Lukejohn Day


Dr. Day is a professor of medicine at UCSF and the Chief Medical Officer at the Zuckerberg San Francisco General Hospital (ZSFG). His research interests center on organizational design, quality and systems improvement, and development of efficiency models for healthcare system delivery to vulnerable patient populations. Specifically, his research explores the delivery of healthcare through the endoscopy center. He is currently working on developing key innovations that can be implemented at the ZSFG endoscopy center that focus on maximizing staff and physician efficiency, improving patient access to endoscopic care, and strengthening patient and staff satisfaction. His research has spanned projects that have examined the quality of outpatient GI consultation notes, improving patient access though implementing a set of discharge criteria after endoscopy, studying the informed consent process in endoscopy education classes and improving endoscopy center operational efficiency using time and motion studies and simulation modeling.
Fellowship, 2010 - Gastroenterology, University of California, San Francisco
Residency, 2007 - Internal Medicine, University of California, San Francisco
M.D., 2004 - Medicine, Stanford University
B.S., 1998 - Chemistry, Yale University
  1. Shaukat A, Tuskey A, Rao VL, Dominitz JA, Murad MH, Keswani RN, Bazerbachi F, Day LW, (ASGE Quality Assurance in Endoscopy Committee Chair). Interventions to improve adenoma detection rates for colonoscopy. 2022. PMID: 35680469

  2. Bazerbachi F, Panganamamula K, Nieto JM, Murad MH, Keswani RN, Shaukat A, Day LW. Interventions to improve the performance of upper GI endoscopy quality indicators. 2022. PMID: 35680470

  3. ASGE QUALITY ASSURANCE IN ENDOSCOPY COMMITTEE, Taunk P, Shimpi R, Singh R, Collins J, Muthusamy VR, Day LW. GI endoscope reprocessing: a comparative review of organizational guidelines and guide for endoscopy units and regulatory agencies. 2022. PMID: 35303991

  4. Day LW, Savides TJ. Patient Experience in the Gastrointestinal Endoscopy Unit. 2021. PMID: 34864159

  5. Kwok K, Hasan N, Duloy A, Murad F, Nieto J, Day LW. American Society for Gastrointestinal Endoscopy radiation and fluoroscopy safety in GI endoscopy. 2021. PMID: 34399965

  6. Stern RJ, Rafferty HF, Robert AC, Taniguchi C, Gregory B, MD, Khoong EC, Handley MA, Day LW, and Chen E.. Concentrating Vaccines in Neighborhoods with High Covid-19 Burden 2021. PMID:

  7. Day LW, Muthusamy VR, Collins J, Kushnir VM, Sawhney MS, Thosani NC, Wani S. Multisociety guideline on reprocessing flexible GI endoscopes and accessories. 2021. PMID: 33353611

  8. Han S, Obuch JC, Keswani RN, Hall M, Patel SG, Menard-Katcher P, Simon V, Ezekwe E, Aagaard E, Ahmad A, Alghamdi S, Austin K, Brimhall B, Broy C, Carlin L, Cooley M, Di Palma JA, Duloy AM, Early DS, Ellert S, Gaumnitz EA, Goyal J, Kathpalia P, Day L, El-Nachef N, Kerman D, Lee RH, Lunsford T, Mittal M, Morigeau K, Pietrak S, Piper M, Shah AS, Shapiro AB, Shergill A, Sonnier W, Sorrell C, Vignesh S, Wani S. THE EFFECT OF INDIVIDUALIZED FEEDBACK ON LEARNING CURVES IN EGD AND COLONOSCOPY: A CLUSTER RANDOMIZED CONTROLLED TRIAL. 2019. PMID: 31715173

  9. Alsayid M, Singh MH, Issaka R, Laleau V, Day L, Lee J, Allison J, Somsouk M. Yield of Colonoscopy After a Positive Result From a Fecal Immunochemical Test OC-Light. 2018. PMID: 29660528

  10. Calderwood AH, Day LW, Muthusamy VR, Collins J, Hambrick RD, Brock AS, Guda NM, Buscaglia JM, Petersen BT, Buttar NS, Khanna LG, Kushnir VM, Repaka A, Villa NA, Eisen GM. ASGE guideline for infection control during GI endoscopy. 2018. PMID: 29573782

  11. Issaka RB, Singh MH, Rachocki C, Day LW, Horton C, Somsouk M. Missed Opportunities in Colorectal Cancer Prevention in Patients With Inadequate Bowel Preparations. 2018. PMID: 29330098

  12. Baumgardner JM, Sewell JL, Day LW. Assessment of quality indicators among nurse practitioners performing upper endoscopy. 2017. PMID: 28879227

  13. Day LW, Cohen J, Greenwald D, Petersen BT, Schlossberg NS, Vicari JJ, Calderwood AH, Chapman FJ, Cohen LB, Eisen G, Gerstenberger PD, Hambrick RD, Inadomi JM, MacIntosh D, Sewell JL, Valori R. Quality indicators for gastrointestinal endoscopy units. 2017. PMID: 29905282

  14. Kouanda AM, Somsouk M, Sewell JL, Day LW. Urgent colonoscopy in patients with lower GI bleeding: a systematic review and meta-analysis. Volume 86 of Issue 1. 2017. PMID: 28174123

  15. Lee A, Aditi A, Bhat YM, Binmoeller KF, Hamerski C, Sendino O, Kane S, Cello JP, Day LW, Mohamadnejad M, Muthusamy VR, Watson R, Klapman JB, Komanduri S, Wani S, Shah JN. Endoscopic ultrasound-guided biliary access versus precut papillotomy in patients with failed biliary cannulation: a retrospective study. Volume 49 of Issue 2. 2017. PMID: 28107764

  16. Issaka RB, Singh MH, Oshima SM, Laleau VJ, Rachocki CD, Chen EH, Day LW, Sarkar U, Somsouk M. Inadequate Utilization of Diagnostic Colonoscopy Following Abnormal FIT Results in an Integrated Safety-Net System. Volume 112 of Issue 2. 2016. PMID: 28154400

  17. Hassid BG, Day LW, Awad MA, Sewell JL, Osterberg EC, Breyer BN. Using Search Engine Query Data to Explore the Epidemiology of Common Gastrointestinal Symptoms. 2016. PMID: 27878646

  18. Kidambi TD, Lee R, Terdiman JP, Day L. Successful implementation of Lynch syndrome screening in a safety net institution. 2016. PMID: 27372833

  19. Day LW, Gonzalez S, Ladd AM, Bucobo JC, Pickett-Blakely O, Tilara A, Christie J. Diversity in gastroenterology in the United States: Where are we now? Where should we go? 2016. PMID: 26810008

  20. Day LW, Nazareth M, Sewell JL, Williams JL, Lieberman DA. Practice variation in PEG tube placement: trends and predictors among providers in the United States. 2015. PMID: 25845635

  21. Day LW. Nonphysician Performance of Endoscopy. 2015. PMID: 27099590

  22. Sewell JL, Telischak KS, Day LW, Kirschner N, Weissman A. Preconsultation exchange in the United States: use, awareness, and attitudes. 2014. PMID: 25741872

  23. Sewell JL, Telischak KS, Day LW, Kirschner N, Weissman A. Preconsultation exchange in the United States: use, awareness, and attitudes. 2014. PMID: 25665191

  24. Tuot DS, Sewell JL, Day L, Leeds K, Chen AH. Increasing access to specialty care: patient discharges from a gastroenterology clinic. 2014. PMID: 25365684

  25. Day LW, Velayos F. Colorectal cancer of the elderly. 2014. PMID: 24938590

  26. Gupta S, Sussman DA, Doubeni CA, Anderson DS, Day L, Deshpande AR, Elmunzer BJ, Laiyemo AO, Mendez J, Somsouk M, Allison J, Bhuket T, Geng Z, Green BB, Itzkowitz SH, Martinez ME. Challenges and possible solutions to colorectal cancer screening for the underserved. Volume 106 of Issue 4. 2014. PMID: 24681602

  27. Day LW, Siao D, Inadomi JM, Somsouk M. Non-physician performance of lower and upper endoscopy: a systematic review and meta-analysis. Volume 46 of Issue 5. 2014. PMID: 24627086

  28. Day LW, Lin L, Somsouk M. Adverse events in older patients undergoing ERCP: a systematic review and meta-analysis. Volume 2 of Issue 1. 2014. PMID: 26134610

  29. Day LW, Velayos F. Colorectal cancer and the elderly. 2014. PMID: 24267607

  30. Calderwood AH, Chapman FJ, Cohen J, Cohen LB, Collins J, Day LW, Early DS. Guidelines for safety in the gastrointestinal endoscopy unit. 2014. PMID: 24485393

  31. Sewell JL, Somsouk M, Shah SC, Day LW. Commentary: Towards an effective and safe treatment of small intestine bacterial overgrowth - Authors' reply. Volume 38 of Issue 11-12. 2013. PMID: 24206377

  32. Day LW, Bhuket T, Allison J. FIT testing: an overview. Volume 15 of Issue 11. 2013. PMID: 24218070

  33. Shah SC, Day LW, Somsouk M, Sewell JL. Meta-analysis: antibiotic therapy for small intestinal bacterial overgrowth. Volume 38 of Issue 8. 2013. PMID: 24004101

  34. Sewell JL, Day LW, Tuot DS, Alvarez R, Yu A, Chen AH. A brief, low-cost intervention improves the quality of ambulatory gastroenterology consultation notes. 2013. PMID: 23791206

  35. Day LW, Michelle N, Sewell JL. Open Journal of Gastroenterology 2013. PMID:

  36. Siao D, Thoeni R, Grenert JP, Day LW. A rare presentation of abdominal pain: idiopathic mesenteric phlebosclerosis. 2012. PMID: 23160302

  37. Day LW, Kwon A, Inadomi JM, Walter LC, Somsouk M. Adverse events in older patients undergoing colonoscopy: a systematic review and meta-analysis. Volume 74 of Issue 4. 2011. PMID: 21951478

  38. Day LW, Cello JP, Somsouk M, Inadomi JM. Prevalence of gastric cancer versus colorectal cancer in Asians with a positive fecal occult blood test. Volume 30 of Issue 5. 2011. PMID: 21948130

  39. Day LW, Walter LC, Velayos F. Colorectal cancer screening and surveillance in the elderly patient. 2011. PMID: 21519362