Dr. Mark Francis Grenquist, DO
- Medicare services, 2024
- 299
- Medicare patients, 2024
- 109
- Part D claims, 2024
- 194
- Hospital affiliations
- 3
- Industry payments
- $14
- Practice address
- 200 N Madison, Marshall, MI 49068
- Practice phone
- Call (269) 781-4271
- Professional email
- Get professional email
- Personal email
- Get personal email
- Mobile number
- Get mobile number
Primary practice
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Dr. Mark Francis Grenquist is an internist in Marshall, Michigan
Dr. Grenquist practices at Oaklawn Hospital in Marshall, Michigan, part of Oaklawn Hospital.
Dr. Grenquist's NPI, 1942300454, was assigned on September 24, 2006. Dr. Grenquist graduated from Michigan State University College of Human Medicine in 2001. Dr. Grenquist holds Michigan license 5101014936.
- NPI
- 1942300454NPI Registry (opens in a new tab)
- Medicare PAC ID
- 9032179866
- NPI enumeration date
- September 24, 2006
- NPI status
- Active
- Accepts Medicare assignment
- Yes
- Practice phone
- (269) 781-4271
- Professional email
- Get email
- Personal email
- Get email
- Mobile number
- Get number
- Sex
- Male
- Estimated age
- 51
- Medical school graduation
- 2001
Sources: NPPES NPI Registry (CMS); Dmand AI Professional Profile Data; Dmand AI Affiliation Data; and Doctors and Clinicians National Downloadable File (CMS)
Dr. Mark Francis Grenquist practices at Oaklawn Hospital in Marshall, Michigan
Dr. Grenquist's primary practice is Oaklawn Hospital, at 200 N Madison, Marshall, MI 49068 in Calhoun County. The practice phone is (269) 781-4271.
- Oaklawn Hospital200 N Madison, Marshall, MI 49068 · Calhoun CountyPhone(269) 781-4271
Source: Dmand AI Affiliation Data
Dr. Mark Francis Grenquist is affiliated with 4 sites of care and 2 medical groups
Dr. Grenquist's primary practice is Oaklawn Hospital in Marshall, Michigan, part of Oaklawn Hospital. Dr. Grenquist is also affiliated with Chelsea Hospital. The medical group on file is Apogee Physicians. Dmand AI also links Dr. Grenquist to 1 more hospital, 1 group practice or clinic and 1 medical group, each named with a free account.
Sources: Dmand AI Affiliation Data; and Dmand AI Org Hierarchy Data
Dmand AI tracks the EHR system at Dr. Mark Francis Grenquist's practice
Dmand AI tracks the electronic health record (EHR) system at each site where Dr. Grenquist practices, 4 sites in all. Vendor and product names are available with a free account.
| Site | EHR vendor and product |
|---|---|
| Oaklawn Hospital | Available with a free account |
| +3 more sites and 1 medical group | Available with a free account |
Source: Dmand AI Technology Install Data
For health IT teams
Dmand AI maps EHR vendors, IT decision makers and buying committees across Oaklawn Hospital and 6.2K+ hospitals, with verified contacts in the same login.
Dr. Mark Francis Grenquist is one of 4,804 internists in Michigan
Internal medicine is Dr. Grenquist's primary specialty in the NPI Registry, under taxonomy code 207R00000X. Dr. Grenquist is licensed in Michigan.
Specialties and state licenses
- Internal medicine, MichiganPrimary
Internists near Dr. Grenquist
Counts of internists 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. Mark Francis Grenquist billed Medicare for 299 services in 2024
CMS data shows 299 Medicare services from Dr. Grenquist across 4 procedure codes in 2024, for 109 Medicare patients. Medicare paid $21,417 for them. Every service was in a facility, such as a hospital, rather than an office.
Dr. Grenquist's Medicare services by type, 2023 to 2024
- 2023
- 2024
- Office and hospital visits
- 2023: 3182024: 2996%
Dr. Grenquist compared with the Michigan median for internists, 2024
- Dr. Grenquist
- Michigan median
- Medicare services
- 299vs 42329% below
- Medicare patients
- 109vs 15931% below
- Part D claims
- 53vs 31483% below
Medians across 4,524 internists in Michigan with Dmand AI profiles that report each measure.
Dr. Grenquist's most billed Medicare procedure codes, 2024
CMS publishes codes billed for 11 or more Medicare patients. Each label is the code family; CPT descriptions are licensed by the AMA.
Need commercial claims for Dr. Grenquist?
Medicare shows one payer. Book a meeting to get commercial claims data for Dr. Grenquist and other internists in Michigan.
Sources: Medicare Physician & Other Practitioners - by Provider and Service (CMS), 2024 data; and Dmand AI Peer Benchmarks
Dr. Mark Francis Grenquist treated 109 Medicare patients in 2024, average age 77
CMS counts 109 Medicare patients who saw Dr. Grenquist in 2024. The largest group is 75 to 84, with 34 patients. 75% of them have high blood pressure, and 75% have high cholesterol. 29% are also on Medicaid. Their average risk score is 2.15, where 1.00 is the Medicare average, so they are sicker than most Medicare patients.
Across all payers, Dmand AI patient panel data puts Dr. Grenquist's median patient age at 73, with 54% women.
Dr. Grenquist's Medicare patients by age, 2024
CMS leaves out age groups with fewer than 11 patients.
Dr. Grenquist's Medicare patients by sex, 2024
- Women6761%
- Men4239%
Chronic conditions among Dr. Grenquist's Medicare patients, 2024
- High blood pressure75%
- High cholesterol75%
- Arthritis51%
- Chronic kidney disease50%
- Ischemic heart disease50%
- COPD48%
- Diabetes48%
- Mood disorders48%
Share of Medicare patients with each condition. A patient can have several.
Dr. Grenquist's patients across all payers
Dmand AI patient panel data covers Medicare, Medicaid and commercial patients.
Patient panel by age, all payers
Median age 73
Patient panel by sex, all payers
- Women54%
- Men46%
Sources: Dmand AI Patient Panel Data; and Medicare Physician & Other Practitioners - by Provider (CMS), 2024 data
Dr. Mark Francis Grenquist wrote 194 Medicare Part D claims in 2024
In 2024, Dr. Grenquist wrote 194 Medicare Part D claims for 104 patients. 93% of them were for generic drugs. CMS names the drug for 53 of them, across 3 drugs with 11 or more claims each, at $315 in total drug cost. In 2023, CMS named 11 claims across 1 drug.
Dr. Grenquist's Part D claims by kind of drug, 2024
- Generic181 claims93%
- Brand-name and other13 claims7%
Dr. Grenquist's most prescribed drugs by claims, 2024
CMS names a drug when it has 11 or more claims. Share is of the claims for drugs CMS names.
Drug classes CMS tracks in Dr. Grenquist's Part D claims, 2024
- Opioids6%12 of 194 claims
- Antibiotics31%60 of 194 claims
Share of all Part D claims for each drug class CMS reports on. Classes with no claims are left out.
Part D claims for drugs CMS names, 2023 to 2024
- 2023
- 2024
- Claims for drugs CMS names
- 2023: 112024: 53382%
Drugs named by CMS: 3 in 2024, 1 in 2023.
Sources: Medicare Part D Prescribers - by Provider and Drug (CMS), 2024 data, released May 6, 2026; and Medicare Part D Prescribers - by Provider (CMS), 2024 data
How Dr. Mark Francis Grenquist takes part in Medicare
Dr. Grenquist accepts Medicare assignment, so Medicare's approved amount is taken as full payment.
- Accepts Medicare assignment
- Yes
Source: Doctors and Clinicians National Downloadable File (CMS)
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Dr. Mark Francis Grenquist received $14 in industry payments in 2017
CMS Open Payments shows 1 general payment to Dr. Grenquist from 1 drug or device company in 2017. Food and beverage make up the largest share, 100% of the total. GlaxoSmithKline, LLC. paid the most, $14.
Companies that paid Dr. Grenquist the most, 2017 to 2017
Share is of all general payments to this clinician.
Source: Open Payments (CMS), 2025 data, released July 7, 2026
Dr. Mark Francis Grenquist graduated from Michigan State University College of Human Medicine
Dr. Grenquist graduated from Michigan State University College of Human Medicine in 2001.
- Medical school
Source: Dmand AI Professional Profile Data
Sources for Dr. Mark Francis Grenquist'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 DataMedicare Physician & Other Practitioners - by Provider (CMS) (opens in a new tab) |
| Part D prescribing | Medicare Part D Prescribers - by Provider and Drug (CMS) (opens in a new tab)Medicare Part D Prescribers - by Provider (CMS) (opens in a new tab) |
| MIPS scores, telehealth, assignment and procedure percentiles | Doctors and Clinicians National Downloadable File (CMS) (opens in a new tab) |
| Industry payments | Open Payments (CMS) (opens in a new tab) |
| Training, board certification and memberships | Dmand AI Professional Profile Data |
| 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. Mark Francis Grenquist
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. Mark Francis Grenquist's NPI number?
Dr. Mark Francis Grenquist's NPI number is 1942300454. It was assigned on September 24, 2006, and it is active in the NPI Registry.
What kind of doctor is Dr. Mark Francis Grenquist?
Dr. Mark Francis Grenquist is an internist in Marshall, Michigan. The primary specialty in the NPI Registry is Internal Medicine Physician (taxonomy code 207R00000X).
Where does Dr. Mark Francis Grenquist practice?
Dr. Grenquist practices at 200 N Madison, Marshall, MI 49068. Dr. Grenquist's primary practice is Oaklawn Hospital in Marshall, Michigan, part of Oaklawn Hospital. Dmand AI also links Dr. Grenquist to 1 hospital, 1 group practice or clinic and 1 medical group.
What is Dr. Mark Francis Grenquist's office phone number?
The practice phone on file for Dr. Grenquist is (269) 781-4271.
What is Dr. Mark Francis Grenquist's medical license number?
Dr. Grenquist holds Michigan license 5101014936.
Which hospitals is Dr. Mark Francis Grenquist affiliated with?
Dr. Grenquist practices at Oaklawn Hospital in Marshall, Michigan. Dr. Grenquist is also affiliated with Chelsea Hospital. Dmand AI links Dr. Grenquist to 1 more hospital.
What medical group is Dr. Mark Francis Grenquist part of?
Dr. Grenquist is linked to Apogee Physicians. Dmand AI links Dr. Grenquist to 1 more medical group.
Does Dr. Mark Francis Grenquist accept Medicare?
Yes. CMS data shows Dr. Grenquist billed Medicare for 299 services in 2024, and Dr. Grenquist accepts Medicare assignment.
How many Medicare patients does Dr. Mark Francis Grenquist see?
CMS counts 109 Medicare patients who saw Dr. Grenquist in 2024, with an average age of 77.
What services does Dr. Mark Francis Grenquist bill to Medicare?
In 2024, Dr. Grenquist's most billed Medicare services were hospital inpatient care (99232), hospital inpatient care (99239) and hospital inpatient care (99222).
Show 4 more questionsShow fewer questions
Where did Dr. Mark Francis Grenquist go to medical school?
Dr. Grenquist graduated from Michigan State University College of Human Medicine in 2001.
What drugs does Dr. Mark Francis Grenquist prescribe most?
In 2024 Medicare Part D data, Dr. Grenquist's most prescribed drugs by claims were Metoprolol Tartrate, Cefuroxime and Levofloxacin.
Has Dr. Mark Francis Grenquist received payments from drug or device companies?
CMS Open Payments shows $14 in general payments to Dr. Grenquist from 1 company from 2017 to 2017. The largest total came from GlaxoSmithKline, LLC.
How long has Dr. Mark Francis Grenquist been practicing?
Dr. Grenquist graduated from medical school in 2001, 25 years ago.
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