Allison Leigh Klein, M.D.
Family Medicine Physician · Fontana, CA
Allison Leigh Klein, M.D. is a family medicine physician with a practice address in Fontana, California, and NPI 1265664452, issued on Aug 20, 2009. Check the license (California A108521, as entered in NPPES) on the Medical Board of California; the Medicare figures below come from public CMS files.
- Name
- Allison Leigh Klein
- Credential
- M.D.
- Primary taxonomy
- Family Medicine Physician 207Q00000X
- License number
- A108521 CA
Self-reported in NPPES; status is on the state search - Practice location
- 9961 Sierra Ave, Fontana, CA 92335
- Phone
- (909) 427-5083
- Enumerated
- Aug 20, 2009
- Record last updated
- Dec 6, 2021 (not updated in 5 years: call before relying on the address or phone)
- Medicare enrollment
- Enrolled (PECOS I20100224000192); accepts Medicare assignment
- Medical or professional school
- Loma Linda University School Of Medicine, 2007
- Entity
- Type 1 · individual
8 nearest family medicine physician records → All 17,133 in California → Look up another NPI →
Also registered at 9961 Sierra Ave
A shared address usually means a shared clinic or building; it does not show who employs whom.
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Verify Allison Leigh Klein in five checks
- 1IdentityNPI record in CMS NPPESNPI lookupConfirmed in NPPES
- 2LicenseActive license and public ordersMedical Board of California
Search for license A108521Check the board - 3Other statesLicenses and actions elsewhereDocInfo (FSMB)Not checked
- 4ExclusionsMedicare and Medicaid bansHHS-OIG exclusion listNot checked
- 5CertificationBoard certificationABMS AOA NCCPA AANPNot checked
94% fewer Medicare Part D claims than the average family medicine physician in 2024
226 Medicare Part D claims for 144 beneficiaries, against an average of 3,544 among the 117,163 providers of this specialty who prescribed in Part D. 16 claims were for opioids.
Most prescribed
- Amlodipine Besylate13 claims
- Atorvastatin Calcium13 claims
- Hydrocodone-Acetaminophen11 claims
Source: CMS Medicare Part D Prescribers by Provider and Drug, 2024 (data.cms.gov). Part D covers prescriptions for Medicare patients only; drugs with fewer than 11 claims are not published.
Bills Medicare through one group practice
- Southern California Permanente Medical GroupColton, CA
Source: CMS Doctors and Clinicians National Downloadable File (the group practices a clinician bills Medicare through) (data.cms.gov).
Allison Leigh Klein among 17,133 family medicine physician records in California
Allison Leigh Klein, M.D. is one of 17,133 family medicine physician records with a practice address in California. 81% of them appear in a Medicare file (Part D prescribing, MIPS, Open Payments or Medicare group billing); this one does. Its NPI, issued in 2009, is newer than 58% of them.
- NPI issued2009 · 58% of these records are older, 40% newer
- In a Medicare fileYes · 81% of these records are
- In the CMS Doctors and Clinicians fileYes · 62% of these records are
- Graduated2007 · median 2005 among the 10,652 with a school on file
- Record last updated2021 · 58% of these records were not updated in five years or more
Source: CMS NPPES, file of Aug 9, 2026, every record with primary taxonomy 207Q00000X and a California practice address; Medicare files: CMS Part D Prescribers 2024, MIPS 2023, Open Payments 2024, Doctors and Clinicians (data.cms.gov).
198 family medicine physician records list a practice address in Fontana
They are 198 of the 3,012 NPPES records with a practice address in Fontana, and 17,133 family medicine physician records in California.
All 17,133 in California → Every provider in Fontana → Family Medicine Physician nationwide →
The 8 family medicine physician records with the nearest ZIP codes
- Frances Burke, MDFontana, CA 923351972674901
- Nathan Carlson, M.D.Fontana, CA 923351144212929
- Christine Carlson, MDFontana, CA 923351386612299
- Thawat Eosakul, M.D.Fontana, CA 923351811904519
- Diane Hom, MDFontana, CA 923351821169707
- Anissa Lacount, MDFontana, CA 923351609854397
- Rubin Lin, D.O.Fontana, CA 923351679678916
- Lannie Moy, PA-CFontana, CA 923351922037738
Common questions
What is Allison Leigh Klein, M.D.'s NPI number?
Allison Leigh Klein, M.D.'s National Provider Identifier (NPI) is 1265664452, issued on Aug 20, 2009. An NPI identifies a provider in billing; it is not a license.
Where is Allison Leigh Klein, M.D. located?
The NPPES record lists a practice address at 9961 Sierra Ave, Fontana, CA, 92335. Phone: (909) 427-5083. Providers update this record themselves, so call before visiting.
How can I verify Allison Leigh Klein, M.D.'s license?
NPPES lists California license number A108521, as entered by the provider. Search the Medical Board of California at https://www.mbc.ca.gov/License-Verification/default.aspx. The NPPES record confirms identity only; the state search shows license status, expiration and public orders.
How much does Allison Leigh Klein, M.D. prescribe under Medicare Part D?
In 2024, Allison Leigh Klein, M.D. had 226 Medicare Part D claims for 144 beneficiaries; the average among family medicine physician prescribers was 3,544. Part D covers Medicare prescriptions only.
Source: CMS National Plan and Provider Enumeration System (NPPES), file of Aug 9, 2026 (NPPES files on CMS.gov); NUCC Health Care Provider Taxonomy. Medicare files from data.cms.gov. An NPI identifies who bills; it is not a license.
Figures on PlainDoctor are read from the federal files each page names (CMS NPPES, Medicare Part D, MIPS, Open Payments; the HHS-OIG exclusion list only as counts) and from Census population estimates, with the file date shown beside them. See our editorial standards & corrections policy, the methodology behind these numbers, or report a data error. Data current as of Aug 9, 2026.