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Dr. Gretchen S. Johns, MD

(Dr. Gretchen Johns, MD)

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Specializes in: Clinical Pathology

St. Louis University School of Medicine (1995)

Professional interests include: blood disorders, blood transfusion

4500 San Pablo Road S
Jacksonville, FL 32224

(904) 953-2000

Dr. Gretchen S. Johns, MD is a clinical pathologist in Jacksonville, FL specializing in clinical pathology. She graduated from St. Louis University School of Medicine in 1995 and has 31 years of experience. Dr. Gretchen S. Johns, MD is affiliated with Mayo Clinic and MAYO CLINIC JACKSONVILLE.

Office Locations

4500 San Pablo Road S
Jacksonville, FL 32224

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Jacksonville, FL

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Some issues Dr. Gretchen S. Johns, MD can help you with:

Blood Transfusion

Blood transfusions typically treat those who experience a substantial loss of blood from an injury or surgical procedure, or those who suffer from conditions that alter the blood supply or blood components. For example, a blood transfusion may contribute additional red blood cells to someone with anemia, a condition where the body does not produce enough red blood cells. Other conditions may include:

Hemophilia (blood clotting disorder)
Leukemia
Liver disease
Sickle cell disease (misshapen red blood cells)
Thrombocytopenia (lack of platelets)

When a patient has sufficient blood volume and lacks one or more components, a complete blood count (CBC) test can help determine if a patient requires a transfusion by measuring four blood components: red blood cells, white blood cells, platelets, and hemoglobin. If any of the patient's component counts is significantly below a standard range, the patient will likely need a blood transfusion. The complete blood count test uses a needle to extract a small amount of blood for testing.

Blood transfusion recipients should be tested for their blood type, which is one of four different types: type A, B, AB, or O. Patients with A, B, and O blood can only receive a blood donation matching their blood type or of O blood, which is known as the universal donor. Those with AB blood are considered "universal recipients"; they may receive A, B, AB, or O blood. Further complicating blood types is the presence or absence of the RhD antigen, adding a positive or negative modifier that should also be considered. Incompatible blood donations may cause transfusion sickness, such as a hemolytic reaction, where the body fights the donated red blood cells.

In certain emergency or trauma situations, medical teams often do not perform a complete blood count (CBC) test or blood type test. In those cases, patients are often given O negative blood, which is universally accepted. Some patients have their blood type on a medical card or bracelet, allowing emergency medical teams to issue compatible blood without testing.

Transfusions are performed by inserting a needle attached to an intravenous line (IV) into a vein in the body. This IV line is attached to a bag of blood that steadily dispenses blood into the patient's bloodstream. The type, volume, and components of donated blood depend on the patient's condition and needs. After the transfusion is complete, patients are generally permitted to resume normal activity, unless prohibited by a condition or injury. Some patients may experience bruising or soreness around the area that the needle was inserted.

At times, a second complete blood count test is performed to determine if the transfusion has brought patients' component counts to normal levels. Some patients may require multiple blood transfusions to reach a healthy blood volume and blood component count.

Once patients' blood volumes and components reach sufficient levels, they will generally begin to feel better. Patients of all ages, from newborn infants to elderly adults, can receive a blood transfusion.

Noteworthy Medicare Patient Procedures Performed by Dr. Gretchen S. Johns, MD in 2023

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

Top 5%

By Volume:

blood draw

creatinine blood test

fasting blood glucose test

lab tests

phlebotomy for lab tests

prothrombin time test

timed urine measurement

von Willebrand factor antigen test

By Affordability:

D-dimer test

factor VIII clotting activity test

partial thromboplastin time test

timed urine measurement

urine volume measurement

von Willebrand factor antigen test

von Willebrand factor tests

In 2023, among providers in related specialties within Florida, Dr. Gretchen S. Johns, MD performed more blood draw, creatinine blood test, fasting blood glucose test, lab tests, phlebotomy for lab tests, prothrombin time (PT) test, timed urine measurement, and von Willebrand factor antigen test procedures for Medicare patients than 95% of them and she also had a list price for D-dimer test, factor VIII clotting activity test, partial thromboplastin time (PTT) test, timed urine measurement, urine volume measurement, von Willebrand factor antigen test, and von Willebrand factor tests that was lower than the list prices billed to Medicare by 95% of them. Actual amounts paid by patients can vary widely depending on a number of factors, including insurance coverage. A lower list price, however, might mean lower fees when paying without insurance.

Medicare Procedure and Patient Information

2012 Medicare Procedure Volume

The top procedures that Dr. Gretchen S. Johns, MD treated as a clinical pathologist in Jacksonville, FL during 2012 were lab tests, pulmonary testing, blood draw and preventive care.

Volume of procedures performed by Dr. Gretchen S. Johns, MD for Medicare patients.

blood draw	196
cytology	121
diabetes management	19
gynecologic pathology	121
lab tests	3853
preventive care	160
pulmonary testing	334
thyroid function tests	70

Medicare Procedure and Patient Information

2013 Medicare Procedure Volume

The top procedures that Dr. Gretchen S. Johns, MD treated as a clinical pathologist in Jacksonville, FL during 2013 were lab tests, pulmonary testing, cytology and gynecologic pathology.

Volume of procedures performed by Dr. Gretchen S. Johns, MD for Medicare patients.

cytology	136
gynecologic pathology	136
lab tests	4222
preventive care	58
pulmonary testing	315

2013 Medicare Patient Data

Information about Medicare patients treated by Dr. Gretchen S. Johns, MD.

**Gender**
Male	1108
Female	1063

**Ethnicity**
Non-Hispanic White	1917
Black	139
Hispanic	65
Asian	19
Other	31
Native American	0

**Age**
From 65 to 74	986
From 75 to 84	648
85 and over	177
Less than 65	360

Conditions of Medicare patients treated by Dr. Gretchen S. Johns, MD in 2013

Hypertension	68
High Cholesterol	55
Stroke	5
Ischemic Heart Disease	48
Depression	22
Chronic Kidney Disease	34
Asthma	8
Osteoperosis	13
Atrial Fibrilation	15
Heart Failure	21
Chronic Obstructive Pulmonary Disease	21
Diabetes	36
Dementia	7
Cancer	17

Medicare Procedure and Patient Information

2014 Medicare Procedure Volume

The top procedures that Dr. Gretchen S. Johns, MD treated as a clinical pathologist in Jacksonville, FL during 2014 were lab tests, pulmonary testing, preventive care and cytology.

Volume of procedures performed by Dr. Gretchen S. Johns, MD for Medicare patients.

cytology	44
gynecologic pathology	44
lab tests	2063
preventive care	44
pulmonary testing	347

2014 Medicare Patient Data

Information about Medicare patients treated by Dr. Gretchen S. Johns, MD.

**Gender**
Male	726
Female	933

**Ethnicity**
Non-Hispanic White	1472
Black	94
Hispanic	48
Asian	0
Other	29
Native American	0

**Age**
From 65 to 74	694
From 75 to 84	524
85 and over	252
Less than 65	189

Conditions of Medicare patients treated by Dr. Gretchen S. Johns, MD in 2014

Hypertension	63
High Cholesterol	51
Stroke	5
Ischemic Heart Disease	46
Depression	17
Chronic Kidney Disease	27
Asthma	8
Osteoperosis	11
Atrial Fibrilation	39
Heart Failure	22
Chronic Obstructive Pulmonary Disease	21
Diabetes	32
Dementia	6
Cancer	17

Medicare Procedure and Patient Information

2015 Medicare Procedure Volume

The top procedures that Dr. Gretchen S. Johns, MD treated as a clinical pathologist in Jacksonville, FL during 2015 were lab tests, pulmonary testing, preventive care and cytology.

Volume of procedures performed by Dr. Gretchen S. Johns, MD for Medicare patients.

cytology	52
gynecologic pathology	52
lab tests	12763
preventive care	52
pulmonary testing	364

2015 Medicare Patient Data

Information about Medicare patients treated by Dr. Gretchen S. Johns, MD.

**Gender**
Male	2804
Female	2842

**Ethnicity**
Non-Hispanic White	5008
Black	362
Hispanic	128
Asian	0
Other	92
Native American	0

**Age**
From 65 to 74	2278
From 75 to 84	1812
85 and over	906
Less than 65	650

Conditions of Medicare patients treated by Dr. Gretchen S. Johns, MD in 2015

Hypertension	65
High Cholesterol	54
Stroke	7
Ischemic Heart Disease	48
Depression	18
Chronic Kidney Disease	31
Asthma	11
Osteoperosis	8
Atrial Fibrilation	40
Heart Failure	25
Chronic Obstructive Pulmonary Disease	18
Diabetes	31
Dementia	7
Cancer	17

Medicare Procedure and Patient Information

2016 Medicare Procedure Volume

The top procedures that Dr. Gretchen S. Johns, MD treated as a clinical pathologist in Jacksonville, FL during 2016 were blood draw, lab tests and pulmonary testing.

Volume of procedures performed by Dr. Gretchen S. Johns, MD for Medicare patients.

blood draw	16222
lab tests	14065
pulmonary testing	332

2016 Medicare Patient Data

Information about Medicare patients treated by Dr. Gretchen S. Johns, MD.

**Gender**
Male	4782
Female	5203

**Ethnicity**
Non-Hispanic White	8652
Black	741
Hispanic	243
Asian	0
Other	208
Native American	0

**Age**
From 65 to 74	4304
From 75 to 84	3024
85 and over	1349
Less than 65	1308

Conditions of Medicare patients treated by Dr. Gretchen S. Johns, MD in 2016

Hypertension	64
High Cholesterol	50
Stroke	6
Ischemic Heart Disease	40
Depression	18
Chronic Kidney Disease	34
Asthma	13
Osteoperosis	9
Atrial Fibrilation	17
Heart Failure	19
Chronic Obstructive Pulmonary Disease	13
Diabetes	30
Dementia	9
Cancer	12

Medicare Procedure and Patient Information

2017 Medicare Procedure Volume

The top procedures that Dr. Gretchen S. Johns, MD treated as a clinical pathologist in Jacksonville, FL during 2017 were blood draw, lab tests and pulmonary testing.

Volume of procedures performed by Dr. Gretchen S. Johns, MD for Medicare patients.

blood draw	19429
lab tests	10508
pulmonary testing	342

2017 Medicare Patient Data

Information about Medicare patients treated by Dr. Gretchen S. Johns, MD.

**Gender**
Male	5012
Female	5370

**Ethnicity**
Non-Hispanic White	8876
Black	813
Hispanic	268
Asian	143
Other	268
Native American	14

**Age**
From 65 to 74	4518
From 75 to 84	3125
85 and over	1306
Less than 65	1433

Conditions of Medicare patients treated by Dr. Gretchen S. Johns, MD in 2017

Hypertension	66
High Cholesterol	51
Stroke	6
Ischemic Heart Disease	40
Depression	21
Chronic Kidney Disease	37
Asthma	5
Osteoperosis	9
Atrial Fibrilation	16
Heart Failure	19
Chronic Obstructive Pulmonary Disease	13
Diabetes	31
Dementia	10
Cancer	11

Medicare Procedure and Patient Information

2018 Medicare Procedure Volume

The top procedures that Dr. Gretchen S. Johns, MD treated as a clinical pathologist in Jacksonville, FL during 2018 were blood draw, lab tests, pulmonary testing and thyroid function tests.

Volume of procedures performed by Dr. Gretchen S. Johns, MD for Medicare patients.

blood draw	28327
cytology	14
gynecologic pathology	14
lab tests	12090
preventive care	72
pulmonary testing	280
thyroid function tests	86

2018 Medicare Patient Data

Information about Medicare patients treated by Dr. Gretchen S. Johns, MD.

**Gender**
Male	7482
Female	7377

**Ethnicity**
Non-Hispanic White	12666
Black	1110
Hispanic	462
Asian	202
Other	404
Native American	15

**Age**
From 65 to 74	7001
From 75 to 84	4479
85 and over	1586
Less than 65	1793

Conditions of Medicare patients treated by Dr. Gretchen S. Johns, MD in 2018

Hypertension	67
High Cholesterol	56
Stroke	6
Ischemic Heart Disease	41
Depression	20
Chronic Kidney Disease	37
Asthma	6
Osteoperosis	9
Atrial Fibrilation	15
Heart Failure	19
Chronic Obstructive Pulmonary Disease	13
Diabetes	30
Dementia	9
Cancer	16

Medicare Procedure and Patient Information

2019 Medicare Procedure Volume

The top procedures that Dr. Gretchen S. Johns, MD treated as a clinical pathologist in Jacksonville, FL during 2019 were blood draw, lab tests, preventive care and thyroid function tests.

Volume of procedures performed by Dr. Gretchen S. Johns, MD for Medicare patients.

blood draw	65252
cytology	87
gynecologic pathology	87
lab tests	26492
preventive care	546
thyroid function tests	491

2019 Medicare Patient Data

Information about Medicare patients treated by Dr. Gretchen S. Johns, MD.

**Gender**
Male	12731
Female	12431

**Ethnicity**
Non-Hispanic White	21554
Black	1742
Hispanic	747
Asian	330
Other	765
Native American	24

**Age**
From 65 to 74	12238
From 75 to 84	7922
85 and over	2375
Less than 65	2627

Conditions of Medicare patients treated by Dr. Gretchen S. Johns, MD in 2019

Hypertension	68
High Cholesterol	61
Stroke	6
Ischemic Heart Disease	40
Depression	21
Chronic Kidney Disease	39
Asthma	7
Osteoperosis	11
Atrial Fibrilation	15
Heart Failure	20
Chronic Obstructive Pulmonary Disease	13
Diabetes	28
Dementia	9
Cancer	18

Medicare Procedure and Patient Information

2020 Medicare Procedure Volume

The top procedures that Dr. Gretchen S. Johns, MD treated as a clinical pathologist in Jacksonville, FL during 2020 were blood draw, lab tests, preventive care and thyroid function tests.

Volume of procedures performed by Dr. Gretchen S. Johns, MD for Medicare patients.

blood draw	67692
cytology	54
gynecologic pathology	54
lab tests	24779
preventive care	556
thyroid function tests	490

2020 Medicare Patient Data

Information about Medicare patients treated by Dr. Gretchen S. Johns, MD.

**Gender**
Male	12908
Female	12443

**Ethnicity**
Non-Hispanic White	21595
Black	1813
Hispanic	762
Asian	329
Other	830
Native American	22

**Age**
From 65 to 74	12481
From 75 to 84	7879
85 and over	2258
Less than 65	2733

Conditions of Medicare patients treated by Dr. Gretchen S. Johns, MD in 2020

Hypertension	66
High Cholesterol	61
Stroke	5
Ischemic Heart Disease	38
Depression	20
Chronic Kidney Disease	40
Asthma	6
Osteoperosis	10
Atrial Fibrilation	14
Heart Failure	19
Chronic Obstructive Pulmonary Disease	12
Diabetes	28
Dementia	9
Cancer	19

Medicare Procedure and Patient Information

2021 Medicare Procedure Volume

The top procedures that Dr. Gretchen S. Johns, MD treated as a clinical pathologist in Jacksonville, FL during 2021 were blood draw and lab tests.

Volume of procedures performed by Dr. Gretchen S. Johns, MD for Medicare patients.

blood draw	72398
lab tests	16978

2021 Medicare Patient Data

Information about Medicare patients treated by Dr. Gretchen S. Johns, MD.

**Gender**
Male	13357
Female	12694

**Ethnicity**
Non-Hispanic White	22147
Black	1769
Hispanic	825
Asian	388
Other	898
Native American	24

**Age**
From 65 to 74	12693
From 75 to 84	8580
85 and over	2271
Less than 65	2507

Conditions of Medicare patients treated by Dr. Gretchen S. Johns, MD in 2021

Hypertension	68
High Cholesterol	63
Stroke	5
Ischemic Heart Disease	38
Depression	20
Chronic Kidney Disease	41
Asthma	7
Osteoperosis	11
Atrial Fibrilation	14
Heart Failure	19
Chronic Obstructive Pulmonary Disease	12
Diabetes	28
Dementia	9
Cancer	19

Medicare Procedure and Patient Information

2022 Medicare Procedure Volume

The top procedures that Dr. Gretchen S. Johns, MD treated as a clinical pathologist in Jacksonville, FL during 2022 were blood draw, lab tests and preventive care.

Volume of procedures performed by Dr. Gretchen S. Johns, MD for Medicare patients.

blood draw	73829
lab tests	18008
preventive care	183

2022 Medicare Patient Data

Information about Medicare patients treated by Dr. Gretchen S. Johns, MD.

**Gender**
Male	13628
Female	13060

**Ethnicity**
Non-Hispanic White	22727
Black	1690
Hispanic	841
Asian	421
Other	988
Native American	21

**Age**
From 65 to 74	13098
From 75 to 84	9193
85 and over	2243
Less than 65	2154

Conditions of Medicare patients treated by Dr. Gretchen S. Johns, MD in 2022

Hypertension	75
High Cholesterol	75
Stroke	9
Ischemic Heart Disease	30
Depression	19
Chronic Kidney Disease	31
Asthma	10
Osteoperosis	17
Atrial Fibrilation	21
Heart Failure	17
Chronic Obstructive Pulmonary Disease	15
Diabetes	27
Dementia	5
Cancer	26

Medicare Procedure and Patient Information

Average Medicare Procedure Volume From 2012 - 2022

Volume of procedures performed by Dr. Gretchen S. Johns, MD for Medicare patients.

The highest averages for the top procedures that Dr. Gretchen S. Johns, MD treated as a clinical pathologist in Jacksonville, FL were blood draw, lab tests, pulmonary testing and thyroid function tests.

blood draw	42918
cytology	72
diabetes management	19
gynecologic pathology	72
lab tests	13256
preventive care	208
pulmonary testing	330
thyroid function tests	284

Average Medicare Patient Data From 2012 - 2022

Information about Medicare patients treated by Dr. Gretchen S. Johns, MD.

**Gender**
Male	6776
Female	6674

**Ethnicity**
Black / African American	933
Asian / Pacific Islander	166
Non-Hispanic White	11510
Hispanic	399
Native American / Alaskan Native	10
Other	410

**Age**
75 to 84	4289
85 and over	1338
Less than 65	1432
65 to 74	6390

Average of Total of Conditions of Medicare patients treated by Dr. Gretchen S. Johns, MD From 2012 - 2022

The highest averages of the most common conditions of Medicare patients that Dr. Gretchen S. Johns, MD treated were hypertension, high cholesterol, ischemic heart disease and chronic kidney disease.

Hypertension	60
High Cholesterol	52
Stroke	5
Ischemic Heart Disease	37
Depression	17
Chronic Kidney Disease	31
Asthma	7
Osteoporosis	9
Heart Failure	18
Chronic Obstructive Pulmonary Disease	13
Diabetes	27
Atrial Fibrillation	18
Cancer	15
Dementia	7

Education & Training

Dr. Gretchen S. Johns, MD graduated from St. Louis University School of Medicine in 1995. She completed residency at University of Florida Health Science Center and Affiliated Hospitals. She is certified by the Clinical Pathology American Board of Pathology and has a state license in Florida.

Medical School: St. Louis University School of Medicine (1995)

Residency: University of Florida Health Science Center and Affiliated Hospitals (1996)

Board Certification: Clinical Pathology American Board of Pathology (2002)

Licensed In: Florida

Affiliations & Hospitals

Dr. Gretchen S. Johns, MD is associated with these hospitals and organizations:

Mayo Clinic

MAYO CLINIC JACKSONVILLE

Ratings & Reviews

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General Payments

These charts describe general payments received by Dr. Gretchen S. Johns, MD. Doctors may receive payments for a number of reasons, including meal compensation, travel compensation, and consulting.

**Payments by Company**
BioFire Diagnostics, LLC	$40 Film Array $40
Boehringer Ingelheim Pharmaceuticals, Inc.	$39 TRADJENTA $39
Werfen USA LLC	$33 $33

**Types of Payments**
Compensation for services other than consulting, including serving as faculty or as a speaker at a venue other than a continuing education program	$40
Education	$39
Food and Beverage	$33

Biography

Dr. Gretchen Johns is a clinical pathology specialist. Dr. Johns graduated from St. Louis University School of Medicine and then she performed her residency at a hospital affiliated with St. Louis University (SLU) and a hospital affiliated with the University of Florida Health Science Center. Her clinical interests include blood transfusion and blood disorders. Her distinctions include: Caring Physician Award Nominee - St. Louis University Hospital; Department of Pathology Faculty of the Year Award - St. Louis University Hospital; and Robert H. Felix Dean's Staff Award - Saint Louis University School of Medicine. Dr. Johns is affiliated with Mayo Clinic.