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Home > MO Providers > Molecular Genetic Pathologists

Dr. John D. Pfeifer, MD, PhD

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Specializes in: Molecular Genetic Pathology and Anatomic Pathology

University of California, San Diego (UCSD), School of Medicine (1988)

Professional interests include: gynecologic pathology

1 Barnes Jewish Hospital Plaza
Saint Louis, MO 63110

(314) 362-5641

Dr. John D. Pfeifer, MD, PhD is a molecular genetic pathologist in Saint Louis, MO specializing in molecular genetic pathology and anatomic pathology. He graduated from University of California, San Diego (UCSD), School of Medicine in 1988 and has 38 years of experience. Dr. John D. Pfeifer, MD, PhD is affiliated with WashU Medicine.

Office Locations

1 Barnes Jewish Hospital Plaza
Saint Louis, MO 63110

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In The News

“Dr. John Pfeifer, vice chairman for clinical affairs in the pathology and immunology department at Washington University School of Medicine, has done extensive research on biopsy mix-up results and...”—"Doctor said it was cancer, it wasn't, but news came too late", The Washington Times, February 2018

“Dr. John Pfeifer, vice chairman for clinical affairs in the pathology and immunology department at Washington University School of Medicine in St. Louis, who has studied the problem, is not quite...”—"The Lab Says It's Cancer. But Sometimes the Lab Is Wrong. (Published 2017)", New York Times, June 2017

Noteworthy Medicare Patient Procedures Performed by Dr. John D. Pfeifer, MD, PhD in 2024

Click on any procedure below to see further details on volume and pricing among Medicare patients.

Top 5%

By Volume:

immunohistochemistry test

intraoperative pathology consultation

In 2024, Dr. John D. Pfeifer, MD, PhD performed more immunohistochemistry (IHC) test, and intraoperative pathology consultation procedures for Medicare patients than 95% of providers in related specialties within Missouri.

Medicare Procedure and Patient Information

2012 Medicare Procedure Volume

The top procedures that Dr. John D. Pfeifer, MD, PhD treated as a molecular genetic pathologist in Saint Louis, MO during 2012 were lab tests and consultation.

Volume of procedures performed by Dr. John D. Pfeifer, MD, PhD for Medicare patients.

consultation	18
lab tests	41

Medicare Procedure and Patient Information

2013 Medicare Procedure Volume

The top procedures that Dr. John D. Pfeifer, MD, PhD treated as a molecular genetic pathologist in Saint Louis, MO during 2013 were lab tests and consultation.

Volume of procedures performed by Dr. John D. Pfeifer, MD, PhD for Medicare patients.

consultation	18
lab tests	59

2013 Medicare Patient Data

Information about Medicare patients treated by Dr. John D. Pfeifer, MD, PhD.

**Gender**
Male	19
Female	110

**Ethnicity**
Non-Hispanic White	88
Black	0
Hispanic	0
Asian	0
Other	0
Native American	0

**Age**
From 65 to 74	54
From 75 to 84	0
85 and over	0
Less than 65	51

Conditions of Medicare patients treated by Dr. John D. Pfeifer, MD, PhD in 2013

Hypertension	75
High Cholesterol	59
Stroke	0
Ischemic Heart Disease	39
Depression	32
Chronic Kidney Disease	40
Asthma	12
Osteoperosis	9
Atrial Fibrilation	16
Heart Failure	28
Chronic Obstructive Pulmonary Disease	12
Diabetes	36
Dementia	0
Cancer	15

Medicare Procedure and Patient Information

2014 Medicare Procedure Volume

The top procedures that Dr. John D. Pfeifer, MD, PhD treated as a molecular genetic pathologist in Saint Louis, MO during 2014 were lab tests.

Volume of procedures performed by Dr. John D. Pfeifer, MD, PhD for Medicare patients.

lab tests	38

2014 Medicare Patient Data

Information about Medicare patients treated by Dr. John D. Pfeifer, MD, PhD.

**Gender**
Male	24
Female	108

**Ethnicity**
Non-Hispanic White	90
Black	0
Hispanic	0
Asian	0
Other	0
Native American	0

**Age**
From 65 to 74	46
From 75 to 84	0
85 and over	0
Less than 65	59

Conditions of Medicare patients treated by Dr. John D. Pfeifer, MD, PhD in 2014

Hypertension	73
High Cholesterol	55
Stroke	0
Ischemic Heart Disease	42
Depression	30
Chronic Kidney Disease	37
Asthma	14
Osteoperosis	0
Atrial Fibrilation	17
Heart Failure	36
Chronic Obstructive Pulmonary Disease	14
Diabetes	38
Dementia	0
Cancer	18

Medicare Procedure and Patient Information

2015 Medicare Procedure Volume

The top procedures that Dr. John D. Pfeifer, MD, PhD treated as a molecular genetic pathologist in Saint Louis, MO during 2015 were lab tests.

Volume of procedures performed by Dr. John D. Pfeifer, MD, PhD for Medicare patients.

lab tests	31

2015 Medicare Patient Data

Information about Medicare patients treated by Dr. John D. Pfeifer, MD, PhD.

**Gender**
Male	28
Female	210

**Ethnicity**
Non-Hispanic White	166
Black	0
Hispanic	0
Asian	0
Other	0
Native American	0

**Age**
From 65 to 74	94
From 75 to 84	0
85 and over	0
Less than 65	108

Conditions of Medicare patients treated by Dr. John D. Pfeifer, MD, PhD in 2015

Hypertension	70
High Cholesterol	53
Stroke	0
Ischemic Heart Disease	27
Depression	39
Chronic Kidney Disease	42
Asthma	12
Osteoperosis	0
Atrial Fibrilation	13
Heart Failure	20
Chronic Obstructive Pulmonary Disease	13
Diabetes	39
Dementia	0
Cancer	16

Medicare Procedure and Patient Information

2016 Medicare Procedure Volume

The top procedures that Dr. John D. Pfeifer, MD, PhD treated as a molecular genetic pathologist in Saint Louis, MO during 2016 were lab tests.

Volume of procedures performed by Dr. John D. Pfeifer, MD, PhD for Medicare patients.

lab tests	20

2016 Medicare Patient Data

Information about Medicare patients treated by Dr. John D. Pfeifer, MD, PhD.

**Gender**
Male	16
Female	77

**Ethnicity**
Non-Hispanic White	70
Black	0
Hispanic	0
Asian	0
Other	0
Native American	0

**Age**
From 65 to 74	43
From 75 to 84	0
85 and over	0
Less than 65	31

Conditions of Medicare patients treated by Dr. John D. Pfeifer, MD, PhD in 2016

Hypertension	75
High Cholesterol	63
Stroke	0
Ischemic Heart Disease	43
Depression	49
Chronic Kidney Disease	57
Asthma	22
Osteoperosis	0
Atrial Fibrilation	20
Heart Failure	32
Chronic Obstructive Pulmonary Disease	12
Diabetes	47
Dementia	12
Cancer	16

Medicare Procedure and Patient Information

2017 Medicare Procedure Volume

The top procedures that Dr. John D. Pfeifer, MD, PhD treated as a molecular genetic pathologist in Saint Louis, MO during 2017 were lab tests.

Volume of procedures performed by Dr. John D. Pfeifer, MD, PhD for Medicare patients.

lab tests	27

2017 Medicare Patient Data

Information about Medicare patients treated by Dr. John D. Pfeifer, MD, PhD.

**Ethnicity**
Non-Hispanic White	58
Black	0
Hispanic	0
Asian	0
Other	0
Native American	0

**Age**
From 65 to 74	28
From 75 to 84	0
85 and over	0
Less than 65	31

Conditions of Medicare patients treated by Dr. John D. Pfeifer, MD, PhD in 2017

Hypertension	72
High Cholesterol	48
Stroke	0
Ischemic Heart Disease	39
Depression	37
Chronic Kidney Disease	49
Asthma	14
Osteoperosis	0
Atrial Fibrilation	19
Heart Failure	30
Chronic Obstructive Pulmonary Disease	14
Diabetes	37
Dementia	0
Cancer	14

Medicare Procedure and Patient Information

2018 Medicare Procedure Volume

The top procedures that Dr. John D. Pfeifer, MD, PhD treated as a molecular genetic pathologist in Saint Louis, MO during 2018 were lab tests.

Volume of procedures performed by Dr. John D. Pfeifer, MD, PhD for Medicare patients.

lab tests	36

2018 Medicare Patient Data

Information about Medicare patients treated by Dr. John D. Pfeifer, MD, PhD.

**Ethnicity**
Non-Hispanic White	77
Black	0
Hispanic	0
Asian	0
Other	0
Native American	0

**Age**
From 65 to 74	50
From 75 to 84	0
85 and over	0
Less than 65	29

Conditions of Medicare patients treated by Dr. John D. Pfeifer, MD, PhD in 2018

Hypertension	69
High Cholesterol	51
Stroke	0
Ischemic Heart Disease	20
Depression	29
Chronic Kidney Disease	27
Asthma	13
Osteoperosis	0
Atrial Fibrilation	0
Heart Failure	13
Chronic Obstructive Pulmonary Disease	11
Diabetes	30
Dementia	0
Cancer	18

Medicare Procedure and Patient Information

2019 Medicare Procedure Volume

The top procedures that Dr. John D. Pfeifer, MD, PhD treated as a molecular genetic pathologist in Saint Louis, MO during 2019 were lab tests.

Volume of procedures performed by Dr. John D. Pfeifer, MD, PhD for Medicare patients.

lab tests	36

2019 Medicare Patient Data

Information about Medicare patients treated by Dr. John D. Pfeifer, MD, PhD.

**Gender**
Male	0
Female	85

**Ethnicity**
Non-Hispanic White	56
Black	0
Hispanic	0
Asian	0
Other	0
Native American	0

**Age**
From 65 to 74	35
From 75 to 84	0
85 and over	0
Less than 65	30

Conditions of Medicare patients treated by Dr. John D. Pfeifer, MD, PhD in 2019

Hypertension	72
High Cholesterol	59
Stroke	0
Ischemic Heart Disease	22
Depression	33
Chronic Kidney Disease	44
Asthma	13
Osteoperosis	0
Atrial Fibrilation	0
Heart Failure	20
Chronic Obstructive Pulmonary Disease	0
Diabetes	41
Dementia	0
Cancer	15

Medicare Procedure and Patient Information

2020 Medicare Procedure Volume

The top procedures that Dr. John D. Pfeifer, MD, PhD treated as a molecular genetic pathologist in Saint Louis, MO during 2020 were lab tests and consultation.

Volume of procedures performed by Dr. John D. Pfeifer, MD, PhD for Medicare patients.

consultation	70
lab tests	124

2020 Medicare Patient Data

Information about Medicare patients treated by Dr. John D. Pfeifer, MD, PhD.

**Gender**
Male	14
Female	229

**Ethnicity**
Non-Hispanic White	188
Black	0
Hispanic	0
Asian	0
Other	0
Native American	0

**Age**
From 65 to 74	120
From 75 to 84	0
85 and over	0
Less than 65	75

Conditions of Medicare patients treated by Dr. John D. Pfeifer, MD, PhD in 2020

Hypertension	67
High Cholesterol	51
Stroke	0
Ischemic Heart Disease	29
Depression	36
Chronic Kidney Disease	39
Asthma	9
Osteoperosis	10
Atrial Fibrilation	9
Heart Failure	18
Chronic Obstructive Pulmonary Disease	16
Diabetes	28
Dementia	7
Cancer	18

Medicare Procedure and Patient Information

2021 Medicare Procedure Volume

The top procedures that Dr. John D. Pfeifer, MD, PhD treated as a molecular genetic pathologist in Saint Louis, MO during 2021 were lab tests and consultation.

Volume of procedures performed by Dr. John D. Pfeifer, MD, PhD for Medicare patients.

consultation	114
lab tests	208

2021 Medicare Patient Data

Information about Medicare patients treated by Dr. John D. Pfeifer, MD, PhD.

**Gender**
Male	16
Female	232

**Ethnicity**
Non-Hispanic White	198
Black	0
Hispanic	0
Asian	0
Other	0
Native American	0

**Age**
From 65 to 74	126
From 75 to 84	61
85 and over	0
Less than 65	0

Conditions of Medicare patients treated by Dr. John D. Pfeifer, MD, PhD in 2021

Hypertension	74
High Cholesterol	60
Stroke	0
Ischemic Heart Disease	30
Depression	27
Chronic Kidney Disease	46
Asthma	14
Osteoperosis	12
Atrial Fibrilation	9
Heart Failure	20
Chronic Obstructive Pulmonary Disease	15
Diabetes	34
Dementia	11
Cancer	19

Medicare Procedure and Patient Information

2022 Medicare Procedure Volume

The top procedures that Dr. John D. Pfeifer, MD, PhD treated as a molecular genetic pathologist in Saint Louis, MO during 2022 were lab tests and consultation.

Volume of procedures performed by Dr. John D. Pfeifer, MD, PhD for Medicare patients.

consultation	87
lab tests	286

2022 Medicare Patient Data

Information about Medicare patients treated by Dr. John D. Pfeifer, MD, PhD.

**Gender**
Male	20
Female	206

**Ethnicity**
Non-Hispanic White	171
Black	0
Hispanic	0
Asian	0
Other	0
Native American	0

**Age**
From 65 to 74	129
From 75 to 84	44
85 and over	0
Less than 65	0

Conditions of Medicare patients treated by Dr. John D. Pfeifer, MD, PhD in 2022

Hypertension	75
High Cholesterol	64
Stroke	8
Ischemic Heart Disease	15
Depression	28
Chronic Kidney Disease	22
Asthma	12
Osteoperosis	15
Atrial Fibrilation	14
Heart Failure	15
Chronic Obstructive Pulmonary Disease	15
Diabetes	31
Dementia	0
Cancer	40

Medicare Procedure and Patient Information

2023 Medicare Procedure Volume

The top procedures that Dr. John D. Pfeifer, MD, PhD treated as a molecular genetic pathologist in Saint Louis, MO during 2023 were lab tests and consultation.

Volume of procedures performed by Dr. John D. Pfeifer, MD, PhD for Medicare patients.

consultation	62
lab tests	279

2023 Medicare Patient Data

Information about Medicare patients treated by Dr. John D. Pfeifer, MD, PhD.

**Gender**
Male	13
Female	242

**Ethnicity**
Non-Hispanic White	210
Black	34
Hispanic	0
Asian	0
Other	0
Native American	0

**Age**
From 65 to 74	128
From 75 to 84	67
85 and over	13
Less than 65	47

Conditions of Medicare patients treated by Dr. John D. Pfeifer, MD, PhD in 2023

Hypertension	75
High Cholesterol	68
Stroke	6
Ischemic Heart Disease	16
Depression	27
Chronic Kidney Disease	26
Asthma	15
Osteoperosis	15
Atrial Fibrilation	15
Heart Failure	15
Chronic Obstructive Pulmonary Disease	14
Diabetes	34
Dementia	0
Cancer	40

Medicare Procedure and Patient Information

2024 Medicare Procedure Volume

The top procedures that Dr. John D. Pfeifer, MD, PhD treated as a molecular genetic pathologist in Saint Louis, MO during 2024 were lab tests and consultation.

Volume of procedures performed by Dr. John D. Pfeifer, MD, PhD for Medicare patients.

consultation	98
lab tests	291

2024 Medicare Patient Data

Information about Medicare patients treated by Dr. John D. Pfeifer, MD, PhD.

**Gender**
Male	18
Female	254

**Ethnicity**
Non-Hispanic White	221
Black	40
Hispanic	0
Asian	0
Other	0
Native American	0

**Age**
From 65 to 74	143
From 75 to 84	71
85 and over	0
Less than 65	0

Conditions of Medicare patients treated by Dr. John D. Pfeifer, MD, PhD in 2024

Hypertension	74
High Cholesterol	66
Stroke	6
Ischemic Heart Disease	25
Depression	28
Chronic Kidney Disease	20
Asthma	15
Osteoperosis	11
Atrial Fibrilation	13
Heart Failure	15
Chronic Obstructive Pulmonary Disease	15
Diabetes	33
Dementia	0
Cancer	40

Medicare Procedure and Patient Information

Average Medicare Procedure Volume From 2012 - 2024

Volume of procedures performed by Dr. John D. Pfeifer, MD, PhD for Medicare patients.

The highest averages for the top procedures that Dr. John D. Pfeifer, MD, PhD treated as a molecular genetic pathologist in Saint Louis, MO were lab tests and consultation.

consultation	66
lab tests	113

Average Medicare Patient Data From 2012 - 2024

Information about Medicare patients treated by Dr. John D. Pfeifer, MD, PhD.

**Gender**
Male	12
Female	134

**Ethnicity**
Black / African American	5
Asian / Pacific Islander	0
Non-Hispanic White	122
Native American / Alaskan Native	0
Hispanic	0
Other	0

**Age**
75 to 84	18
85 and over	1
Less than 65	35
65 to 74	76

Average of Total of Conditions of Medicare patients treated by Dr. John D. Pfeifer, MD, PhD From 2012 - 2024

The highest averages of the most common conditions of Medicare patients that Dr. John D. Pfeifer, MD, PhD treated were hypertension, high cholesterol, chronic kidney disease and diabetes.

Hypertension	67
High Cholesterol	53
Stroke	1
Ischemic Heart Disease	26
Depression	30
Chronic Kidney Disease	34
Asthma	12
Osteoporosis	5
Heart Failure	20
Chronic Obstructive Pulmonary Disease	11
Diabetes	32
Atrial Fibrillation	11
Cancer	20
Dementia	2

Education & Training

Dr. John D. Pfeifer, MD, PhD graduated from University of California, San Diego (UCSD), School of Medicine in 1988. He completed residency at Barnes-Jewish Hospital. He is certified by the Board Certification: Molecular Genetic Pathology and has a state license in Missouri.

Medical School: University of California, San Diego (UCSD), School of Medicine (1988)

Residency: Barnes-Jewish Hospital (1992)

Board Certification: Board Certification: Molecular Genetic Pathology

Licensed In: Missouri

Affiliations & Hospitals

Dr. John D. Pfeifer, MD, PhD is associated with these hospitals and organizations:

WashU Medicine

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General Payments

These charts describe general payments received by Dr. John D. Pfeifer, MD, PhD. Doctors may receive payments for a number of reasons, including meal compensation, travel compensation, and consulting.

**Payments by Company**
Novartis Pharmaceuticals Corporation	$6,171 NON_BRAND $6,171
Ventana Medical Systems, Inc.	$3,091 VENTANA RESEARCH & DEVELOPMENT $3,091
QIAGEN SCIENCES LLC	$1,833 $1,833
GlaxoSmithKline, LLC.	$19 TRELEGY ELLIPTA $19

**Types of Payments**
Consulting Fee	$7,133
Travel and Lodging	$1,573
Compensation for services other than consulting, including serving as faculty or as a speaker at a venue other than a continuing education program	$1,500
Education	$464
Food and Beverage	$444

Biography

Dr. John Pfeifer practices anatomic pathology and molecular genetic pathology. Dr. Pfeifer is especially interested in gynecologic pathology. He is professionally affiliated with Barnes-Jewish West County Hospital, WashU Medicine, and Barnes-Jewish Hospital. He is a graduate of the University of California, San Diego (UCSD), School of Medicine.