Active NPI 1548256977 Individual Practitioner Male Practitioner

Dr. Frederick Richard Stack , MD

Internal Medicine • Sioux City, IA

✓ Accepts Medicare Assignment

Professional Overview & Biography Verified Profile Summary

Dr. Frederick Stack, MD is a certified Internal Medicine practicing in Sioux City, IA. With approximately 35 years of clinical experience since graduating from University Of Nebraska College Of Medicine in 1991, Dr. Stack delivers high-quality medical care to the local community at 801 5TH ST.

Dr. Stack maintains professional affiliations with Pines Health Services, Eastern Maine Medical Center, Benefis Hospitals Inc and accepts Medicare assignment.

Frequently performed procedures and clinical services include subsequent hospital care with moderate levelof medical decision making, if using time, at least, hospital discharge day management, more than, initial hospital care with moderate level of medical decision making, if using time, at least. Full Medicare procedure pricing transparency rates and service volume details are listed on this profile.

Practice Location & Contact Primary Location

Practice Address

801 5th St

Sioux City, IA 511011326

Telephone 7122792010

Fax 7122792034

Associated Practice Facility / Clinic

🏢 Intensive Medical Services Of The Siouxland Facility NPI 1407846033

Medicare Profile & Education

Medical School

University Of Nebraska College Of Medicine

Graduation Year

1991

Medicare Assignment

✓ Accepts Assignment

Telehealth Flag

In-Person Only

Specialty Benchmarks & Practice Insights

Comparative analytics for Internal Medicine in Sioux City, IA

Senior Veteran Specialist (>20 Yrs)

Practitioner Clinical Experience

35 Yrs +11.7 yrs vs City Avg

City Avg: 23.3 Yrs

State Avg: 25.0 Yrs

Regional Practice Density

20 Specialists

Practicing in Sioux City, IA (907 Statewide)

Telehealth Adoption Rate

0.0% Regional Adoption

In-Person Office Visits Only

Medicare Pricing Discount

71.1% Avg Savings

Under CMS Medicare Fee Schedule vs Standard Submitted Charges

Clinical Seniority & Experience Comparison

Dr. Stack (35 Years) 35 Yrs

Sioux City Specialty Average (23.3 Years) 23.3 Yrs

Performed Procedures & Service Volume

Top Medicare Part B procedures performed by this practitioner

CMS Official Data (2024)

Reporting Year:

HCPCS Code & Description	Services	Patients	Submitted Charge	Medicare Allowed
99232 Subsequent hospital care with moderate levelof medical decision making, if using time, at least 35 minutes	420	161	$222.16	$76.41
99239 Hospital discharge day management, more than 30 minutes	122	121	$327.46	$110.85
99223 Initial hospital care with moderate level of medical decision making, if using time, at least 75 minutes	44	43	$749.64	$166.20
99222 Initial hospital care with straightforward or low-level medical decision making, if using time, at least 55 minutes	41	41	$364.93	$127.15
99233 Subsequent hospital care with moderate levelof medical decision making, if using time, at least 50 minutes	23	14	$391.22	$113.75

HCPCS Code & Description	Services	Patients	Submitted Charge	Medicare Allowed
99232 Subsequent hospital care with moderate levelof medical decision making, if using time, at least 35 minutes	609	189	$200.81	$76.49
99239 Hospital discharge day management, more than 30 minutes	131	129	$331.36	$110.48
99222 Initial hospital care with straightforward or low-level medical decision making, if using time, at least 55 minutes	45	44	$439.82	$126.13
99223 Initial hospital care with moderate level of medical decision making, if using time, at least 75 minutes	23	22	$725.25	$164.59
99233 Subsequent hospital care with moderate levelof medical decision making, if using time, at least 50 minutes	14	12	$248.43	$114.24

HCPCS Code & Description	Services	Patients	Submitted Charge	Medicare Allowed
99233 Subsequent hospital care with moderate levelof medical decision making, if using time, at least 50 minutes	258	84	$170.40	$96.13
99232 Subsequent hospital care with moderate levelof medical decision making, if using time, at least 35 minutes	95	47	$118.37	$67.13
99239 Hospital discharge day management, more than 30 minutes	45	44	$179.60	$99.20
99222 Initial hospital care with straightforward or low-level medical decision making, if using time, at least 55 minutes	37	37	$265.76	$131.56
99217 Hospital observation care on day of discharge	29	29	$122.93	$67.38
99238 Hospital discharge day management, 30 minutes or less	28	28	$121.21	$67.73
99223 Initial hospital care with moderate level of medical decision making, if using time, at least 75 minutes	25	25	$335.00	$186.18
99220 Hospital observation care, typically 70 minutes	19	19	$307.00	$168.13
99219 Hospital observation care, typically 50 minutes	17	17	$267.59	$128.95

HCPCS Code & Description	Services	Patients	Submitted Charge	Medicare Allowed
99233 Subsequent hospital care with moderate levelof medical decision making, if using time, at least 50 minutes	165	52	$208.94	$101.32
99239 Hospital discharge day management, more than 30 minutes	38	37	$222.51	$104.79
99232 Subsequent hospital care with moderate levelof medical decision making, if using time, at least 35 minutes	31	18	$135.55	$69.85
99222 Initial hospital care with straightforward or low-level medical decision making, if using time, at least 55 minutes	26	26	$277.28	$133.88
99223 Initial hospital care with moderate level of medical decision making, if using time, at least 75 minutes	26	26	$389.47	$196.80
99219 Hospital observation care, typically 50 minutes	12	12	$287.99	$132.97

HCPCS Code & Description	Services	Patients	Submitted Charge	Medicare Allowed
99232 Subsequent hospital care with moderate levelof medical decision making, if using time, at least 35 minutes	66	31	$307.73	$72.83
99233 Subsequent hospital care with moderate levelof medical decision making, if using time, at least 50 minutes	49	31	$746.45	$104.06
99223 Initial hospital care with moderate level of medical decision making, if using time, at least 75 minutes	42	42	$1252.33	$192.89
99291 Critical care, first 30-74 minutes	25	15	$1767.84	$221.51
99238 Hospital discharge day management, 30 minutes or less	15	15	$442.40	$73.04
99220 Hospital observation care, typically 70 minutes	15	14	$1188.20	$176.11
99222 Initial hospital care with straightforward or low-level medical decision making, if using time, at least 55 minutes	12	12	$814.75	$138.83

HCPCS Code & Description	Services	Patients	Submitted Charge	Medicare Allowed
99213 Established patient office or other outpatient visit, typically 15 minutes	130	106	$182.90	$71.86
99223 Initial hospital care with moderate level of medical decision making, if using time, at least 75 minutes	99	97	$1267.00	$193.73
99220 Hospital observation care, typically 70 minutes	64	62	$1161.00	$177.95
36415 Insertion of needle into vein for collection of blood sample	38	35	$26.20	$2.94
80053 Blood test, comprehensive group of blood chemicals	31	30	$94.90	$11.51
99215 Established patient office or other outpatient visit with high level of medical decision making, if using time, 40 minutes or more	28	11	$222.60	$143.08
85027 Complete blood cell count (red cells, white blood cell, platelets), automated test	26	25	$58.00	$7.04
93005 Routine electrocardiogram (ecg) using at least 12 leads with tracing	23	23	$82.20	$8.03
99233 Subsequent hospital care with moderate levelof medical decision making, if using time, at least 50 minutes	19	17	$588.89	$100.32
99291 Critical care, first 30-74 minutes	16	16	$1400.00	$212.86
99214 Established patient office or other outpatient visit with moderate level of decision making, if using time, 30 minutes or more	12	12	$277.70	$105.41

HCPCS Code & Description	Services	Patients	Submitted Charge	Medicare Allowed
99222 Initial hospital care with straightforward or low-level medical decision making, if using time, at least 55 minutes	71	71	$342.65	$131.13
99219 Hospital observation care, typically 50 minutes	39	39	$342.00	$132.06
99291 Critical care, first 30-74 minutes	24	24	$558.50	$215.97
99233 Subsequent hospital care with moderate levelof medical decision making, if using time, at least 50 minutes	21	11	$175.00	$101.21
99223 Initial hospital care with moderate level of medical decision making, if using time, at least 75 minutes	14	14	$382.00	$196.88

HCPCS Code & Description	Services	Patients	Submitted Charge	Medicare Allowed
99233 Subsequent hospital care with moderate levelof medical decision making, if using time, at least 50 minutes	521	213	$175.00	$98.44
99239 Hospital discharge day management, more than 30 minutes	229	188	$180.00	$101.42
99223 Initial hospital care with moderate level of medical decision making, if using time, at least 75 minutes	221	185	$338.24	$191.40
99291 Critical care, first 30-74 minutes	183	73	$488.70	$207.79
99220 Hospital observation care, typically 70 minutes	69	66	$288.99	$173.64
99217 Hospital observation care on day of discharge	65	61	$125.00	$68.00
99215 Established patient office or other outpatient visit with high level of medical decision making, if using time, 40 minutes or more	53	16	$215.12	$138.61
99292 Critical care, each additional 30 minutes	52	45	$218.00	$104.00
99232 Subsequent hospital care with moderate levelof medical decision making, if using time, at least 35 minutes	34	16	$122.00	$68.08
99222 Initial hospital care with straightforward or low-level medical decision making, if using time, at least 55 minutes	22	22	$275.68	$129.99
99226 Subsequent observation care, typically 35 minutes per day	17	14	$140.00	$99.09
99219 Hospital observation care, typically 50 minutes	13	13	$308.08	$129.66
99236 Initial hospital care with same-day admission and discharge with high level of medical decision making, per day, if using time, at least 85 minutes	12	12	$391.00	$205.46

Medical Specialties & State Licenses

CMS Verified: 2026-01-28

Internal Medicine Primary Specialty

NUCC Taxonomy Code: 207R00000X

State License IA MD-46368

A physician who provides long-term, comprehensive care in the office and the hospital, managing both common and complex illness of adolescents, adults and the elderly. Internists are trained in the diagnosis and treatment of cancer, infections and diseases affecting the heart, blood, kidneys, joints and digestive, respiratory and vascular systems. They are also trained in the essentials of primary care internal medicine, which incorporates an understanding of disease prevention, wellness, substance abuse, mental health and effective treatment of common problems of the eyes, ears, skin, nervous system and reproductive organs.

Internal Medicine

NUCC Taxonomy Code: 207R00000X

State License MT 91977

Specialist

NUCC Taxonomy Code: 174400000X

State License AZ 24459

An individual educated and trained in an applied knowledge discipline used in the performance of work at a level requiring knowledge and skills beyond or apart from that provided by a general education or liberal arts degree.

Additional State Medicaid & Healthcare Payer Identifiers

Medicaid State Provider ID

436693002 (AZ)

Commercial Insurance / Payer ID Blue Cross Bluee Shield

AZ0866740 (AZ)

Commercial Insurance / Payer ID Medicare Railroad

110208816 (AZ)

Hospital & Practice Group Affiliations

Pines Health Services

163 Van Buren Rd, Caribou, ME 047363567

Phone: 2074986921

Benefis Hospitals Inc

1101 26th St S, Great Falls, MT 594055161

Phone: 4064555000

Eastern Maine Medical Center

489 State St, Bangor, ME 044016616

Phone: 2079737000

Banner-University Medical Group

1625 N Campbell Ave, Tucson, AZ 857194330

Phone: 5206940111

Secondary Practice Locations

1821 N Trekell Rd, Suite 6

Casa Grande, AZ 852221705

Phone: 5204211122

1 Medical Center Dr

Biddeford, ME 040059422

Phone: 2072837937

1101 26th St S

Great Falls, MT 594055161

Phone: 4064554694

Practice Associates & Co-Workers

Healthcare professionals and specialists practicing at this location or sharing practice phone/fax

40 Associated Practitioners

Mark Davis , CNP

Nurse Practitioner

NPI 1053705871

Certified Nurse Practitioner

Ginger Hamilton , FNP

Nurse Practitioner

NPI 1063957843

Family Nurse Practitioner

Dr. Peter Anderson , MD

Internal Medicine

NPI 1114967858

Doctor of Medicine (M.D.)

Alex Schroeder

Nurse Anesthetist, Certified Registered

NPI 1124586250

Heather Kreber , MSPAS, PA-C

Physician Assistant - Medical

NPI 1184949471

MSPAS, Physician Assistant (Certified)

Dr. Olusola Ogundipe , MD

Internal Medicine - Infectious Disease

NPI 1194258558

Doctor of Medicine (M.D.)

Career & Practice History Timeline

Chronological log of verified NPI updates, location relocations, credentials, and registry changes

9 Historical Events

🎓

Medical Taxonomy / Specialty Registered (Primary Specialty) January 28, 2026

Internal Medicine (License #91977 in MT)

📍

Updated Business Mailing Address July 10, 2023

Registered at 6909 EAST RAY ROAD #15-114, CHANDLER, AZ 85226 (Tel: 5204211122)

📍

Updated Practice Location August 16, 2019

Registered at 801 5TH ST, SIOUX CITY, IA 511011326 (Tel: 7122792010)

✅

NPI Profile Active October 18, 2007

NPI status registered as active in NPPES database

📍

Updated Practice Location October 18, 2007

Registered at 1821 N TREKELL RD, SUITE 6, CASA GRANDE, AZ 852221705 (Tel: 5204211122)

📍

Updated Business Mailing Address October 18, 2007

Registered at 1821 N TREKELL RD, SUITE 6, CASA GRANDE, AZ 852221705 (Tel: 5204211122)

👤

Provider Name / Credentials Updated October 18, 2007

Recorded as FREDERICK STACK, MD

🎓

Medical Taxonomy / Specialty Registered (Primary Specialty) October 18, 2007

Specialist (License #24459 in AZ)

🟢

Initial NPI Registration & Enumeration September 21, 2005

First registered as active Individual Practitioner in NPPES Database.

Patient & Community Reviews

Verified patient ratings, medical care experiences, and facility photos

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NPI Administrative Meta

NPI Number: 1548256977

Entity Type:

Individual Provider Physician, Nurse Practitioner, or Solo Healthcare Professional (Type 1 NPI)

Enumeration Date: September 21, 2005

Last Update: January 28, 2026

Sole Proprietor: Yes

Update or Correct Profile

Mailing Address

6909 East Ray Road #15-114

Chandler, AZ 85226

Phone: 5204211122

Public Domain Record This profile contains public domain information published by CMS and NPPES under the Freedom of Information Act (FOIA).

⚠️ Medical Disclaimer

This directory listing is for informational purposes only and does not constitute medical advice, diagnosis, or physician endorsement. If you are experiencing a medical emergency, please call 911 immediately.