Dr. Gregory Mark Ennis, MD
- Medicare services, 2019
- 1,179
- Part D claims, 2020
- 608
- Hospital affiliations
- 1
- Industry payments
- $105
- State license
- 1
- Practice address
- 725 Welch Road, Palo Alto, CA 94304
- Practice phone
- Call (650) 497-8000
- Professional email
- Get professional email
- Personal email
- Get personal email
- Mobile number
- Get mobile number
Primary practice
Find Dr. Ennis' professional email, personal email and mobile number
Dmand AI checks each channel through healthcare-specific waterfall enrichment. See what is on file with a free account, with practice phones, licenses and affiliations.
Dr. Gregory Mark Ennis is a family medicine physician in Palo Alto, California
Dr. Ennis practices at Lucile Packard Children's Hospital Stanford in Palo Alto, California, part of Stanford University.
Dr. Ennis' NPI, 1245220672, was assigned on October 26, 2005. Dr. Ennis holds Washington license MD60105263.
- NPI
- 1245220672NPI Registry (opens in a new tab)
- NPI enumeration date
- October 26, 2005
- NPI status
- Active
- Practice phone
- (650) 497-8000
- Professional email
- Get email
- Personal email
- Get email
- Mobile number
- Get number
- Sex
- Male
Sources: NPPES NPI Registry (CMS); Dmand AI Professional Profile Data; and Dmand AI Affiliation Data
Dr. Gregory Mark Ennis practices at Lucile Packard Children's Hospital Stanford in Palo Alto, California
Dr. Ennis' primary practice is Lucile Packard Children's Hospital Stanford, at 725 Welch Road, Palo Alto, CA 94304 in Santa Clara County. The practice phone is (650) 497-8000.
- Lucile Packard Children's Hospital Stanford725 Welch Road, Palo Alto, CA 94304 · Santa Clara CountyPhone(650) 497-8000
Source: Dmand AI Affiliation Data
Dr. Gregory Mark Ennis is affiliated with 1 site of care
Dr. Ennis' primary practice is Lucile Packard Children's Hospital Stanford in Palo Alto, California, part of Stanford University.
Sources: Dmand AI Affiliation Data; and Dmand AI Org Hierarchy Data
Dmand AI tracks the EHR system at Dr. Gregory Mark Ennis' practice
Dmand AI tracks the electronic health record (EHR) system at each site where Dr. Ennis practices. Vendor and product names are available with a free account.
| Site | EHR vendor and product |
|---|---|
| Lucile Packard Children's Hospital Stanford | Available with a free account |
Source: Dmand AI Technology Install Data
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Dmand AI maps EHR vendors, IT decision makers and buying committees across Stanford University and 6.2K+ hospitals, with verified contacts in the same login.
Dr. Gregory Mark Ennis is one of 15,680 family medicine physicians in California
Family medicine is Dr. Ennis' primary specialty in the NPI Registry, under taxonomy code 207Q00000X. Dr. Ennis is licensed in Washington.
Specialties and state licenses
- Family medicine, WashingtonPrimary
Family medicine physicians near Dr. Ennis
Counts of family medicine physicians with a Dmand AI profile, by place and practice. Each opens the list.
Sources: NPPES NPI Registry (CMS); Dmand AI Professional Profile Data; and Dmand AI Peer Benchmarks
Dr. Gregory Mark Ennis billed Medicare for 1,179 services in 2019
CMS data shows 1,179 Medicare services from Dr. Ennis across 15 procedure codes in 2019. Medicare paid $73,805 for them. Every service was in an office.
Dr. Ennis' Medicare services by type, 2018 to 2019
- 2018
- 2019
- Office and hospital visits
- 2018: 6482019: 6622%
- Other services
- 2018: 2552019: 17332%
- Tests and treatments
- 2018: 2292019: 14636%
- Drugs given in the office
- 2018: 1502019: 1407%
- Lab and pathology
- 2018: 02019: 35
- Surgery
- 2018: 02019: 23
Dr. Ennis compared with the California median for family medicine physicians, 2019
- Dr. Ennis
- California median
- Medicare services
- 1,179vs 2464.8 times
- Part D claims
- 608vs 83327% below
Medians across 15,349 family medicine physicians in California with Dmand AI profiles that report each measure.
Dr. Ennis' most billed Medicare procedure codes, 2019
CMS publishes codes billed for 11 or more Medicare patients. Each label is the code family; CPT descriptions are licensed by the AMA.
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Medicare shows one payer. Book a meeting to get commercial claims data for Dr. Ennis and other family medicine physicians in California.
Sources: Medicare Physician & Other Practitioners - by Provider and Service (CMS), 2024 data; and Dmand AI Peer Benchmarks
Dr. Gregory Mark Ennis' patients have a median age of 62
Across all payers, Dmand AI patient panel data puts Dr. Ennis' median patient age at 62, with 44% women.
Dr. Ennis' patients across all payers
Dmand AI patient panel data covers Medicare, Medicaid and commercial patients.
Patient panel by age, all payers
Median age 62
Patient panel by sex, all payers
- Women44%
- Men56%
Source: Dmand AI Patient Panel Data
Dr. Gregory Mark Ennis wrote 608 Medicare Part D claims in 2020
In 2020, Dr. Ennis wrote 608 Medicare Part D claims. They cover 25 drugs, with $10,605 in total drug cost. In 2019, CMS named 5,711 claims across 123 drugs.
Dr. Ennis' most prescribed drugs by claims, 2020
CMS names a drug when it has 11 or more claims. Share is of the claims for drugs CMS names.
Part D claims for drugs CMS names, 2019 to 2020
- 2019
- 2020
- Claims for drugs CMS names
- 2019: 5,7112020: 60889%
Drugs named by CMS: 25 in 2020, 123 in 2019.
Source: Medicare Part D Prescribers - by Provider and Drug (CMS), 2024 data, released May 6, 2026
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Dr. Gregory Mark Ennis received $105 in industry payments from 2016 to 2018
CMS Open Payments shows 7 general payments to Dr. Ennis from 6 drug and device companies from 2016 to 2018. Food and beverage make up the largest share, 100% of the total. GlaxoSmithKline, LLC. paid the most, $29.
General payments to Dr. Ennis by program year, 2016 to 2018
Companies that paid Dr. Ennis the most, 2016 to 2018
Share is of all general payments to this clinician.
Source: Open Payments (CMS), 2025 data, released July 7, 2026
Sources for Dr. Gregory Mark Ennis's profile data
| Data on this page | Source |
|---|---|
| NPI, name, sex, specialty and licenses | NPPES NPI Registry (CMS) (opens in a new tab)Dmand AI Professional Profile Data |
| Practice locations and phone | Dmand AI Affiliation Data |
| Primary practice, affiliations and health system | Dmand AI Affiliation DataDmand AI Org Hierarchy Data |
| Medicare services and procedure codes | Medicare Physician & Other Practitioners - by Provider and Service (CMS) (opens in a new tab) |
| State medians for the same specialty | Dmand AI Peer Benchmarks |
| Medicare patients and the all-payer patient panel | Dmand AI Patient Panel Data |
| Part D prescribing | Medicare Part D Prescribers - by Provider and Drug (CMS) (opens in a new tab) |
| Industry payments | Open Payments (CMS) (opens in a new tab) |
| EHR at each practice site | Dmand AI Technology Install Data |
| Similar physicians | Dmand AI Affiliation Data |
Data last refreshed October 2026Report an inaccuracyRemove my information
FAQ
Frequently asked questions about Dr. Gregory Mark Ennis
Spotted something out of date? Email hello@dmand.ai and we will check the record. Contact details live in the free trial.
What is Dr. Gregory Mark Ennis' NPI number?
Dr. Gregory Mark Ennis' NPI number is 1245220672. It was assigned on October 26, 2005, and it is active in the NPI Registry.
What kind of doctor is Dr. Gregory Mark Ennis?
Dr. Gregory Mark Ennis is a family medicine physician in Palo Alto, California. The primary specialty in the NPI Registry is Family Medicine Physician (taxonomy code 207Q00000X).
Where does Dr. Gregory Mark Ennis practice?
Dr. Ennis practices at 725 Welch Road, Palo Alto, CA 94304. Dr. Ennis' primary practice is Lucile Packard Children's Hospital Stanford in Palo Alto, California, part of Stanford University.
What is Dr. Gregory Mark Ennis' office phone number?
The practice phone on file for Dr. Ennis is (650) 497-8000.
What is Dr. Gregory Mark Ennis' medical license number?
Dr. Ennis holds Washington license MD60105263.
Which hospitals is Dr. Gregory Mark Ennis affiliated with?
Dr. Ennis practices at Lucile Packard Children's Hospital Stanford in Palo Alto, California.
Does Dr. Gregory Mark Ennis accept Medicare?
Yes. CMS data shows Dr. Ennis billed Medicare for 1,179 services in 2019.
What services does Dr. Gregory Mark Ennis bill to Medicare?
In 2019, Dr. Ennis' most billed Medicare services were office visit, established patient (99214), injected or infused drug (J3301) and infusion or chemotherapy administration (96372).
What drugs does Dr. Gregory Mark Ennis prescribe most?
In 2020 Medicare Part D data, Dr. Ennis' most prescribed drugs by claims were Lisinopril, Losartan Potassium and Levothyroxine Sodium.
Has Dr. Gregory Mark Ennis received payments from drug or device companies?
CMS Open Payments shows $105 in general payments to Dr. Ennis from 6 companies from 2016 to 2018. The largest total came from GlaxoSmithKline, LLC.
How long has Dr. Gregory Mark Ennis been practicing?
Dr. Ennis' NPI was assigned in 2005.
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