Aussama Khalaf Nassar, MD

Offices

2 locations · Stanford Health Care · 3,152 clinicians in this group

Looking this up.

Hospitals listed: Stanford Health Care. That is not proof they admit you there this week.

Plans that list them

13 plans · 2 carriers

A missing listing does not mean out of network. Directories change, and a listing does not cover every office. Call Dr. Nassar’s office to confirm they take your plan. Ask about the office you use, its medical group, referrals and appointments.

13 of 13 plans

Sort by

Plans whose provider directory lists this clinician

Alignment Health BreathEasy (HMO C-SNP)	Alignment Health Plan	Listed	Oct 3, 2026
Alignment Health Clarity (HMO C-SNP)	Alignment Health Plan	Listed	Oct 3, 2026
Alignment Health Harmony (HMO)	Alignment Health Plan	Listed	Oct 3, 2026
Alignment Health Heart & Diabetes (HMO C-SNP)	Alignment Health Plan	Listed	Oct 3, 2026
Alignment Health Heart & Diabetes CalPlus (HMO C-SNP)	Alignment Health Plan	Listed	Oct 3, 2026
Alignment Health Heart & Diabetes Care (HMO C-SNP)	Alignment Health Plan	Listed	Sep 28, 2026
Alignment Health Heart & Diabetes Choice (HMO C-SNP)	Alignment Health Plan	Listed	Sep 28, 2026
Alignment Health Honor+ Plan (HMO)	Alignment Health Plan	Listed	Oct 3, 2026
Alignment Health My Choice CalCare (HMO)	Alignment Health Plan	Listed	Oct 3, 2026
Alignment Health Silicon (HMO C-SNP)	Alignment Health Plan	Listed	Oct 3, 2026
Alignment Health smartHMO (HMO)	Alignment Health Plan	Listed	Oct 3, 2026
Alignment Health the ONE (HMO)	Alignment Health Plan	Listed	Oct 3, 2026
DualConnect (HMO D-SNP)	Santa Clara Family Health Plan	Listed	Sep 1, 2026

California Medical Board record

Licence C148059 · Current

Licensed to practise in California · since 2017 · expires 2027-02-28 · University of Al-Mustansiriyah College of Medicine.

No disciplinary actions, convictions, malpractice judgments or citations in this record.

Hospitals they work in

1 hospital

These rate the hospital, not this clinician. Most measures at most hospitals are no different from the national rate.

Stanford Health CareStanford, CAAcute Care Hospital · Voluntary non-profit - Private · Has an emergency departmentPart of Stanford Health Care, which runs 3 hospitalsHome of Stanford Cancer Institute, a National Cancer Institute designated comprehensive cancer centrePatients rate it 4 of 5 · 83% would definitely recommend it
Overall rating: 5 of 5 starsWorse than the national rate — Perioperative pulmonary embolism or deep vein thrombosis rate: 5.31 (4.24 to 6.37) · 8,661 cases, Jul 2022 – Jun 2024Worse than the national rate — Rate of inpatient admissions for patients receiving outpatient chemotherapy: 14.1 (12.7 to 15.7) · 2,191 cases, Jan 2024 – Dec 2024Better than the national rate — Postoperative respiratory failure rate: 4.08 (1.95 to 6.21) · 5,296 cases, Jul 2022 – Jun 2024Better than the national rate — Catheter Associated Urinary Tract Infections (ICU + select Wards): 0.317, Oct 2024 – Sep 2025Better than the national rate — Clostridium Difficile (C.Diff): 0.446, Oct 2024 – Sep 2025Better than the national rate — SSI - Colon Surgery: 0.241, Oct 2024 – Sep 2025Better than the national rate — Ratio of unplanned hospital visits after hospital outpatient surgery: 0.7 (0.6 to 0.9) · 3,348 cases, Jan 2024 – Dec 2024

See every measure and the patient survey for Stanford Health Care

Behind the star rating — Deaths: 5 better, 3 the same, 0 worse of 8 measures. Safety: 3 better, 5 the same, 0 worse of 8 measures. Readmissions: 2 better, 5 the same, 4 worse of 11 measures. The star rating is worked out from an earlier period than the measures below, so the two can disagree.

Sort by

Every scored measure at Stanford Health Care

Perioperative pulmonary embolism or deep vein thrombosis rateComplications and deaths	5.31 (4.24 to 6.37) · 8,661 cases	Worse	Jul 2022 – Jun 2024
Rate of inpatient admissions for patients receiving outpatient chemotherapyUnplanned return visits	14.1 (12.7 to 15.7) · 2,191 cases	Worse	Jan 2024 – Dec 2024
Postoperative respiratory failure rateComplications and deaths	4.08 (1.95 to 6.21) · 5,296 cases	Better	Jul 2022 – Jun 2024
Catheter Associated Urinary Tract Infections (ICU + select Wards)Infections	0.317	Better	Oct 2024 – Sep 2025
Clostridium Difficile (C.Diff)Infections	0.446	Better	Oct 2024 – Sep 2025
SSI - Colon SurgeryInfections	0.241	Better	Oct 2024 – Sep 2025
Ratio of unplanned hospital visits after hospital outpatient surgeryUnplanned return visits	0.7 (0.6 to 0.9) · 3,348 cases	Better	Jan 2024 – Dec 2024
Abdominopelvic accidental puncture or laceration rateComplications and deaths	1.06 (0.45 to 1.67) · 5,374 cases	No different	Jul 2022 – Jun 2024
CMS Medicare PSI 90: Patient safety and adverse events compositeComplications and deaths	0.86 (0.72 to 1)	No different	Jul 2022 – Jun 2024
Death rate among surgical inpatients with serious treatable complicationsComplications and deaths	166.09 (137.88 to 194.3) · 470 cases	No different	Jul 2022 – Jun 2024
Death rate for CABG surgery patientsComplications and deaths	1.1 · 192 cases	None	Jul 2022 – Jun 2025
Death rate for COPD patientsComplications and deaths	6.4 · 146 cases	None	Jul 2022 – Jun 2025
Death rate for heart attack patientsComplications and deaths	9.7 · 253 cases	None	Jul 2022 – Jun 2025
Death rate for heart failure patientsComplications and deaths	6.3 · 880 cases	None	Jul 2022 – Jun 2025
Death rate for pneumonia patientsComplications and deaths	10.3 · 935 cases	None	Jul 2022 – Jun 2025
Death rate for stroke patientsComplications and deaths	8.7 · 501 cases	None	Jul 2023 – Jun 2025
Hybrid Hospital-Wide All-Cause Risk Standardized Mortality RateComplications and deaths	2.1 · 7,730 cases	None	Jul 2024 – Jun 2025
Iatrogenic pneumothorax rateComplications and deaths	0.13 (0 to 0.27) · 20,799 cases	No different	Jul 2022 – Jun 2024
In-hospital fall-associated fracture rateComplications and deaths	0.28 (0.14 to 0.43) · 23,182 cases	No different	Jul 2022 – Jun 2024
Postoperative acute kidney injury requiring dialysis rateComplications and deaths	0.94 (0.2 to 1.68) · 5,694 cases	No different	Jul 2022 – Jun 2024
Postoperative hemorrhage or hematoma rateComplications and deaths	2.36 (1.54 to 3.19) · 7,846 cases	No different	Jul 2022 – Jun 2024
Postoperative sepsis rateComplications and deaths	5.2 (3.76 to 6.64) · 5,603 cases	No different	Jul 2022 – Jun 2024
Postoperative wound dehiscence rateComplications and deaths	1.38 (0.23 to 2.53) · 2,211 cases	No different	Jul 2022 – Jun 2024
Pressure ulcer rateComplications and deaths	0.52 (0.21 to 0.83) · 19,915 cases	No different	Jul 2022 – Jun 2024
Rate of complications for hip/knee replacement patientsComplications and deaths	3.6 · 416 cases	None	Apr 2023 – Mar 2025
Central Line Associated Bloodstream Infection (ICU + select Wards)Infections	0.869	No different	Oct 2024 – Sep 2025
MRSA BacteremiaInfections	0.857	No different	Oct 2024 – Sep 2025
SSI - Abdominal HysterectomyInfections	0.368	No different	Oct 2024 – Sep 2025
Acute Myocardial Infarction (AMI) 30-Day Readmission RateUnplanned return visits	16.2 · 247 cases	None	Jul 2023 – Jun 2025
Heart failure (HF) 30-Day Readmission RateUnplanned return visits	20.5 · 1,021 cases	None	Jul 2023 – Jun 2025
Hospital return days for heart attack patientsUnplanned return visits	47.8 · 258 cases	None	Jul 2022 – Jun 2025
Hospital return days for heart failure patientsUnplanned return visits	-1.6 · 990 cases	None	Jul 2022 – Jun 2025
Hospital return days for pneumonia patientsUnplanned return visits	20.8 · 976 cases	None	Jul 2022 – Jun 2025
Pneumonia (PN) 30-Day Readmission RateUnplanned return visits	16.5 · 959 cases	None	Jul 2023 – Jun 2025
Rate of emergency department (ED) visits for patients receiving outpatient chemotherapyUnplanned return visits	5.2 (4.4 to 6.2) · 2,191 cases	No different	Jan 2024 – Dec 2024
Rate of readmission after hip/knee replacementUnplanned return visits	5.1 · 425 cases	None	Jul 2023 – Jun 2025
Rate of readmission for CABGUnplanned return visits	9.6 · 158 cases	None	Jul 2023 – Jun 2025
Rate of readmission for chronic obstructive pulmonary disease (COPD) patientsUnplanned return visits	19.6 · 183 cases	None	Jul 2023 – Jun 2025
Rate of unplanned hospital visits after colonoscopy (per 1,000 colonoscopies)Unplanned return visits	12.7 (10.4 to 15.4) · 4,578 cases	No different	Jan 2022 – Dec 2024

What patients said (6,810 patients answered, 25% of those asked)

Sort by

Patient survey stars by topic at Stanford Health Care

Cleanliness	4
Nurse communication	4
Doctor communication	4
Communication about medicines	3
Discharge information	4
Overall hospital rating	4
Quietness	2
Recommend hospital	5

Sort by

Share of patients giving the best answer at Stanford Health Care

Room was "always" clean	75%
Nurses "always" communicated well	82%
Doctors "always" communicated well	81%
Staff "always" explained	63%
Yes, staff "did" give patients this information	89%
Yes, staff "did" give patients information about help after discharge	89%
Doctors "always" explained things so they could understand	76%
Doctors "always" listened carefully	80%
Doctors "always" treated them with courtesy and respect	87%
Patients who gave a rating of "9" or "10" (high)	79%
Staff "always" explained new medications	76%
Nurses "always" explained things so they could understand	77%
Nurses "always" listened carefully	79%
Nurses "always" treated them with courtesy and respect	88%
"Always" quiet at night	53%
"YES", patients would definitely recommend the hospital	83%
Staff "always" explained possible side effects	50%
Yes, staff "did" give patients information about possible symptoms	90%

Original Medicare doctor bills

$69,537

Medicare paid this office $69,537 for 285 people.

This is what Medicare paid the clinician — not Medicare Advantage, and not the pharmacy.

Sort by

Largest Original Medicare bills

Critical care, first 30-74 minutes	44	$17,258	$186
Subsequent hospital care with straightforward or low level of medical decision making, per day at least 25 minutes	126	$9,574	$43
Subsequent hospital care with moderate levelof medical decision making at least 35 minutes	45	$4,928	$69
Hospital discharge day management, 30 minutes or less	41	$2,929	$71
Initial hospital care with straightforward or low level of medical decision making, per day at least 40 minutes	30	$2,118	$71

Procedures Medicare counted

Sort by

Procedure volume Medicare published

Colonoscopy	1-10	None
Hernia repair - groin (open)	1-10	None
Hernia repair (minimally invasive)	1-10	None
Removal of tissue	1-10	None
Upper gastrointestinal (GI) endoscopy for acid reflux	1-10	None

Who their Medicare patients are

285 Original Medicare patients in 2024. Average age 77 · Under 65 7% · 85 and older 25% · Women 46% · Also on Medicaid 32% · Health risk score 2.69. Above the middle of the specialty; the typical general surgery clinician is at 1.69.

Conditions among them: High blood pressure 75% · Coronary heart disease 47% · Diabetes 46% · Atrial fibrillation 41% · Chronic kidney disease 39% · Heart failure 35% · Depression 32% · Dementia 30% · Stroke 23% · Cancer 21% · COPD 19%.

The office billed $501,452, Medicare allowed $88,870 and paid $69,537; for 587 services of 56 kinds.

Original Medicare patients only. A risk score of 1.0 is the average Medicare patient; higher means sicker. Any count under 11 is hidden.

Year by year

Sort by

Original Medicare by year

2024	285	587	77	2.69	$501,452	$69,537
2023	276	636	74	2.17	$666,213	$79,646
2022	192	465	74	2.23	$461,637	$63,844
2021	220	497	74	2.22	$455,216	$63,180
2020	175	457	72	2.20	$601,030	$74,936
2019	236	499	74	1.95	$534,789	$72,891
2018	213	502	74	2.18	$460,309	$62,433
2017	112	202	73	1.92	$222,497	$31,924

Original Medicare only. A service billed for fewer than 11 people in a year is hidden, so the lines can add up to less than the year's total.

See the services billed each year

2023: 7 services

Sort by

Original Medicare services billed in 2023

Critical care, first 30-74 minutes	73	$33,663	$191
Subsequent hospital care with straightforward or low level of medical decision making, per day at least 25 minutes	128	$9,461	$45
Hospital discharge day management, 30 minutes or less	34	$2,505	$74
Subsequent hospital care with moderate levelof medical decision making at least 35 minutes	23	$2,116	$73
Initial hospital care with straightforward or low level of medical decision making, per day at least 40 minutes	24	$2,041	$73
Return visit (30+ min)	18	$1,716	$82
New patient visit (30+ min)	22	$1,591	$72

2022: 8 services

Sort by

Original Medicare services billed in 2022

Critical care, first 30-74 minutes	37	$23,285	$196
Subsequent hospital care with moderate levelof medical decision making at least 35 minutes	54	$5,359	$64
New patient visit (45+ min)	22	$2,635	$120
Subsequent hospital care with moderate levelof medical decision making at least 50 minutes	17	$2,534	$94
Return visit (30+ min)	19	$2,018	$88
Subsequent hospital care with straightforward or low level of medical decision making, per day at least 25 minutes	41	$1,893	$34
Hospital discharge day management, 30 minutes or less	21	$1,417	$67
Initial hospital care with straightforward or low level of medical decision making, per day at least 40 minutes	14	$1,266	$90

2021: 9 services

Sort by

Original Medicare services billed in 2021

Critical care, first 30-74 minutes	44	$29,101	$199
Subsequent hospital care with moderate levelof medical decision making at least 35 minutes	66	$6,241	$66
Subsequent hospital care with moderate levelof medical decision making at least 50 minutes	17	$3,055	$95
Subsequent hospital care with straightforward or low level of medical decision making, per day at least 25 minutes	53	$2,734	$36
New patient visit (45+ min)	18	$2,338	$130
Return visit (30+ min)	14	$1,434	$96
Hospital discharge day management, 30 minutes or less	17	$1,155	$68
Initial hospital care with straightforward or low level of medical decision making, per day at least 40 minutes	11	$1,014	$92
New patient visit (30+ min)	12	$928	$77

2020: 7 services

Sort by

Original Medicare services billed in 2020

Critical care, first 30-74 minutes	62	$34,215	$202
Subsequent hospital care with straightforward or low level of medical decision making, per day at least 25 minutes	45	$2,579	$36
Initial hospital care with straightforward or low level of medical decision making, per day at least 40 minutes	21	$1,992	$95
Hospital discharge day management, 30 minutes or less	24	$1,677	$70
Subsequent hospital care with moderate levelof medical decision making at least 35 minutes	16	$1,356	$68
New patient visit (30+ min)	17	$1,126	$66
Return visit (30+ min)	11	$841	$70

2019: 6 services

Sort by

Original Medicare services billed in 2019

Critical care, first 30-74 minutes	92	$38,248	$194
Subsequent hospital care with straightforward or low level of medical decision making, per day at least 25 minutes	60	$2,871	$35
Initial hospital care with straightforward or low level of medical decision making, per day at least 40 minutes	29	$2,596	$90
Hospital discharge day management, 30 minutes or less	35	$2,329	$67
New patient visit (30+ min)	23	$1,470	$64
Short return visit (20+ min)	15	$907	$45

2018: 5 services

Sort by

Original Medicare services billed in 2018

Critical care, first 30-74 minutes	72	$35,472	$196
Subsequent hospital care with straightforward or low level of medical decision making, per day at least 25 minutes	81	$5,026	$35
Initial hospital care with straightforward or low level of medical decision making, per day at least 40 minutes	33	$3,054	$90
Hospital discharge day management, 30 minutes or less	18	$1,203	$67
Subsequent hospital care with moderate levelof medical decision making at least 35 minutes	13	$915	$65

2017: 3 services

Sort by

Original Medicare services billed in 2017

Critical care, first 30-74 minutes	45	$18,126	$195
Initial hospital care with straightforward or low level of medical decision making, per day at least 40 minutes	17	$1,525	$90
Subsequent hospital care with straightforward or low level of medical decision making, per day at least 25 minutes	22	$1,048	$35

Medicaid work

$1,051 in 2024

Medicaid paid $1,051 for 81 billed services this clinician did in 2024, up to 16 people in a month for one service.

Medicaid and CHIP claims where this clinician did the service, fee-for-service and managed care together. Any month with fewer than 11 patients is hidden, so small Medicaid practices undercount.

Sort by

Largest Medicaid services in 2024

SBSQ HOSPITAL IP/OBS CARE SF/LOW MDM 25 MINUTES	55	$593
SBSQ HOSPITAL IP/OBS CARE MOD MDM 35 MINUTES	26	$458

Sort by

Medicaid work by year

2024	81	2	16	$1,051
2023	307	3	28	$10,133
2022	37	2	13	$781
2021	53	1	17	$4,966
2019	35	1	15	$687
2018	45	1	14	$10,529

See the largest Medicaid services in earlier years

2023

Sort by

Largest Medicaid services in 2023

Critical care, evaluation and management of the critically ill or critically injured patient; first 30-74 minutes	103	$5,976
SBSQ HOSPITAL IP/OBS CARE SF/LOW MDM 25 MINUTES	190	$3,845
Hospital inpatient or observation discharge day management; 30 minutes or less on the date of the encounter	14	$312

2022

Sort by

Largest Medicaid services in 2022

SBSQ HOSPITAL IP/OBS CARE MOD MDM 35 MINUTES	19	$404
SBSQ HOSPITAL IP/OBS CARE SF/LOW MDM 25 MINUTES	18	$377

2021

Sort by

Largest Medicaid services in 2021

Critical care, evaluation and management of the critically ill or critically injured patient; first 30-74 minutes	53	$4,966

2019

Sort by

Largest Medicaid services in 2019

SBSQ HOSPITAL IP/OBS CARE SF/LOW MDM 25 MINUTES	35	$687

2018

Sort by

Largest Medicaid services in 2018

Critical care, evaluation and management of the critically ill or critically injured patient; first 30-74 minutes	45	$10,529

Money from drug and device companies

$4,427 in 2025

Sort by

Industry payments by year

2025	1	11	None	$4,427
2024	2	2	None	$106
2023	1	1	None	$89
2022	1	5	None	$374
2020	1	2	None	$86
2019	2	6	None	$408

Paid work is consulting, speaking, honoraria and royalties, as opposed to meals and travel.

A payment is not proof that care is biased.

Sort by

Payments by company

Intuitive Surgical	Davinci Xi	$4,427	11 payments Education for Da Vinci Surgical System · 2025-06-24 · $114 Meals for Da Vinci Surgical System · 2025-06-03 · $28 Meals for Da Vinci Surgical System · 2025-06-02 · $16 Education for Davinci Xi · 2025-06-02 · $2,500 Travel for Da Vinci Surgical System · 2025-05-22 · $207 Travel for Da Vinci Surgical System · 2025-05-12 · $19 Travel for Da Vinci Surgical System · 2025-05-12 · $174 Meals for Da Vinci Surgical System · 2025-04-11 · $378 Travel for Da Vinci Surgical System · 2025-03-12 · $37 Travel for Da Vinci Surgical System · 2025-03-12 · $45 Travel for Da Vinci Surgical System · 2025-03-12 · $909

See all 11 published payments

Sort by

Every published payment

Intuitive Surgical	Education · 2025-06-24	Da Vinci Surgical System	$114
Intuitive Surgical	Meals · 2025-06-03	Da Vinci Surgical System	$28
Intuitive Surgical	Meals · 2025-06-02	Da Vinci Surgical System	$16
Intuitive Surgical	Education · 2025-06-02	Davinci Xi	$2,500
Intuitive Surgical	Travel · 2025-05-22	Da Vinci Surgical System	$207
Intuitive Surgical	Travel · 2025-05-12	Da Vinci Surgical System	$19
Intuitive Surgical	Travel · 2025-05-12	Da Vinci Surgical System	$174
Intuitive Surgical	Meals · 2025-04-11	Da Vinci Surgical System	$378
Intuitive Surgical	Travel · 2025-03-12	Da Vinci Surgical System	$37
Intuitive Surgical	Travel · 2025-03-12	Da Vinci Surgical System	$45
Intuitive Surgical	Travel · 2025-03-12	Da Vinci Surgical System	$909

See earlier years (2024, 2023, 2022, 2020, 2019)

2024: $106

Sort by

Payments by company in 2024

Teleflex	Quikclot	$99	1 payment Meals for Quikclot · 2024-08-02 · $99
Intuitive Surgical	Da Vinci Surgical System	$7	1 payment Meals for Da Vinci Surgical System · 2024-03-26 · $7

2023: $89

Sort by

Payments by company in 2023

Teleflex	Quikclot	$89	1 payment Meals for Quikclot · 2023-08-18 · $89

2022: $374

Sort by

Payments by company in 2022

Medical Device Business Services	None	$374	5 payments Meals · 2022-10-01 · $36 Meals · 2022-10-01 · $59 Meals · 2022-10-01 · $6 Travel · 2022-09-30 · $192 Travel · 2022-09-30 · $81

2020: $86

Sort by

Payments by company in 2020

Intuitive Surgical	Da Vinci Surgical System	$86	2 payments Meals for Da Vinci Surgical System · 2020-01-21 · $64 Meals for Da Vinci Surgical System · 2020-01-21 · $22

2019: $408

Sort by

Payments by company in 2019

Intuitive Surgical	Da Vinci Surgical System	$302	5 payments Meals for Da Vinci Surgical System · 2019-11-13 · $4 Meals for Da Vinci Surgical System · 2019-11-13 · $40 Meals for Da Vinci Surgical System · 2019-11-13 · $16 Meals for Da Vinci Surgical System · 2019-09-10 · $14 Travel for Da Vinci Surgical System · 2019-09-05 · $228
Prescient Surgical	Cleancision	$106	1 payment Meals for Cleancision · 2019-01-25 · $106

Checkups this office reported

Medicare did not publish checkup rates for this clinician.

Medicare’s overall office score: 76.5 / 100; Scores the office’s reporting and systems. It is not a grade for how the doctor treats you.

Professional record

NPI: 1326589870
Licence: CA C148059California C148059: Current · expires 2027-02-28
Group: Stanford Health Care
Video visits: Lists video visits
Gender: Male

More record details

Sole proprietor: No
Taxonomy: Surgery (208600000X); Federal specialty code 2086S0102X (2086S0102X); Federal specialty code 2086S0127X (2086S0127X)
Mailing address: 300 Pasteur Dr, Palo Alto, CA, 94305
NPI first listed: 2017-03-16
NPI last updated: 2024-04-27
NPI record certified: 2024-04-27

This is when the NPI record was last certified, not a medical board exam.