Active NPI 1942213509 Individual Practitioner Male Practitioner

Dr. Gregory A. Johnson , MD

Internal Medicine • Somerville, MA

✓ Accepts Medicare Assignment

Professional Overview & Biography Verified Profile Summary

Dr. Gregory Johnson, MD is a certified Internal Medicine practicing in Somerville, MA. With approximately 33 years of clinical experience since graduating from Warren Alpert Medical School Of Brown University in 1993, Dr. Johnson delivers high-quality medical care to the local community at 40 HOLLAND ST.

Dr. Johnson is affiliated with Atrius Health Inc and accepts Medicare assignment.

Frequently performed procedures and clinical services include established patient outpatient office visit, detection test by immunoassay with direct visual observation for influenza virus, detection test by immunoassay technique for severe acute respiratory syndrome coronavirus. Full Medicare procedure pricing transparency rates and service volume details are listed on this profile.

Practice Location & Contact Primary Location

Practice Address

40 Holland St
Harvard Vanguard Medical Associates

Somerville, MA 021442705

Telephone 6176296350

Associated Practice Facility / Clinic

🏢 Harvard Vanguard Medical Associates Facility NPI 1881756419

Medicare Profile & Education

Medical School

Warren Alpert Medical School Of Brown University

Graduation Year

1993

Medicare Assignment

✓ Accepts Assignment

Telehealth Flag

In-Person Only

Specialty Benchmarks & Practice Insights

Comparative analytics for Internal Medicine in Somerville, MA

Senior Veteran Specialist (>20 Yrs)

Practitioner Clinical Experience

33 Yrs +1.5 yrs vs City Avg

City Avg: 31.5 Yrs

State Avg: 29.3 Yrs

Regional Practice Density

37 Specialists

Practicing in Somerville, MA (7127 Statewide)

Telehealth Adoption Rate

40.5% Regional Adoption

In-Person Office Visits Only

Medicare Pricing Discount

69.0% Avg Savings

Under CMS Medicare Fee Schedule vs Standard Submitted Charges

Clinical Seniority & Experience Comparison

Dr. Johnson (33 Years) 33 Yrs

Somerville Specialty Average (31.5 Years) 31.5 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
99213 Established patient office or other outpatient visit, typically 15 minutes	447	344	$268.48	$89.50
87804 Detection test by immunoassay with direct visual observation for influenza virus	338	81	$49.00	$16.22
87426 Detection test by immunoassay technique for severe acute respiratory syndrome coronavirus	166	77	$106.00	$34.62
36415 Insertion of needle into vein for collection of blood sample	132	122	$20.00	$8.65
99214 Established patient office or other outpatient visit with moderate level of decision making, if using time, 30 minutes or more	128	127	$349.84	$131.71
85025 Complete blood cell count (red cells, white blood cell, platelets), automated test and automated differential white blood cell count	105	103	$31.00	$7.61
87635 Amplifed dna or rna probe detection of severe acute respiratory syndrome coronavirus 2 (covid-19) antigen	104	69	$209.00	$50.28
80051 Blood test panel for electrolytes (sodium potassium, chloride, carbon dioxide)	80	77	$28.00	$6.87
84520 Urea nitrogen level to assess kidney function	80	77	$16.00	$3.87
82565 Blood creatinine level	79	76	$21.00	$5.02
81002 Urinalysis, manual test	63	61	$10.00	$3.41
82947 Blood glucose (sugar) level	61	60	$16.00	$3.85
J0696 Injection, ceftriaxone sodium, per 250 mg	60	14	$23.00	$0.45
87086 Bacterial colony count, urine	57	55	$33.00	$7.91
99212 Established patient office or other outpatient visit with straightforward medical decision making, if using time, 10 minutes or more	40	37	$170.22	$58.99
87880 Detection test by immunoassay with direct visual observation for streptococcus, group a (strep)	31	28	$49.00	$16.20
80053 Blood test, comprehensive group of blood chemicals	28	28	$43.00	$10.35
87077 Bacterial culture for aerobic isolates	28	24	$33.00	$7.92
87081 Screening test for pathogenic organisms	24	24	$27.00	$6.50
87186 Evaluation of antimicrobial drug (antibiotic, antifungal, antiviral), microdilution or agar dilution	22	19	$35.00	$8.48
96365 Infusion into a vein for therapy, prevention, or diagnosis, 1 hour or less	20	20	$212.00	$70.94
83880 Natriuretic peptide (heart and blood vessel protein) level	17	17	$136.00	$38.47
85379 Coagulation function measurement, d-dimer; quantitative	13	13	$41.00	$9.98
85651 Red blood cell sedimentation rate, to detect inflammation, non-automated	11	11	$14.00	$4.18

HCPCS Code & Description	Services	Patients	Submitted Charge	Medicare Allowed
99213 Established patient office or other outpatient visit, typically 15 minutes	411	345	$266.03	$90.29
36415 Insertion of needle into vein for collection of blood sample	132	121	$17.82	$8.40
87804 Detection test by immunoassay with direct visual observation for influenza virus	112	36	$49.00	$16.22
99214 Established patient office or other outpatient visit with moderate level of decision making, if using time, 30 minutes or more	97	91	$346.00	$128.44
85025 Complete blood cell count (red cells, white blood cell, platelets), automated test and automated differential white blood cell count	96	93	$31.00	$7.61
82565 Blood creatinine level	70	68	$21.00	$5.02
80051 Blood test panel for electrolytes (sodium potassium, chloride, carbon dioxide)	70	68	$28.00	$6.87
84520 Urea nitrogen level to assess kidney function	70	68	$16.00	$3.87
87635 Amplifed dna or rna probe detection of severe acute respiratory syndrome coronavirus 2 (covid-19) antigen	64	41	$209.00	$50.28
99212 Established patient office or other outpatient visit with straightforward medical decision making, if using time, 10 minutes or more	59	32	$168.14	$56.57
87428 Detection test by immunoassay technique for severe acute respiratory syndrome coronavirus and influenza	53	38	$168.00	$30.32
87426 Detection test by immunoassay technique for severe acute respiratory syndrome coronavirus	51	32	$106.00	$34.62
82947 Blood glucose (sugar) level	47	46	$16.00	$3.85
81002 Urinalysis, manual test	45	43	$10.00	$3.41
87086 Bacterial colony count, urine	40	39	$33.00	$7.91
87880 Detection test by immunoassay with direct visual observation for streptococcus, group a (strep)	33	26	$49.00	$16.20
87081 Screening test for pathogenic organisms	31	24	$27.00	$6.50
U0003 Infectious agent detection by nucleic acid (dna or rna); severe acute respiratory syndrome coronavirus 2 (sars-cov-2) (coronavirus disease [covid-19]), amplified probe technique, making use of high throughput technologies as described by cms-2020-01-r	28	22	$209.00	$73.50
U0005 Infectious agent detection by nucleic acid (dna or rna); severe acute respiratory syndrome coronavirus 2 (sars-cov-2) (coronavirus disease [covid-19]), amplified probe technique, cdc or non-cdc, making use of high throughput technologies, completed within	28	22	$60.00	$24.50
85651 Red blood cell sedimentation rate, to detect inflammation, non-automated	22	22	$14.00	$4.18
87077 Bacterial culture for aerobic isolates	22	19	$33.00	$7.92
80053 Blood test, comprehensive group of blood chemicals	20	20	$43.00	$10.35
87186 Evaluation of antimicrobial drug (antibiotic, antifungal, antiviral), microdilution or agar dilution	17	15	$35.00	$8.48
J7030 Infusion, normal saline solution , 1000 cc	15	12	$6.00	$2.55
86140 Measurement C-reactive protein for detection of infection or inflammation	14	14	$21.00	$5.08
85379 Coagulation function measurement, d-dimer; quantitative	13	12	$41.00	$9.98
96372 Injection beneath the skin or into muscle for therapy, diagnosis, or prevention	12	11	$69.00	$14.88
83880 Natriuretic peptide (heart and blood vessel protein) level	12	12	$136.00	$38.47

HCPCS Code & Description	Services	Patients	Submitted Charge	Medicare Allowed
Q0138 Injection, ferumoxytol, for treatment of iron deficiency anemia, 1 mg (non-esrd use)	9,180	11	$3.00	$0.86
99213 Established patient office or other outpatient visit, typically 15 minutes	253	198	$238.00	$90.64
J3489 Injection, zoledronic acid, 1 mg	200	40	$89.00	$7.04
U0003 Infectious agent detection by nucleic acid (dna or rna); severe acute respiratory syndrome coronavirus 2 (sars-cov-2) (coronavirus disease [covid-19]), amplified probe technique, making use of high throughput technologies as described by cms-2020-01-r	73	54	$209.00	$73.92
U0005 Infectious agent detection by nucleic acid (dna or rna); severe acute respiratory syndrome coronavirus 2 (sars-cov-2) (coronavirus disease [covid-19]), amplified probe technique, cdc or non-cdc, making use of high throughput technologies, completed within	73	54	$30.00	$24.64
99214 Established patient office or other outpatient visit with moderate level of decision making, if using time, 30 minutes or more	70	68	$346.00	$123.55
J7050 Infusion, normal saline solution, 250 cc	64	54	$2.00	$0.66
99212 Established patient office or other outpatient visit with straightforward medical decision making, if using time, 10 minutes or more	60	29	$148.00	$60.34
36415 Insertion of needle into vein for collection of blood sample	58	51	$12.00	$2.96
87428 Detection test by immunoassay technique for severe acute respiratory syndrome coronavirus and influenza	49	39	$168.00	$30.52
96365 Infusion into a vein for therapy, prevention, or diagnosis, 1 hour or less	48	46	$212.00	$80.93
85025 Complete blood cell count (red cells, white blood cell, platelets), automated test and automated differential white blood cell count	43	42	$31.00	$7.65
84520 Urea nitrogen level to assess kidney function	33	28	$16.00	$3.90
80051 Blood test panel for electrolytes (sodium potassium, chloride, carbon dioxide)	33	28	$28.00	$6.91
82565 Blood creatinine level	33	28	$21.00	$5.05
87880 Detection test by immunoassay with direct visual observation for streptococcus, group a (strep)	29	20	$49.00	$16.29
81002 Urinalysis, manual test	28	28	$10.00	$3.43
87804 Detection test by immunoassay with direct visual observation for influenza virus	28	11	$49.00	$16.27
87086 Bacterial colony count, urine	26	26	$33.00	$7.94
87081 Screening test for pathogenic organisms	25	16	$27.00	$6.53
82947 Blood glucose (sugar) level	25	20	$16.00	$3.88
96374 Injection of drug or substance into a vein for therapy, diagnosis, or prevention	17	12	$151.00	$46.62
87077 Bacterial culture for aerobic isolates	16	15	$33.00	$7.97
87426 Detection test by immunoassay technique for severe acute respiratory syndrome coronavirus	15	13	$106.00	$34.71
87186 Evaluation of antimicrobial drug (antibiotic, antifungal, antiviral), microdilution or agar dilution	14	13	$35.00	$8.53

HCPCS Code & Description	Services	Patients	Submitted Charge	Medicare Allowed
Q0138 Injection, ferumoxytol, for treatment of iron deficiency anemia, 1 mg (non-esrd use)	11,220	13	$3.00	$0.96
J3489 Injection, zoledronic acid, 1 mg	250	50	$89.00	$10.06
99213 Established patient office or other outpatient visit, typically 15 minutes	197	136	$223.93	$102.24
99214 Established patient office or other outpatient visit with moderate level of decision making, if using time, 30 minutes or more	109	85	$320.26	$145.46
36415 Insertion of needle into vein for collection of blood sample	78	63	$12.00	$3.00
J7050 Infusion, normal saline solution, 250 cc	71	64	$2.00	$0.68
96365 Infusion into a vein for therapy, prevention, or diagnosis, 1 hour or less	63	51	$212.00	$86.94
85025 Complete blood cell count (red cells, white blood cell, platelets), automated test and automated differential white blood cell count	57	51	$31.00	$7.77
U0003 Infectious agent detection by nucleic acid (dna or rna); severe acute respiratory syndrome coronavirus 2 (sars-cov-2) (coronavirus disease [covid-19]), amplified probe technique, making use of high throughput technologies as described by cms-2020-01-r	41	33	$209.00	$75.00
99212 Established patient office or other outpatient visit with straightforward medical decision making, if using time, 10 minutes or more	41	28	$137.85	$64.03
U0005 Infectious agent detection by nucleic acid (dna or rna); severe acute respiratory syndrome coronavirus 2 (sars-cov-2) (coronavirus disease [covid-19]), amplified probe technique, cdc or non-cdc, making use of high throughput technologies, completed within	41	33	$30.00	$25.00
87426 Detection test by immunoassay technique for severe acute respiratory syndrome coronavirus	33	29	$106.00	$35.33
82565 Blood creatinine level	32	27	$21.00	$5.12
84520 Urea nitrogen level to assess kidney function	30	26	$16.00	$3.95
80051 Blood test panel for electrolytes (sodium potassium, chloride, carbon dioxide)	28	25	$28.00	$7.01
87804 Detection test by immunoassay with direct visual observation for influenza virus	24	11	$49.00	$16.55
81002 Urinalysis, manual test	22	19	$10.00	$3.48
82947 Blood glucose (sugar) level	21	17	$16.00	$3.93
87880 Detection test by immunoassay with direct visual observation for streptococcus, group a (strep)	17	14	$49.00	$16.53
87086 Bacterial colony count, urine	16	13	$33.00	$8.07
85379 Coagulation function measurement, d-dimer; quantitative	15	15	$41.00	$10.18
96372 Injection beneath the skin or into muscle for therapy, diagnosis, or prevention	12	11	$67.00	$16.17

HCPCS Code & Description	Services	Patients	Submitted Charge	Medicare Allowed
99214 Established patient office or other outpatient visit with moderate level of decision making, if using time, 30 minutes or more	161	143	$300.00	$121.57
99213 Established patient office or other outpatient visit, typically 15 minutes	83	79	$202.00	$83.65
36415 Insertion of needle into vein for collection of blood sample	69	61	$12.00	$2.98
85025 Complete blood cell count (red cells, white blood cell, platelets), automated test and automated differential white blood cell count	49	44	$31.00	$7.73
U0003 Infectious agent detection by nucleic acid (dna or rna); severe acute respiratory syndrome coronavirus 2 (sars-cov-2) (coronavirus disease [covid-19]), amplified probe technique, making use of high throughput technologies as described by cms-2020-01-r	33	33	$209.00	$99.94
81002 Urinalysis, manual test	26	24	$10.00	$3.46
87086 Bacterial colony count, urine	24	22	$33.00	$8.01
87804 Detection test by immunoassay with direct visual observation for influenza virus	20	12	$49.00	$16.29
87077 Bacterial culture for aerobic isolates	18	16	$33.00	$8.05
82565 Blood creatinine level	17	17	$21.00	$5.11
84520 Urea nitrogen level to assess kidney function	16	16	$16.00	$3.94
80051 Blood test panel for electrolytes (sodium potassium, chloride, carbon dioxide)	16	16	$28.00	$6.99
80053 Blood test, comprehensive group of blood chemicals	15	15	$43.00	$10.52
87186 Evaluation of antimicrobial drug (antibiotic, antifungal, antiviral), microdilution or agar dilution	15	13	$35.00	$8.62
87880 Detection test by immunoassay with direct visual observation for streptococcus, group a (strep)	14	14	$49.00	$16.32
82947 Blood glucose (sugar) level	14	14	$16.00	$3.92
80048 Blood test, basic group of blood chemicals (calcium, total)	11	11	$34.00	$8.38

HCPCS Code & Description	Services	Patients	Submitted Charge	Medicare Allowed
J3489 Injection, zoledronic acid, 1 mg	329	71	$59.59	$11.52
99214 Established patient office or other outpatient visit with moderate level of decision making, if using time, 30 minutes or more	197	184	$297.00	$118.82
99213 Established patient office or other outpatient visit, typically 15 minutes	150	143	$202.00	$82.00
96365 Infusion into a vein for therapy, prevention, or diagnosis, 1 hour or less	96	88	$212.00	$81.28
J7050 Infusion, normal saline solution, 250 cc	60	56	$2.00	$0.61
36415 Insertion of needle into vein for collection of blood sample	57	54	$12.00	$2.94
85025 Complete blood cell count (red cells, white blood cell, platelets), automated test and automated differential white blood cell count	37	36	$31.00	$8.46
87086 Bacterial colony count, urine	32	32	$33.00	$8.79
81002 Urinalysis, manual test	28	28	$10.00	$3.41
87880 Detection test by immunoassay with direct visual observation for streptococcus, group a (strep)	22	21	$49.00	$16.20
96366 Infusion into a vein for therapy, prevention, or diagnosis, each additional hour	20	20	$63.00	$24.61
82947 Blood glucose (sugar) level	20	20	$16.00	$4.28
82565 Blood creatinine level	19	19	$21.00	$5.58
80051 Blood test panel for electrolytes (sodium potassium, chloride, carbon dioxide)	19	19	$28.00	$7.63
84520 Urea nitrogen level to assess kidney function	19	19	$16.00	$4.30
80076 Liver function blood test panel	14	14	$33.00	$8.90
87804 Detection test by immunoassay with direct visual observation for influenza virus	13	12	$49.00	$16.22

HCPCS Code & Description	Services	Patients	Submitted Charge	Medicare Allowed
J3489 Injection, zoledronic acid, 1 mg	321	68	$30.84	$13.62
99214 Established patient office or other outpatient visit with moderate level of decision making, if using time, 30 minutes or more	155	144	$271.34	$118.12
99213 Established patient office or other outpatient visit, typically 15 minutes	122	111	$185.42	$79.62
96365 Infusion into a vein for therapy, prevention, or diagnosis, 1 hour or less	98	84	$194.18	$84.17
J7050 Infusion, normal saline solution, 250 cc	93	81	$1.24	$0.59
36415 Insertion of needle into vein for collection of blood sample	45	44	$7.00	$2.94
96366 Infusion into a vein for therapy, prevention, or diagnosis, each additional hour	35	34	$57.00	$24.93
85025 Complete blood cell count (red cells, white blood cell, platelets), automated test and automated differential white blood cell count	30	30	$24.00	$9.40
87400 Detection test for Influenza virus, A or B	22	11	$36.00	$14.51
81002 Urinalysis, manual test	19	19	$8.00	$3.41
87880 Detection test by immunoassay with direct visual observation for streptococcus, group a (strep)	17	17	$36.76	$15.34
87086 Bacterial colony count, urine	17	17	$25.47	$9.76
G0008 Administration of influenza virus vaccine	13	13	$23.00	$22.54
87077 Bacterial culture for aerobic isolates	12	12	$17.00	$9.77
87804 Detection test by immunoassay with direct visual observation for influenza virus	12	11	$36.00	$16.22
87186 Evaluation of antimicrobial drug (antibiotic, antifungal, antiviral), microdilution or agar dilution	12	11	$27.00	$10.46
84520 Urea nitrogen level to assess kidney function	11	11	$13.00	$4.78
82565 Blood creatinine level	11	11	$16.00	$6.20

HCPCS Code & Description	Services	Patients	Submitted Charge	Medicare Allowed
J3489 Injection, zoledronic acid, 1 mg	176	41	$49.00	$12.63
99214 Established patient office or other outpatient visit with moderate level of decision making, if using time, 30 minutes or more	168	158	$206.36	$112.60
96365 Infusion into a vein for therapy, prevention, or diagnosis, 1 hour or less	74	54	$140.38	$75.91
J7050 Infusion, normal saline solution, 250 cc	64	49	$1.00	$0.49
99213 Established patient office or other outpatient visit, typically 15 minutes	54	50	$142.50	$74.61
36415 Insertion of needle into vein for collection of blood sample	38	37	$6.00	$2.94
87400 Detection test for Influenza virus, A or B	26	13	$29.62	$14.46
85025 Complete blood cell count (red cells, white blood cell, platelets), automated test and automated differential white blood cell count	23	23	$19.52	$10.45
81002 Urinalysis, manual test	22	21	$7.00	$3.43
87086 Bacterial colony count, urine	20	19	$55.25	$10.85
87077 Bacterial culture for aerobic isolates	15	12	$13.00	$7.04
87186 Evaluation of antimicrobial drug (antibiotic, antifungal, antiviral), microdilution or agar dilution	15	13	$21.00	$11.62
80048 Blood test, basic group of blood chemicals (calcium, total)	15	15	$21.00	$11.37

Medical Specialties & State Licenses

CMS Verified: 2021-02-18

Internal Medicine Primary Specialty

NUCC Taxonomy Code: 207R00000X

State License MA 151587

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.

Hospital & Practice Group Affiliations

Atrius Health Inc

77 Herrick St, Beverly, MA 019152734

Phone: 9789274110

Atrius Health Inc

100 2nd Ave, Needham, MA 024942809

Phone: 7817264800

Atrius Health Inc

40 Holland St, Somerville, MA 021442705

Phone: 6176296000

Atrius Health Inc

133 Brookline Ave, Boston, MA 022153904

Phone: 6174211000

Atrius Health Inc

291 Independence Dr, Chestnut Hill, MA 024673628

Phone: 6173252800

Practice Associates & Co-Workers

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

12 Associated Practitioners

Dr. James Liu , MD

Internal Medicine

NPI 1114983533

Doctor of Medicine (M.D.)

Dr. Tatiana Slavsky , MD

Internal Medicine

NPI 1124060736

Doctor of Medicine (M.D.)

Suzanne Longley , NP-C

Nurse Practitioner - Family

NPI 1144563115

Nurse Practitioner (Certified)

Vlasta Lavalle , NP

Nurse Practitioner - Adult Health

NPI 1316076334

Nurse Practitioner

Dr. Rachel Berger , MD

Internal Medicine

NPI 1326019456

Doctor of Medicine (M.D.)

Lisa Ruggiero , NP

Nurse Practitioner - Primary Care

NPI 1366922460

Nurse Practitioner

Career & Practice History Timeline

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

6 Historical Events

✅

NPI Profile Active February 25, 2013

NPI status registered as active in NPPES database

📍

Updated Practice Location February 25, 2013

Registered at 40 HOLLAND ST, HARVARD VANGUARD MEDICAL ASSOCIATES, SOMERVILLE, MA 021442705 (Tel: 6176296350)

📍

Updated Business Mailing Address February 25, 2013

Registered at 40 HOLLAND ST, HARVARD VANGUARD MEDICAL ASSOCIATES, SOMERVILLE, MA 021442705 (Tel: 6176296350)

👤

Provider Name / Credentials Updated February 25, 2013

Recorded as GREGORY JOHNSON, MD

🎓

Medical Taxonomy / Specialty Registered (Primary Specialty) February 25, 2013

Internal Medicine (License #151587 in MA)

🟢

Initial NPI Registration & Enumeration August 14, 2006

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: 1942213509

Entity Type:

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

Enumeration Date: August 14, 2006

Last Update: February 18, 2021

Sole Proprietor: No

Update or Correct Profile

Mailing Address

40 Holland St, Harvard Vanguard Medical Associates

Somerville, MA 021442705

Phone: 6176296350

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.