Guillermo Lazo-Diaz, MD
Medical Oncology Physician · McAllen, TX
Guillermo Lazo-Diaz, MD is a medical oncology physician with a practice address in McAllen, Texas, and NPI 1760421101, issued on Jun 4, 2006. Check the license (Texas L0370, as entered in NPPES) on the Texas Medical Board; the Medicare figures below come from public CMS files.
- Name
- Guillermo Lazo-Diaz
- Credential
- MD
- Primary taxonomy
- Medical Oncology Physician 207RX0202X
- License number
- L0370 TX
Self-reported in NPPES; status is on the state search - Practice location
- 1901 S 2ND St, McAllen, TX 78503
- Phone
- (956) 687-5150
- Enumerated
- Jun 4, 2006
- Record last updated
- Dec 11, 2008 (not updated in 18 years: call before relying on the address or phone)
- Fax
- (956) 687-9546
- Medicaid IDs
- 42067104 TX
42067103 TX - Medicare enrollment
- Enrolled (PECOS I20040615000932); accepts Medicare assignment
- Telehealth
- Offers telehealth (CMS)
- Entity
- Type 1 · individual
8 nearest medical oncology physician records → All 547 in Texas → Look up another NPI →
Also registered at 1901 S 2ND St
A shared address usually means a shared clinic or building; it does not show who employs whom.
- Marcelo Boek, M.D.Hematology & Oncology Physician1134166788
- Debra Gillett, RN, FNP CNurse Practitioner1811931322
- Billie Marek, MDMedical Oncology Physician1346282209
- Suresh Ratnam, MDMedical Oncology Physician1649217639
- Alvaro Restrepo, MDMedical Oncology Physician1992748586
- Rogelio Salinas, MDRadiation Oncology Physician1942243837
Verify Guillermo Lazo-Diaz in five checks
- 1IdentityNPI record in CMS NPPESNPI lookupConfirmed in NPPES
- 2LicenseActive license and public ordersTexas Medical Board
Search for license L0370Check the board - 3Other statesLicenses and actions elsewhereDocInfo (FSMB)Not checked
- 4ExclusionsMedicare and Medicaid bansHHS-OIG exclusion listNot checked
- 5CertificationBoard certificationABMS AOA NCCPA AANPNot checked
81% more Medicare Part D claims than the average medical oncology physician in 2024
1,270 Medicare Part D claims for 276 beneficiaries, against an average of 703 among the 4,230 providers of this specialty who prescribed in Part D. Brand-name drugs were 26% of claims. 105 claims were for opioids.
Most prescribed
- Anastrozole211 claims
- Revlimid68 claims
- Hydrocodone-Acetaminophen67 claims
- Hydroxyurea66 claims
- Acyclovir61 claims
- Dexamethasone55 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): 89.4 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).
Industry payments in 2024: $442.17
15 payments; by number, the most common kind was food and beverage; the largest payer was E.R. Squibb & Sons, L.L.C. The 3,343 providers of this specialty with any payment received $11,773.47 on average. Payments are reported by manufacturers, not by the provider, and are not a sign of wrongdoing.
Source: CMS Open Payments, program year 2024 (openpaymentsdata.cms.gov); average among providers of this specialty with at least one payment.
Bills Medicare through one group practice
- Texas Oncology PAMcAllen, TX
Source: CMS Doctors and Clinicians National Downloadable File (the group practices a clinician bills Medicare through) (data.cms.gov).
Guillermo Lazo-Diaz among 547 medical oncology physician records in Texas
Guillermo Lazo-Diaz, MD is one of 547 medical oncology physician records with a practice address in Texas. 85% 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 6% of them.
- NPI issued2006 · 6% of these records are older, 45% newer
- In a Medicare fileYes · 85% of these records are
- In the CMS Doctors and Clinicians fileYes · 76% of these records are
- Graduated1993 · median 2000 among the 414 with a school on file
- Record last updated2008 · 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 207RX0202X and a Texas practice address; Medicare files: CMS Part D Prescribers 2024, MIPS 2023, Open Payments 2024, Doctors and Clinicians (data.cms.gov).
Medical Oncology Physician providers in Texas
There are 547 medical oncology physician records in Texas.
All 547 in Texas → Every provider in McAllen → Medical Oncology Physician nationwide →
The 8 medical oncology physician records with the nearest ZIP codes
- Joseph Litam, MDMcAllen, TX 785031528067469
- Billie Marek, MDMcAllen, TX 785031346282209
- Diane Duyen Nguyen, DOMcAllen, TX 785031023233756
- Suresh Ratnam, MDMcAllen, TX 785031649217639
- Alvaro Restrepo, MDMcAllen, TX 785031992748586
- Nirupama Shekar, M.D.McAllen, TX 785031689624405
- Balesh Sharma, MDBrownsville, TX 785211578505483
- Terence Herman, MDHarlingen, TX 785501124097498
Common questions
What is Guillermo Lazo-Diaz, MD's NPI number?
Guillermo Lazo-Diaz, MD's National Provider Identifier (NPI) is 1760421101, issued on Jun 4, 2006. An NPI identifies a provider in billing; it is not a license.
Where is Guillermo Lazo-Diaz, MD located?
The NPPES record lists a practice address at 1901 S 2ND St, McAllen, TX, 78503. Phone: (956) 687-5150. Providers update this record themselves, so call before visiting.
How can I verify Guillermo Lazo-Diaz, MD's license?
NPPES lists Texas license number L0370, as entered by the provider. Search the Texas Medical Board at https://profile.tmb.state.tx.us/Search.aspx. The NPPES record confirms identity only; the state search shows license status, expiration and public orders.
How much does Guillermo Lazo-Diaz, MD prescribe under Medicare Part D?
In 2024, Guillermo Lazo-Diaz, MD had 1,270 Medicare Part D claims for 276 beneficiaries; the average among medical oncology physician prescribers was 703. Part D covers Medicare prescriptions only.
What is Guillermo Lazo-Diaz, MD's MIPS final score?
The 2023 MIPS final score is 89.4 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.