Mark T. Fahlen, MD
Nephrology Physician · Modesto, CA
Mark T. Fahlen, MD is a nephrology physician with a practice address in Modesto, California, and NPI 1679539415, issued on Apr 21, 2006. Check the license (California A81212, as entered in NPPES) on the Medical Board of California; the Medicare figures below come from public CMS files.
- Name
- Mark T. Fahlen
- Credential
- MD
- Primary taxonomy
- Nephrology Physician 207RN0300X
- License number
- A81212 CA
Self-reported in NPPES; status is on the state search - Practice location
- 1400 Florida Ave, Modesto, CA 95350
- Phone
- (209) 544-2910
- Enumerated
- Apr 21, 2006
- Record last updated
- Aug 2, 2011 (not updated in 15 years: call before relying on the address or phone)
- Medicare enrollment
- Enrolled (PECOS I20040908000652); accepts Medicare assignment
- Medical or professional school
- Albany Medical College Of Union University, 1998
- Entity
- Type 1 · individual
8 nearest nephrology physician records → All 1,468 in California → Look up another NPI →
Also registered at 1400 Florida Ave
A shared address usually means a shared clinic or building; it does not show who employs whom.
- Carolyn Bradford, CNMAdvanced Practice Midwife1639269707
- Daniel CasanovaStudent in an Organized Health Care Education/Training Program1942987631
- Khary Dorsey, M.D.Obstetrics & Gynecology Physician1992017826
- Shannon DortonStudent in an Organized Health Care Education/Training Program1477058451
- John Emery, M.D.Specialist1225139199
- Irene Feaver, R.N. C.N.M.Advanced Practice Midwife1043375801
Verify Mark T. Fahlen in five checks
- 1IdentityNPI record in CMS NPPESNPI lookupConfirmed in NPPES
- 2LicenseActive license and public ordersMedical Board of California
Search for license A81212Check the board - 3Other statesLicenses and actions elsewhereDocInfo (FSMB)Not checked
- 4ExclusionsMedicare and Medicaid bansHHS-OIG exclusion listNot checked
- 5CertificationBoard certificationABMS AOA NCCPA AANPNot checked
2.6 times the Medicare Part D claims of the average nephrology physician in 2024
3,859 Medicare Part D claims for 294 beneficiaries, against an average of 1,465 among the 10,986 providers of this specialty who prescribed in Part D. 609 claims were for opioids.
Most prescribed
- Hydrocodone-Acetaminophen471 claims
- Prosol289 claims
- Furosemide208 claims
- Amlodipine Besylate144 claims
- Calcium Acetate107 claims
- Allopurinol105 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.
The MIPS final score for 2023 (Medicare payment program): 91.5 of 100
The Merit-based Incentive Payment System score is reported for this clinician. Four categories are weighted into the final score; the average among 454,083 clinicians with a measured score was 83.5.
Source: CMS Quality Payment Program, MIPS performance year 2023; category weights for 2023 (qpp.cms.gov).
Mark T. Fahlen among 1,468 nephrology physician records in California
Mark T. Fahlen, MD is one of 1,468 nephrology physician records with a practice address in California. 88% of them appear in a Medicare file (Part D prescribing, MIPS, Open Payments or Medicare group billing); this one does. Its NPI, issued in 2006, is newer than 10% of them.
- NPI issued2006 · 10% of these records are older, 48% newer
- In a Medicare fileYes · 88% of these records are
- In the CMS Doctors and Clinicians fileYes · 77% of these records are
- Graduated1998 · median 2001 among the 1,128 with a school on file
- Record last updated2011 · 62% of these records were not updated in five years or more
Source: CMS NPPES, file of Aug 9, 2026, every record with primary taxonomy 207RN0300X and a California practice address; Medicare files: CMS Part D Prescribers 2024, MIPS 2023, Open Payments 2024, Doctors and Clinicians (data.cms.gov).
Nephrology Physician providers in California
There are 1,468 nephrology physician records in California.
All 1,468 in California → Every provider in Modesto → Nephrology Physician nationwide →
The 8 nephrology physician records with the nearest ZIP codes
- Josephine Baisac, M.D.Modesto, CA 953501548223480
- Yuqiang Ge, M.D., PHDModesto, CA 953501740588680
- Kriengsak Itsara, MDModesto, CA 953501558363739
- Chang Joo, MDModesto, CA 953501508868787
- Kenneth Liu, MDModesto, CA 953501326042391
- Jose Santos, M.D.Modesto, CA 953501073577573
- Tong Sun, MDModesto, CA 953501629161336
- Ravikiran Vegasana, M.D.Modesto, CA 953501770738825
Common questions
What is Mark T. Fahlen, MD's NPI number?
Mark T. Fahlen, MD's National Provider Identifier (NPI) is 1679539415, issued on Apr 21, 2006. An NPI identifies a provider in billing; it is not a license.
Where is Mark T. Fahlen, MD located?
The NPPES record lists a practice address at 1400 Florida Ave, Modesto, CA, 95350. Phone: (209) 544-2910. Providers update this record themselves, so call before visiting.
How can I verify Mark T. Fahlen, MD's license?
NPPES lists California license number A81212, 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 Mark T. Fahlen, MD prescribe under Medicare Part D?
In 2024, Mark T. Fahlen, MD had 3,859 Medicare Part D claims for 294 beneficiaries; the average among nephrology physician prescribers was 1,465. Part D covers Medicare prescriptions only.
What is Mark T. Fahlen, MD's MIPS final score?
The 2023 MIPS final score is 91.5 of 100. The average among 454,083 clinicians with a measured score was 83.5.
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.