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Kelly Lynn Ernst, MD

Pathology · Stanford

NPI 1043674195

Medicare standing
Clear
Enrolled, allowed to bill and order, not excluded
Plans that list them
1
1 carrier
Office
1

Offices

1 location · Stanford Health Care · 3,152 clinicians in this group

Looking this up.

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

Plans that list them

1 plan · 1 carrier

A missing listing does not mean out of network. Directories change, and a listing does not cover every office. Call Dr. Ernst’s office at (650) 723-4000 to confirm they take your plan. Ask about the office you use, its medical group, referrals and appointments.

Plans whose provider directory lists this clinician
DualConnect (HMO D-SNP)Santa Clara Family Health PlanListedSep 1, 2026

California Medical Board record

Licence A151114 · Current

Licensed to practise in California · since 2017 · expires 2027-07-31 · David Geffen School of Medicine at UCLA.

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

Hospitals they work in

2 hospitals

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
  • Stanford Health Care Tri-ValleyPleasanton, CAAcute Care Hospital · Voluntary non-profit - Private · Has an emergency department · Birthing-friendlyPart of Stanford Health Care, which runs 3 hospitalsPatients rate it 3 of 5 · 74% would definitely recommend it
    Overall rating: 5 of 5 starsBetter than the national rate — Central Line Associated Bloodstream Infection (ICU + select Wards): 0.178, Oct 2024 – Sep 2025Better than the national rate — Clostridium Difficile (C.Diff): 0.237, Oct 2024 – Sep 2025
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.

Every scored measure at Stanford Health Care
Perioperative pulmonary embolism or deep vein thrombosis rateComplications and deaths5.31 (4.24 to 6.37) · 8,661 casesWorseJul 2022 – Jun 2024
Rate of inpatient admissions for patients receiving outpatient chemotherapyUnplanned return visits14.1 (12.7 to 15.7) · 2,191 casesWorseJan 2024 – Dec 2024
Postoperative respiratory failure rateComplications and deaths4.08 (1.95 to 6.21) · 5,296 casesBetterJul 2022 – Jun 2024
Catheter Associated Urinary Tract Infections (ICU + select Wards)Infections0.317BetterOct 2024 – Sep 2025
Clostridium Difficile (C.Diff)Infections0.446BetterOct 2024 – Sep 2025
SSI - Colon SurgeryInfections0.241BetterOct 2024 – Sep 2025
Ratio of unplanned hospital visits after hospital outpatient surgeryUnplanned return visits0.7 (0.6 to 0.9) · 3,348 casesBetterJan 2024 – Dec 2024
Abdominopelvic accidental puncture or laceration rateComplications and deaths1.06 (0.45 to 1.67) · 5,374 casesNo differentJul 2022 – Jun 2024
CMS Medicare PSI 90: Patient safety and adverse events compositeComplications and deaths0.86 (0.72 to 1)No differentJul 2022 – Jun 2024
Death rate among surgical inpatients with serious treatable complicationsComplications and deaths166.09 (137.88 to 194.3) · 470 casesNo differentJul 2022 – Jun 2024
Death rate for CABG surgery patientsComplications and deaths1.1 · 192 casesNoneJul 2022 – Jun 2025
Death rate for COPD patientsComplications and deaths6.4 · 146 casesNoneJul 2022 – Jun 2025
Death rate for heart attack patientsComplications and deaths9.7 · 253 casesNoneJul 2022 – Jun 2025
Death rate for heart failure patientsComplications and deaths6.3 · 880 casesNoneJul 2022 – Jun 2025
Death rate for pneumonia patientsComplications and deaths10.3 · 935 casesNoneJul 2022 – Jun 2025
Death rate for stroke patientsComplications and deaths8.7 · 501 casesNoneJul 2023 – Jun 2025
Hybrid Hospital-Wide All-Cause Risk Standardized Mortality RateComplications and deaths2.1 · 7,730 casesNoneJul 2024 – Jun 2025
Iatrogenic pneumothorax rateComplications and deaths0.13 (0 to 0.27) · 20,799 casesNo differentJul 2022 – Jun 2024
In-hospital fall-associated fracture rateComplications and deaths0.28 (0.14 to 0.43) · 23,182 casesNo differentJul 2022 – Jun 2024
Postoperative acute kidney injury requiring dialysis rateComplications and deaths0.94 (0.2 to 1.68) · 5,694 casesNo differentJul 2022 – Jun 2024
Postoperative hemorrhage or hematoma rateComplications and deaths2.36 (1.54 to 3.19) · 7,846 casesNo differentJul 2022 – Jun 2024
Postoperative sepsis rateComplications and deaths5.2 (3.76 to 6.64) · 5,603 casesNo differentJul 2022 – Jun 2024
Postoperative wound dehiscence rateComplications and deaths1.38 (0.23 to 2.53) · 2,211 casesNo differentJul 2022 – Jun 2024
Pressure ulcer rateComplications and deaths0.52 (0.21 to 0.83) · 19,915 casesNo differentJul 2022 – Jun 2024
Rate of complications for hip/knee replacement patientsComplications and deaths3.6 · 416 casesNoneApr 2023 – Mar 2025
Central Line Associated Bloodstream Infection (ICU + select Wards)Infections0.869No differentOct 2024 – Sep 2025
MRSA BacteremiaInfections0.857No differentOct 2024 – Sep 2025
SSI - Abdominal HysterectomyInfections0.368No differentOct 2024 – Sep 2025
Acute Myocardial Infarction (AMI) 30-Day Readmission RateUnplanned return visits16.2 · 247 casesNoneJul 2023 – Jun 2025
Heart failure (HF) 30-Day Readmission RateUnplanned return visits20.5 · 1,021 casesNoneJul 2023 – Jun 2025
Hospital return days for heart attack patientsUnplanned return visits47.8 · 258 casesNoneJul 2022 – Jun 2025
Hospital return days for heart failure patientsUnplanned return visits-1.6 · 990 casesNoneJul 2022 – Jun 2025
Hospital return days for pneumonia patientsUnplanned return visits20.8 · 976 casesNoneJul 2022 – Jun 2025
Pneumonia (PN) 30-Day Readmission RateUnplanned return visits16.5 · 959 casesNoneJul 2023 – Jun 2025
Rate of emergency department (ED) visits for patients receiving outpatient chemotherapyUnplanned return visits5.2 (4.4 to 6.2) · 2,191 casesNo differentJan 2024 – Dec 2024
Rate of readmission after hip/knee replacementUnplanned return visits5.1 · 425 casesNoneJul 2023 – Jun 2025
Rate of readmission for CABGUnplanned return visits9.6 · 158 casesNoneJul 2023 – Jun 2025
Rate of readmission for chronic obstructive pulmonary disease (COPD) patientsUnplanned return visits19.6 · 183 casesNoneJul 2023 – Jun 2025
Rate of unplanned hospital visits after colonoscopy (per 1,000 colonoscopies)Unplanned return visits12.7 (10.4 to 15.4) · 4,578 casesNo differentJan 2022 – Dec 2024

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

Patient survey stars by topic at Stanford Health Care
Cleanliness4
Nurse communication4
Doctor communication4
Communication about medicines3
Discharge information4
Overall hospital rating4
Quietness2
Recommend hospital5
Share of patients giving the best answer at Stanford Health Care
Room was "always" clean75%
Nurses "always" communicated well82%
Doctors "always" communicated well81%
Staff "always" explained63%
Yes, staff "did" give patients this information89%
Yes, staff "did" give patients information about help after discharge89%
Doctors "always" explained things so they could understand76%
Doctors "always" listened carefully80%
Doctors "always" treated them with courtesy and respect87%
Patients who gave a rating of "9" or "10" (high)79%
Staff "always" explained new medications76%
Nurses "always" explained things so they could understand77%
Nurses "always" listened carefully79%
Nurses "always" treated them with courtesy and respect88%
"Always" quiet at night53%
"YES", patients would definitely recommend the hospital83%
Staff "always" explained possible side effects50%
Yes, staff "did" give patients information about possible symptoms90%
See every measure and the patient survey for Stanford Health Care Tri-Valley

Behind the star rating — Deaths: 2 better, 6 the same, 0 worse of 8 measures. Safety: 2 better, 5 the same, 0 worse of 7 measures. Readmissions: 2 better, 7 the same, 0 worse of 9 measures. The star rating is worked out from an earlier period than the measures below, so the two can disagree.

Every scored measure at Stanford Health Care Tri-Valley
Central Line Associated Bloodstream Infection (ICU + select Wards)Infections0.178BetterOct 2024 – Sep 2025
Clostridium Difficile (C.Diff)Infections0.237BetterOct 2024 – Sep 2025
Abdominopelvic accidental puncture or laceration rateComplications and deaths0.79 (0 to 1.73) · 1,041 casesNo differentJul 2022 – Jun 2024
CMS Medicare PSI 90: Patient safety and adverse events compositeComplications and deaths0.79 (0.5 to 1.08)No differentJul 2022 – Jun 2024
Death rate among surgical inpatients with serious treatable complicationsComplications and deaths145.81 (96.5 to 195.12) · 72 casesNo differentJul 2022 – Jun 2024
Death rate for CABG surgery patientsComplications and deaths2.9 · 55 casesNoneJul 2022 – Jun 2025
Death rate for COPD patientsComplications and deaths8.6 · 92 casesNoneJul 2022 – Jun 2025
Death rate for heart attack patientsComplications and deaths12.5 · 96 casesNoneJul 2022 – Jun 2025
Death rate for heart failure patientsComplications and deaths9.5 · 395 casesNoneJul 2022 – Jun 2025
Death rate for pneumonia patientsComplications and deaths10.3 · 391 casesNoneJul 2022 – Jun 2025
Death rate for stroke patientsComplications and deaths10.1 · 162 casesNoneJul 2023 – Jun 2025
Hybrid Hospital-Wide All-Cause Risk Standardized Mortality RateComplications and deaths3 · 1,736 casesNoneJul 2024 – Jun 2025
Iatrogenic pneumothorax rateComplications and deaths0.16 (0 to 0.37) · 4,425 casesNo differentJul 2022 – Jun 2024
In-hospital fall-associated fracture rateComplications and deaths0.22 (0.02 to 0.41) · 4,771 casesNo differentJul 2022 – Jun 2024
Perioperative pulmonary embolism or deep vein thrombosis rateComplications and deaths3.45 (1.46 to 5.44) · 1,403 casesNo differentJul 2022 – Jun 2024
Postoperative acute kidney injury requiring dialysis rateComplications and deaths1.5 (0.05 to 2.94) · 645 casesNo differentJul 2022 – Jun 2024
Postoperative hemorrhage or hematoma rateComplications and deaths1.81 (0.38 to 3.24) · 1,279 casesNo differentJul 2022 – Jun 2024
Postoperative respiratory failure rateComplications and deaths8.53 (3.2 to 13.85) · 639 casesNo differentJul 2022 – Jun 2024
Postoperative sepsis rateComplications and deaths5.15 (1.89 to 8.41) · 648 casesNo differentJul 2022 – Jun 2024
Postoperative wound dehiscence rateComplications and deaths1.61 (0.14 to 3.07) · 370 casesNo differentJul 2022 – Jun 2024
Pressure ulcer rateComplications and deaths0.16 (0 to 0.83) · 4,160 casesNo differentJul 2022 – Jun 2024
Rate of complications for hip/knee replacement patientsComplications and deaths4 · 74 casesNoneApr 2023 – Mar 2025
Catheter Associated Urinary Tract Infections (ICU + select Wards)Infections0.369No differentOct 2024 – Sep 2025
MRSA BacteremiaInfections1.112No differentOct 2024 – Sep 2025
SSI - Colon SurgeryInfections0No differentOct 2024 – Sep 2025
Acute Myocardial Infarction (AMI) 30-Day Readmission RateUnplanned return visits13.1 · 110 casesNoneJul 2023 – Jun 2025
Heart failure (HF) 30-Day Readmission RateUnplanned return visits20.1 · 437 casesNoneJul 2023 – Jun 2025
Hospital return days for heart attack patientsUnplanned return visits-5.8 · 94 casesNoneJul 2022 – Jun 2025
Hospital return days for heart failure patientsUnplanned return visits-19.3 · 456 casesNoneJul 2022 – Jun 2025
Hospital return days for pneumonia patientsUnplanned return visits-0.3 · 402 casesNoneJul 2022 – Jun 2025
Pneumonia (PN) 30-Day Readmission RateUnplanned return visits15.8 · 358 casesNoneJul 2023 – Jun 2025
Rate of emergency department (ED) visits for patients receiving outpatient chemotherapyUnplanned return visits6.8 (4.7 to 9.6) · 198 casesNo differentJan 2024 – Dec 2024
Rate of inpatient admissions for patients receiving outpatient chemotherapyUnplanned return visits10.1 (7.5 to 13.6) · 198 casesNo differentJan 2024 – Dec 2024
Rate of readmission after hip/knee replacementUnplanned return visits5.3 · 80 casesNoneJul 2023 – Jun 2025
Rate of readmission for CABGUnplanned return visits10.9 · 46 casesNoneJul 2023 – Jun 2025
Rate of readmission for chronic obstructive pulmonary disease (COPD) patientsUnplanned return visits19.3 · 92 casesNoneJul 2023 – Jun 2025
Rate of unplanned hospital visits after colonoscopy (per 1,000 colonoscopies)Unplanned return visits12.4 (9.6 to 16.2) · 1,532 casesNo differentJan 2022 – Dec 2024
Ratio of unplanned hospital visits after hospital outpatient surgeryUnplanned return visits1 (0.8 to 1.2) · 929 casesNo differentJan 2024 – Dec 2024

What patients said (1,268 patients answered, 26% of those asked)

Patient survey stars by topic at Stanford Health Care Tri-Valley
Cleanliness3
Nurse communication3
Doctor communication4
Communication about medicines3
Discharge information4
Overall hospital rating3
Quietness2
Recommend hospital4
Share of patients giving the best answer at Stanford Health Care Tri-Valley
Room was "always" clean65%
Nurses "always" communicated well77%
Doctors "always" communicated well79%
Staff "always" explained58%
Yes, staff "did" give patients this information88%
Yes, staff "did" give patients information about help after discharge88%
Doctors "always" explained things so they could understand74%
Doctors "always" listened carefully78%
Doctors "always" treated them with courtesy and respect86%
Patients who gave a rating of "9" or "10" (high)70%
Staff "always" explained new medications72%
Nurses "always" explained things so they could understand73%
Nurses "always" listened carefully74%
Nurses "always" treated them with courtesy and respect84%
"Always" quiet at night42%
"YES", patients would definitely recommend the hospital74%
Staff "always" explained possible side effects44%
Yes, staff "did" give patients information about possible symptoms89%

Original Medicare doctor bills

$106,589

Medicare paid this office $106,589 for 674 people.

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

Largest Original Medicare bills
Special stained specimen slides to examine tissue, each additional procedure176$15,865$25
Evaluation of fine needle aspirate with interpretation and report164$14,257$63
Pathology examination of tissue using a microscope, moderately high complexity48$13,558$74
Pathology examination of tissue using a microscope, intermediate complexity295$12,571$32
Microscopic genetic analysis of tumor, manual115$9,750$36
See all 17 services
Every Original Medicare service billed
Special stained specimen slides to examine tissue, each additional procedure176$15,865$25
Evaluation of fine needle aspirate with interpretation and report164$14,257$63
Pathology examination of tissue using a microscope, moderately high complexity48$13,558$74
Pathology examination of tissue using a microscope, intermediate complexity295$12,571$32
Microscopic genetic analysis of tumor, manual115$9,750$36
Special stained specimen slides to examine tissue, initial procedure199$7,273$31
Surgical pathology consultation and report on referred slides prepared elsewhere92$6,818$73
Microscopic genetic analysis of tissue, manual, each additional multiplex stain procedure67$6,560$57
Cell examination of specimen, selective cellular enhancement technique191$5,029$25
Evaluation of fine needle aspirate112$3,999$31
Fine needle aspiration biopsy using ultrasound guidance, first growth34$2,164$64
Pathology examination of specimen during surgery, first tissue block12$1,945$56
Pap test, evaluation of fine needle aspirate, immediate, each additional evaluation episode42$1,394$20
Genetic sequencing localization, initial procedure21$845$38
Special stained specimen slides to identify organisms including interpretation and report12$833$24
Surgical pathology consultation and report on referred material requiring preparation of slides11$798$73
Screening cytopathology, cervical or vaginal (any reporting system), collected in preservative fluid, automated thin layer preparation, requiring interpretation by physician11$366$31

Who their Medicare patients are

674 Original Medicare patients in 2024. Average age 74 · Under 65 6% · 85 and older 11% · Women 64% · Also on Medicaid 23% · Health risk score 1.58. Above the middle of the specialty; the typical pathology clinician is at 1.55.

Conditions among them: High blood pressure 68% · Cancer 51% · Diabetes 28% · Coronary heart disease 25% · Chronic kidney disease 23% · Atrial fibrillation 20% · Heart failure 17% · Depression 17% · COPD 15% · Stroke 9% · Dementia 7%.

The office billed $1,518,713, Medicare allowed $135,237 and paid $106,589; for 2,805 services of 32 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

Original Medicare by year
20246742,805741.58$1,518,713$106,589
20236682,476741.57$1,150,659$99,276
2022202669741.54$262,349$24,741

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: 20 services

Original Medicare services billed in 2023
Pathology examination of tissue using a microscope, moderately high complexity70$17,932$75
Microscopic genetic analysis of tumor, manual140$14,865$38
Special stained specimen slides to examine tissue, each additional procedure136$11,439$26
Pathology examination of tissue using a microscope, intermediate complexity266$11,234$34
Evaluation of fine needle aspirate with interpretation and report121$10,793$63
Special stained specimen slides to examine tissue, initial procedure175$6,341$31
Surgical pathology consultation and report on referred slides prepared elsewhere74$5,711$75
Cell examination of specimen, selective cellular enhancement technique188$4,955$25
Microscopic genetic analysis of tissue, manual, each additional multiplex stain procedure52$3,499$56
Evaluation of fine needle aspirate76$2,715$32
Fine needle aspiration biopsy using ultrasound guidance, first growth27$1,713$63
Pathology examination of specimen during surgery, first tissue block18$1,711$57
Surgical pathology consultation and report on referred material requiring preparation of slides12$942$79
Pathology cytologic examination of specimen during surgery, initial site13$797$57
Special stained specimen slides to identify organisms including interpretation and report11$746$24
Pap test, evaluation of fine needle aspirate, immediate, each additional evaluation episode19$654$20
Genetic sequencing localization, initial procedure15$587$39
Special stained specimen slides to examine tissue, each multiplex procedure13$453$35
Cell examination of specimen, concentration technique14$286$20
Pathology examination of tissue using a microscope, moderately low complexity14$226$10

2022: 9 services

Original Medicare services billed in 2022
Evaluation of fine needle aspirate with interpretation and report52$4,435$64
Special stained specimen slides to examine tissue, each additional procedure38$3,813$26
Pathology examination of tissue using a microscope, intermediate complexity89$3,509$34
Cell examination of specimen, selective cellular enhancement technique104$2,714$25
Microscopic genetic analysis of tumor, manual22$1,488$38
Special stained specimen slides to examine tissue, initial procedure43$1,462$32
Surgical pathology consultation and report on referred slides prepared elsewhere19$1,446$76
Evaluation of fine needle aspirate39$1,435$33
Pap test, evaluation of fine needle aspirate, immediate, each additional evaluation episode13$382$20

Medicaid work

$8,985 in 2024

Medicaid paid $8,985 for 302 billed services this clinician did in 2024, up to 24 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.

Largest Medicaid services in 2024
TISSUE EXAM BY PATHOLOGIST115$3,441
Cytopathology, selective cellular enhancement technique with interpretation (eg, liquid based slide preparation method), except cervical or vaginal46$1,384
IMHCHEM/IMCYTCHM EA ADD ANTB51$1,240
CYTP EVAL FINE NEEDLE ASPIRATE INTERP & REPORT30$1,011
Immunohistochemistry or immunocytochemistry, per specimen; initial single antibody stain procedure38$998
Morphometric analysis, tumor immunohistochemistry (eg, Her-2/neu, estrogen receptor/progesterone receptor), quantitative or semiquantitative, per specimen, each single antibody stain procedure; manual22$911
Medicaid work by year
2024302624$8,985
2023175520$6,683
202212112$443
See the largest Medicaid services in earlier years

2023

Largest Medicaid services in 2023
TISSUE EXAM BY PATHOLOGIST97$3,368
Morphometric analysis, tumor immunohistochemistry (eg, Her-2/neu, estrogen receptor/progesterone receptor), quantitative or semiquantitative, per specimen, each single antibody stain procedure; manual17$1,368
Cytopathology, selective cellular enhancement technique with interpretation (eg, liquid based slide preparation method), except cervical or vaginal33$853
Immunohistochemistry or immunocytochemistry, per specimen; initial single antibody stain procedure15$628
CYTP EVAL FINE NEEDLE ASPIRATE INTERP & REPORT13$466

2022

Largest Medicaid services in 2022
Cytopathology, selective cellular enhancement technique with interpretation (eg, liquid based slide preparation method), except cervical or vaginal12$443

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
1043674195
Licence
CA A151114California A151114: Current · expires 2027-07-31
Gender
Female
More record details
Sole proprietor
Yes
Taxonomy
Federal specialty code 207ZP0102X (207ZP0102X); Federal specialty code 207ZC0500X (207ZC0500X)
Mailing address
300 Pasteur Dr, Stanford, CA, 94305
NPI first listed
2016-04-05
NPI last updated
2024-03-13
NPI record certified
2024-03-13

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