Dr. Mark L Williams , MD
Anesthesiology โข Dallas, TX
12222 Merit Dr Ste 600
Dallas, TX 752513294
This profile restates public CMS/NPPES data; T-MedInfo gives no medical advice — consult a licensed professional, and call 911 for emergencies.
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NPI assigned on July 6, 2006; this date does not establish years in practice.
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Published CMS data list 39 Original Medicare Part B services in 2024.
Source: CMS, Medicare Physician & Other Practitioners โ by Provider and Service, 2024. Published rows only; this is not a quality measure.
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Published Part B service records, 2024:
- 00670 โ Anesthesia for extensive surgery on spine: 14 service units.
- 36620 โ Insertion of artery tube for blood sampling or infusion through skin: 14 service units.
- 64488 โ Injection of local anesthetic for abdominal wall pain control on both sides using imaging guidance: 11 service units.
Source: CMS, Medicare Physician & Other Practitioners โ by Provider and Service, 2024. Units differ by code; these are not visits or a measure of quality.
CPTยฎ only copyright 2023 American Medical Association. All rights reserved. Service names are shortened from CPT Consumer Friendly Descriptors (CMS data, 2024). CPT notice
See the full table ยท Guide: How to read Medicare Part B data
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Published CMS data list 17 Medicare Part D prescriptions, including refills, in 2021.
Source: CMS, Medicare Part D Prescribers โ by Provider and Drug, 2021. Published rows only; this is not a quality measure.
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Published Part D records, 2021:
- Oxycodone-Acetaminophen (Oxycodone Hcl/Acetaminophen) โ 17 prescription fills, including refills.
Source: CMS, Medicare Part D Prescribers โ by Provider and Drug, 2021. Drug names come from pharmacy claims. Listing a drug here is not an endorsement or a recommendation.
See the full table ยท Guide: How to read Medicare Part D prescriber data
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Fewer Medicare Part B services than 75% of clinicians listed under Anesthesiology in Dallas, TX (2024, 836 clinicians with data). Median for this group: 90. Middle half: 46 to 191.
Fewer Medicare Part B services than 75% of clinicians listed under Anesthesiology in Texas (2024, 2,457 clinicians with data). Median for this group: 94. Middle half: 41 to 197.
Source: CMS, Medicare Physician & Other Practitioners โ by Provider and Service, 2024. Billing and prescribing volume is not a quality rating.
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Medicare Part B services went from 59 in 2020 to 39 in 2024.
Source: CMS, Medicare Physician & Other Practitioners โ by Provider and Service, 2020โ2024.
Practice Location & Contact Primary Location
12222 Merit Dr Ste 600
Dallas, TX 752513294
Matched by practice address or phone in NPPES. A shared address or phone does not confirm that this clinician works there.
NPPES lists 1 additional practice-address record in Phoenix, AZ. See the list
Source: CMS NPPES NPI Registry, practice location records; release date unavailable.
CMS Doctors and Clinicians lists 1 group name: U S Anesthesia Partners Of Texas, Pa. See the list
Source: CMS Doctors and Clinicians National Downloadable File, CMS release of October 2, 2026.
Listings do not confirm current availability, employment or a shared ownership network.
Medicare Profile & Education
Source: CMS Doctors and Clinicians National Downloadable File, CMS release of October 2, 2026
1986
What Public CMS Data Show
Anesthesiology: NPPES taxonomy is a reported classification, not proof of board certification.
Medicare patients
119 people with Original Medicare in 2024
It gives a sense of how many people with Medicare this clinician treated that year.
Source: CMS, Medicare Physician & Other Practitioners โ by Provider, 2024.
Medicare-allowed amount
About $12,368 in 2024
The total amount Medicare approved for these services in 2024. It includes what Medicare paid and what patients or their other insurance owed, such as the deductible and coinsurance.
It shows the total cost of this clinician's Original Medicare services under Medicare's fee rules.
What this does not show: Medicare-allowed amount
This is not the clinician's income. Part of it can go to a clinic or group practice, staff, equipment or drugs. It is not the price you will pay.
Source: CMS, Medicare Physician & Other Practitioners โ by Provider and Service, 2024.
Paid by Medicare
About $10,009 in 2024
The part of the Medicare-allowed amount that Medicare itself paid in 2024, after patients' deductibles and coinsurance.
The gap between the allowed amount and this number is roughly what patients and their other insurance paid.
What this does not show: Paid by Medicare
This is not the clinician's income and not a measure of quality.
Source: CMS, Medicare Physician & Other Practitioners โ by Provider and Service, 2024.
30-day fills
17 standardized 30-day fills in 2021
CMS converts prescriptions to 30-day supplies so they can be compared. A 90-day prescription counts as about three 30-day fills.
What this does not show: 30-day fills
It is not a count of patients and not a measure of quality.
Part D drug cost
$271 in 2021
The total cost of these prescriptions in 2021, paid by Medicare drug plans, patients and other payers together.
It shows the total spending on drugs this clinician prescribed, not what any one patient paid.
What this does not show: Part D drug cost
A higher cost often reflects the type of medicines a specialty uses. It is not your out-of-pocket cost and not a measure of quality.
Source: CMS, Medicare Part D Prescribers โ by Provider and Drug, 2021.
Open Payments general payments, program year 2025
All general payments: $43.76 across 2 records.
By nature of payment
- Education: $25.70 across 1 record.
- Food and Beverage: $18.06 across 1 record.
Reporting-company totals
- Merck Sharp & Dohme LLC: $25.70 across 1 record.
- Teva Pharmaceuticals USA, Inc.: $18.06 across 1 record.
A reported payment does not necessarily mean the financial relationship is improper and is not a measure of care quality. Clinicians can review and dispute these records.
Source: Calculated by T-MedInfo from CMS Open Payments general-payment records for program year 2025 (published June 30, 2026).
Years since graduation
40 years (graduated 1986)
CMS Doctors and Clinicians data list 1986 as the year this clinician finished professional school.
It tells you roughly how long ago the clinician finished school.
What this does not show: Years since graduation
It is not the number of years in practice, and more years does not mean better care.
Source: CMS Doctors and Clinicians National Downloadable File, CMS release of October 2, 2026.
NPI first issued
2006
The year this clinician's National Provider Identifier (NPI) was issued. An NPI is a unique 10-digit ID that US health care providers use for billing.
What this does not show: NPI first issued
NPIs have been issued only since 2005, so this year is not necessarily when the clinician started practicing.
Source: CMS NPPES NPI Registry.
Accepts Medicare assignment
CMS data list this clinician as accepting Medicare assignment. This means agreeing to take the Medicare-approved amount as full payment for covered services.
With Original Medicare, you usually pay only your deductible and coinsurance, and the office sends the claim to Medicare for you.
Medicare assignment applies to Original Medicare. It does not tell you whether the clinician is in a Medicare Advantage plan's network, accepts other insurance, or is taking new patients.
Source: CMS Doctors and Clinicians, CMS release of October 2, 2026; Medicare.gov, โDoes your provider accept Medicare as full payment?โ
No telehealth indicator
CMS shows this indicator only when recent Medicare claims include telehealth services. The clinician may still offer telehealth; ask the office.
Source: CMS, Telehealth Indicator on Medicare Care Compare (fact sheet, January 2023); CMS Doctors and Clinicians, CMS release of October 2, 2026.
Enrolled in Medicare (PECOS)
Dr. Williams has a Medicare enrollment record in PECOS, the CMS system clinicians use to enroll so they can bill Medicare or order services for people with Medicare.
It does not show whether the clinician accepts assignment, is in your plan's network, or is taking new patients.
Source: CMS Medicare Fee-For-Service Public Provider Enrollment (PECOS); CMS Order and Referring file.
Can order Medicare-covered services
CMS lists Dr. Williams as eligible to order or refer Medicare Part B clinical laboratory and imaging services, durable medical equipment (DME) and home health services for people with Medicare.
Medicare pays for these items and services only when they are ordered by an eligible clinician.
What this does not show: Can order Medicare-covered services
It does not mean the clinician offers these services directly.
Source: CMS Medicare Fee-For-Service Public Provider Enrollment (PECOS); CMS Order and Referring file.
Compared with the same specialty in Dallas and Texas
Billing and prescribing volume is not a quality rating.
Medicare Part B services
Fewer Medicare Part B services than 75% of clinicians listed under Anesthesiology in Dallas, TX (2024, 836 clinicians with data). Median for this group: 90. Middle half: 46 to 191.
Fewer Medicare Part B services than 75% of clinicians listed under Anesthesiology in Texas (2024, 2,457 clinicians with data). Median for this group: 94. Middle half: 41 to 197.
Medicare-allowed amount
Close to the middle for clinicians listed under Anesthesiology in Dallas, TX (2024, 836 clinicians with data). Median for this group: $12,189. Middle half: $5,763 to $24,793.
Close to the middle for clinicians listed under Anesthesiology in Texas (2024, 2,457 clinicians with data). Median for this group: $10,882. Middle half: $4,593 to $22,337.
Paid by Medicare
Close to the middle for clinicians listed under Anesthesiology in Dallas, TX (2024, 836 clinicians with data). Median for this group: $9,656. Middle half: $4,603 to $19,502.
Close to the middle for clinicians listed under Anesthesiology in Texas (2024, 2,457 clinicians with data). Median for this group: $8,552. Middle half: $3,614 to $17,495.
Medicare Part D
Comparisons use 2024 data. The latest CMS data for Dr. Williams are from 2021.
1,415 active clinicians are listed under Anesthesiology with a practice address in Dallas, TX (4,666 in Texas).
Addresses are self-reported to NPPES and may be out of date.
Telehealth indicator in Dallas
0.7% of these 1,415 clinicians have the CMS telehealth indicator.
76% of these 1,415 clinicians are listed by CMS as accepting Medicare assignment.
CMS data by year
Changes may reflect reporting, coverage or privacy limits, not changes in care quality.
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Medicare Part B services
Medicare Part B services decreased 34% from 59 in 2020 to 39 in 2024.
- 2020: 59
- 2021: 98
- 2022: 37
- 2023: 48
- 2024: 39
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Medicare-allowed amount
Medicare-allowed amount increased 132% from $5,338 in 2020 to $12,368 in 2024.
- 2020: $5,338
- 2021: $21,947
- 2022: $15,089
- 2023: $21,158
- 2024: $12,368
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Paid by Medicare
Paid by Medicare increased 134% from $4,272 in 2020 to $10,009 in 2024.
- 2020: $4,272
- 2021: $17,573
- 2022: $12,048
- 2023: $16,859
- 2024: $10,009
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Medicare Part D prescriptions
Medicare Part D prescriptions decreased 39% from 28 in 2015 to 17 in 2021.
- 2015: 28
- 2016: 12
- 2017: 13
- 2019: 13
- 2021: 17
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30-day fills
30-day fills decreased 39% from 28 in 2015 to 17 in 2021.
- 2015: 28
- 2016: 12
- 2017: 13
- 2019: 13
- 2021: 17
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Part D drug cost
Part D drug cost went from $308 in 2015 to $271 in 2021.
- 2015: $308
- 2016: $231
- 2017: $128
- 2019: $137
- 2021: $271
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Industry payments (Open Payments)
Industry payments (Open Payments) went from $14.08 in 2020 to $43.76 in 2025.
- 2020: $14.08
- 2025: $43.76
Sources: CMS Medicare Physician & Other Practitioners (2024), CMS Medicare Part D Prescribers (2021), CMS Open Payments (2025), CMS Doctors and Clinicians, CMS release of October 2, 2026, CMS NPPES NPI Registry. Specialty names follow the NUCC Health Care Provider Taxonomy.
Text: T-MedInfo ยท Report an error.
Pharma & Medical Device Financial Disclosures
Payments and other transfers of value that drug and medical device companies reported to CMS Open Payments
Program year 2025 (payments made January 1 โ December 31, 2025): fewer than 11 records totaling $43.76.
| Manufacturer | Payment Nature | Product | Type | Amount ($) |
|---|---|---|---|---|
| Merck Sharp & Dohme LLC |
Education
In-kind items and services
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BRIDION | General | $25.70 |
| Teva Pharmaceuticals USA, Inc. |
Food and Beverage
In-kind items and services
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AUSTEDO XR | General | $18.06 |
Source: CMS Open Payments, program year 2025, released June 30, 2026.
Performed Procedures & Service Volume
CPTยฎ is a registered trademark of the American Medical Association. CPT codes, descriptions and other data only are copyright 2016โ2023 American Medical Association. All rights reserved. Applicable FARS/HHSARS apply. Descriptions of CPT codes are the AMA's CPT Consumer Friendly Descriptors as published by CMS in the Medicare Physician & Other Practitioners โ by Provider and Service data, 2017โ2024; they are plain-language summaries, not for clinical coding or documentation. HCPCS Level II codes and descriptions are from CMS. Fee schedules, relative value units, conversion factors and/or related components are not assigned by the AMA, are not part of CPT, and the AMA is not recommending their use. The AMA does not directly or indirectly practice medicine or dispense medical services. The AMA assumes no liability for data contained or not contained herein.
| HCPCS Code | Services | Patients | Submitted Charge | Medicare Allowed |
|---|---|---|---|---|
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00670
Anesthesia for extensive surgery on spine
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14 | 14 | $5311.43 | $784.12 |
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36620
Insertion of artery tube for blood sampling or infusion through skin
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14 | 14 | $192.00 | $44.74 |
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64488
Injection of local anesthetic for abdominal wall pain control on both sides using imaging guidance
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11 | 11 | $299.00 | $69.42 |
Source: CMS Part B by Provider and Service, 2024; services under 11 beneficiaries omitted by CMS. Privacy limits
Submitted charges are billed amounts, not a price quote for your visit.
Medicare Part D Prescribing Profile & Medications
Medicare Part D prescriptions filled, including refills, in 2021.
| Brand Name | Generic Name | Prescriptions | Day Supply | Total Cost | Patients |
|---|---|---|---|---|---|
| Oxycodone-Acetaminophen | Oxycodone Hcl/Acetaminophen | 17 | 363 | $270.68 | โ |
Source: CMS Part D by Provider and Drug, 2021; rows below 11 claims omitted by CMS; volume isn’t quality. Privacy limits
Specialties & License Numbers Reported to NPPES
Self-certified to NPPES: 2026-04-22NUCC Taxonomy Code: 207L00000X
An anesthesiologist is trained to provide pain relief and maintenance, or restoration, of a stable condition during and immediately following an operation or an obstetric or diagnostic procedure. The anesthesiologist assesses the risk of the patient undergoing surgery and optimizes the patient's condition prior to, during and after surgery. In addition to these management responsibilities, the anesthesiologist provides medical management and consultation in pain management and critical care medicine. Anesthesiologists diagnose and treat acute, long-standing and cancer pain problems; diagnose and treat patients with critical illnesses or severe injuries; direct resuscitation in the care of patients with cardiac or respiratory emergencies, including the need for artificial ventilation; and supervise post-anesthesia recovery.
NUCC Taxonomy Code: 207L00000X
An anesthesiologist is trained to provide pain relief and maintenance, or restoration, of a stable condition during and immediately following an operation or an obstetric or diagnostic procedure. The anesthesiologist assesses the risk of the patient undergoing surgery and optimizes the patient's condition prior to, during and after surgery. In addition to these management responsibilities, the anesthesiologist provides medical management and consultation in pain management and critical care medicine. Anesthesiologists diagnose and treat acute, long-standing and cancer pain problems; diagnose and treat patients with critical illnesses or severe injuries; direct resuscitation in the care of patients with cardiac or respiratory emergencies, including the need for artificial ventilation; and supervise post-anesthesia recovery.
Medicare (PECOS) Enrollment & Ordering Eligibility
Source: CMS PECOSPRACTITIONER - ANESTHESIOLOGY
I20260421004157
TX
4183780943
Sources: CMS Provider Enrollment and Order and Referring. Medicare enrollment is a billing status, not an accreditation or quality rating.
Medicare Group Practice Enrollments
Source: CMS Doctors and Clinicians National Downloadable File, CMS release of October 2, 2026
U S Anesthesia Partners Of Texas, Pa
2831 E President George Bush Hwy, Richardson, TX 750823561
Phone: 4692040702
Secondary Practice Locations
250 E Dunlap Ave
Phoenix, AZ 85020
Phone: 6022739333
Clinicians Sharing This Practice Address or Phone
Clinicians sharing this NPPES address, phone or fax; a shared contact does not mean they work together.
Anesthesiology
Doctor of Medicine (M.D.)
Anesthesiology
Doctor of Medicine (M.D.)
Nurse Anesthetist, Certified Registered
Certified Registered Nurse Anesthetist
Anesthesiology
Doctor of Medicine (M.D.)
Anesthesiology
Doctor of Medicine (M.D.)
Anesthesiologist Assistant
Career & Practice History Timeline
Changes recorded in monthly NPPES data files: addresses, names, credentials, specialties and NPI status
Registered at 12222 MERIT DR STE 600, DALLAS, TX 752513294 (Tel: 9727155000)
Additional practice office at 250 E DUNLAP AVE, PHOENIX, AZ 85020
NPI status registered as active in NPPES database
Registered at 250 E DUNLAP AVE, PHOENIX, AZ 85020 (Tel: 6022739333)
Registered at PO BOX 13385, SCOTTSDALE, AZ 852673385 (Tel: 4806099300)
Recorded as MARK WILLIAMS, MD
Anesthesiology (license number reported to NPPES: AZ 22063)
First registered as active Individual Practitioner in NPPES Database.
NPI Administrative Meta
Other Anesthesiology Specialists in Dallas
- Dr. George Alvarez, MD
- Dr. Benito Irizarry, MD
- Dr. Mark Villarreal, MD
- Dr. Richard Wingo, MD
- Dr. Lee Lunsford, MD
- Dr. Kenneth Wilhelm, MD
Mailing Address
Po Box 13385
Scottsdale, AZ 852673385
Phone: 4806099300