resonance angiography [MRA], neck computed tomography angiography [CTA], neck duplex ultrasound, carotid angiogram) performed that include direct or indirect reference to measurements of…

100%39 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.

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.

HARRIET BETH BOROFSKY M.D.

Radiology (Diagnostic Radiology)

100 S SAN MATEO DR
SAN MATEO, CA 94401

San Mateo County (650) 696-4140

SUTTER BAY HOSPITALS

Psychiatric Unit

100 S SAN MATEO DR
SAN MATEO, CA 94401

San Mateo County (650) 696-5400

QUAN MY TRAN DO

Family Medicine

100 S SAN MATEO DR
SAN MATEO, CA 94401

San Mateo County (650) 696-4515

VALERIE NOWAKOWSKI MD

Radiology (Radiation Oncology)

100 S SAN MATEO DR
SAN MATEO, CA 94401

San Mateo County (650) 336-8117

JEFFREY J. GUTTAS. MD, INC.

Allergy & Immunology

100 S SAN MATEO DR, STE 400
SAN MATEO, CA 94401

San Mateo County (650) 696-4101

DR. JEFFREY JOHN GUTTAS M.D.

Internal Medicine (Cardiovascular Disease)

100 S SAN MATEO DR, SUITE 400
SAN MATEO, CA 94401

San Mateo County (650) 696-4100

HAIDEE SUI DPT

Physical Therapist

100 S SAN MATEO DR
SAN MATEO, CA 94401

San Mateo County (650) 696-4315

MS. KIMBERLY J. ERLICH RN CPNP

Nurse Practitioner (Pediatrics)

100 S SAN MATEO DR, 3RD FLOOR, RM 3364
SAN MATEO, CA 94401

San Mateo County (650) 696-4595

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 Clay Napper's NPI number?

The NPI number for Clay Napper is 1053352815. It was assigned to this individual provider in the NPPES registry on June 10, 2006.

Where is Clay Napper located?

Clay Napper practices at 100 S San Mateo Dr, San Mateo, CA 94401. The listed phone number is (650) 696-4515.

What is Clay Napper's specialty?

The primary specialty registered for this NPI is Radiology, specializing in Diagnostic Radiology, with taxonomy code 2085R0202X.

Is Clay Napper enrolled in Medicare?

Yes. Clay Napper 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 Clay Napper's services?

According to the CMS Revalidation Reassignment List (October 2026 release), Clay Napper reassigns Medicare benefits to 2 organizations: San Mateo County (San Mateo, CA) and California Advanced Imaging Medical Associates Inc (San Francisco, CA). 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 Clay Napper'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 Clay Napper was last updated on March 19, 2021. NPI Profile syncs weekly with the NPPES registry data releases published by CMS. This NPI record was last updated 5 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.